Notes on the work of the Medical Research Council Applied Psychology Unit 1944-1997

This overview is a compilation drawn from several sources with material drawn from previous published histories and unit progress reports. It was sent to all the delegates a to remind them of the full range of work carried out at the Unit.

Formation of the APU: 1944 to 1945

Early in 1944 the MRC formally established a ‘Unit for Research in Applied Psychology’ within the University department. It was directed by K. J. W. Craik, a man who combined strong interests both in advanced engineering and in the explanation of behaviour: its Honorary Director was Professor Frederic Bartlett, who welcomed and developed the application of experimental psychology to solve problems of man-machine relationships.

Reporting in Nature that first year, Craik (1944) pointed out that certain common principles were emerging from the Unit’s research, much of which had necessarily been of an ad hoc character. With typical foresight he was already anticipating the application of these principles to peacetime problems. Studies of prolonged watch-keeping (Mackworth 1950) were seen to be related to the determination of optimal work-periods in industry. Techniques developed to study fatigue and discomfort (Russell Davis 1948) were suggested as a possible method for assessing progress of patients recovering from physical and mental illness. Work on control problems was obviously applicable to the future design of machine tools and more complex man-machine systems. If there was a shift in emphasis from earlier days, it was in the prominence Craik gave to the idea of fitting the job to the man, rather than vice versa. As he put it, “This approach . . . puts the industrial jobs necessary for improved standards of living within the power of the majority, whereas psychological selection alone, especially where the job has been made unnecessarily difficult, may result in a high rate of rejection and unemployment.” Intelligence testing was continued, however, to meet the need for allocation of workers to tasks which were unavoidably difficult. It is interesting to note from Craik’s report that, of the eleven research staff employed in early 1944, six were graduates in psychology, four in medicine and one in physiology. This selection of Unit staff from a variety of disciplines became wider ranging in later years, when psychologists with additional qualifications in physics and engineering were employed to deal with increasingly complex problems of control systems.

Tragically, Craik never lived to see his predictions fulfilled. He died in 1945, the victim of a road accident on the day war ended.

It is important to understand that the Unit’s work was really a direct extension of work carried out for the MRC in the Psychological Laboratory across the war time years. Indeed in what appears to be something very like a progress report presented a year after Craik’s death there were listed 18 Unit staff (Including Bartlett and Farmer, who were University appointments). They were working on seven “topics” described as follows in the 1946 report:

1. Selection and training of personnel in the Services and in Industry. In selection the main attention has been given to operations involving a rather high degree of intelligence. In training particular regard has been paid to the principles of design of synethetic training instruments and their effective use.

2. The design of display and controls in instruments requiring precision work in war and industry. The increase of mechanisation in all directions has developed many new problems of how to design displays and controls of precision apparatus so that the normal operative may have the best opportunity to achieve efficiency without strain. Much attention has been, and still is being given, to these problems, with widespread practical results.

3. The experimental study of special working conditions, particularly ofsleeplessness, prolonged hours of continuous operation, high speed pressure, tropical heat, extreme of noise, and a variety of harassing agents. This has involved much study of the effects of drugs of the benzedine group and the opening of a new chapter in the study of fatigue and allied states by the development of methods for measuring the efficiency of skills both of low and of high grade.

4. A large variety of special sensory problems. Contributions of theoretical and practical importance have been made to visual problems of scanning and plotting; of dark adaptation, of the tracking of targets and of special conditions of low and high illumination.

5. The study of accidents and of means for their prevention. Transport accidents have been given considerable attention, although the results of their study have not so far, for a variety of reasons, been given much practical application. More recently considerable progress has been made in the investigation of industrial accidents, particularly certain classes of accident common in mining operations.

6. Studies in perceptual efficiency and practical capacity. These are still in the early research stages. It seems certain that perceptual efficiency is both a matter of great practical importance and is not adequately measured or assessed by any existing tests of intelligence. Some progress has been made toward establishing methods for its adequate prognosis. A beginning of some promise has also been made in an attempt to determine experimentally the basic mental functions of various forms of manipulatory skill and practical capacity.

7. Attempts to develop non-paper methods for the determination of traits of temperaments and personality.

Early Outputs and Achievements:

The principal outputs at the time were published papers, APU reports, and a range of reports to committees concerned with army, naval and air force personnel. The 1946 overview and APU papers from the time give a sample of the work done. It is also evident from the publications of the time that much of the work was responsive –research conducted to answer questions originating from various military, government or medical organisations. Much of the detail of the defence work is no longer preserved (or at least accessible by us). While some reports have titles that allow us to make pretty good inferences about the work described, others only hint at it (e.g .some personal notes made in the last few years of his life by Mackworth made it clear that “Harassing agents” referred to in 3 above were tear gas and arsenical smoke whose effects on potential invaders he compared using a peg board task and a continuous tracking task). Some work that was published later (e.g. a report by Bartlett and Mackworth on Planned Seeing, HMSO, 1950 documents research done on control rooms for Fighter Command and the synthetic training of pathfinder air bombers in visual centring of target indicators) provides a very clear picture of how innovative research methods were developed to provide output for practical application.

The Post-war Years: 1945-1958

Following the death of Craik, the work of the APU continued under the general direction of Sir Frederic Bartlett, with Dr Mackworth as Assistant Director. Greater emphasis was placed on studies of prolonged visual search. It was recognized (Mackworth 1956) that advancing technology had changed the whole character of the human skills required in industry and the Services. More and more, “man” was becoming a monitor of complex equipment. The need for research on manual skills was dying and greater attention was being given to perceptual and decision-taking skills. Information relevant to the design of man-machine interfaces was all-important, together with the need to define the limits of human behaviour under stress.

During these early post-war years, research on individual differences continued,although the emphasis shifted to problems of vocational guidance, intelligence and personality testing, and the selection of university students. Individual differences, and the concept of ‘accident proneness’, were also of central importance to the continuing studies of accident prevention, both in industry and on the road. However, a number of people were beginning to establish general principles of human behaviour from research using healthy adult subjects. Dr Mackworth continued his studies of perception and decision-taking, with an additional interest in environmental heat and cold. Dr E. C. Poulton developed the concept of ‘perceptual anticipation’, especially in relation to tracking skill, and Mr D. E. Broadbent began his series of experiments on effects of environmental noise. Mr R. Conrad and Mr C. B. Gibbs, working on industrial productivity, were concentrating on the question of timing in skilled movements. The posthumously published papers of Dr Craik (1947 and 1948) and the work of Dr Hick (1947, 1951, 1952) were already laying the foundations for the important step forward taken by the application of information theory to psychology. Work on environmental heat was being undertaken by Dr A. Carpenter and Mr R. D. Pepler, partly at the Tropical Research Unit which the MRC maintained jointly with the Royal Navy in Singapore. Most of the practical problems were still coming from the Services, usually the Royal Navy or Royal Air Force, but the number of civilian and industrial problems was increasing.

In 1949 pressure for accommodation forced the Unit to expand outside the University and an annexe was established in a large house in the city. The problem of adequate testing facilities was acute, however, and in 1953 the entire Unit moved to its present position in a large house on the outskirts of the city. Whereas the Unit had its origins firmly embedded in the Psychological Laboratory of the University, the appointment of Prof Zangwill in the University and Dr Mackworth as the director of the APU led to what amounted at the time to a functional “divorce” between the APU and the Laboratory. Sir Frederic Bartlett nonetheless continued to act as a consultant to the Unit along with Professor G. C. Drew.

As far as coverage is concerned, the opening overview page of the unit report for 1950-53 shows how the objectives, themes and future trends were seen at the time:

1. GENERAL OBJECTIVES

The aims of this Unit are to observe and measure human behaviour in order to establish general principles about healthy human performance. It is believed that such principles should be of general scientific interest, and also of practical value when applied to men working either in Industry or the Services. The investigations usually consist of experimental studies of individual human activity. Most projects are aimed at devising measures of human achievement which will allow people to work more effectively with less fatigue and fewer accidents.

2. MAIN LINES

The researches can conveniently be grouped under eight main headings.

I. Unusual environments

II. Vigilance tasks and skill consistency

III. Information presentation

IV. Information measurement

V. Training

VI. Motor performance

VII. Sickness and accident studies

VIII. New devices and procedures

3. FUTURE TRENDS

In the future work will continue along all these lines with special attention to:-

(a) Studies of vigilance tasks and skill consistency

(b) Researches on information presentation

© New experiments on information measurement

(d) The experimental analysis of training

On the practical side, most of the problems come from the Services, usually from the Royal Navy or the Royal Air Force. More work is however, being done on civilian and industrial problems. There is also an increasing tendency for questions to appear with a medical background.

Throughout this period a number of important theories of human behaviour were beginning to emerge from the work of the Unit. For example, experiments and arguments in the 1950-53 report are clearly seeds of the synthesis presented by Broadbent (1958) in his seminal book Perception and Communication. This, of course, provided the stimulus for a great deal of research in applied and experimental psychology during subsequent years. Equally other influential thinkers were cutting their teeth on both practical and novel theoretical issues. Richard Gregory for example, worked both on how CO2 concentrations might affect performance in escapes from submarines as well as on information measurement. The following extract from the 1950-53 report illustrates that theoretical speculation was promoted rather than discouraged (Hick of course is the Hick of the Hick-Hyman law, while Miss Cane was the Statistical specialist on the group).

Gregory has devised a speculative account of brain function in terms of probability and induction and in this he had the help of Miss Cane. This work is related to Hick’s comment that the objective frequencies with which events occur do not exactly correspond to the subjective or psychologically effective probabilities. Gregory has started experiments in which various events occur with different objective frequencies during a series of presentations. The subject has to guess the next event. It will be possible to determine how different these frequencies must be before people begin to select one of the alternatives more frequently than any of the other possible choices. Gregory’ interesting paper is in fact a plea for more experiments on human learning in which the subjects have to form hypotheses and make definite predictions from a growing series of data. He has made the further suggestion that eye movement recordings could identify the sources of visual data that are providing crucial information in deciding between rival hypotheses. Another particularly stimulating idea is the proposal that studies should be made of inductive thinking to discover more about the ways in which people could decide when they have enough data to support a definite conclusion.

The interaction between practical problems of one sort or another and the development of theory has always been brought into focus when discussing the nature and influence of the work of the APU. The first diagram we know of on this point, thought to have been dreamed up by Mackworth, was included in the 1955 annual report entitled “Industrial Experiments in Progress.”

The Broadbent Directorship 1958 to 1974

In 1958 Dr Mackworth gave up his directorship and returned to full-time research with the Canadian Defence Research Medical Laboratories in Toronto. His place was taken by Mr Broadbent, with Dr Conrad and Dr Poulton jointly in the position of Assistant Director. The next available progress report for the Unit covers the years 1954-1960 and was prepared by Broadbent. At the time of that report there are 15 staff in addition to the Director and the two assistant directors. However, the Unit is clearly doing a great deal more in the way of international networking – with visiting scientists from Belgium, Holland, Canada, South Africa and, of course, the US where visiting workers came from Universities as well as US national, US Naval and US Air Force laboratories. Broadbent summarises the plan and output to 1960 in the following way:

The summary of research is built on the following plan. A man doing a job can be regarded from four aspects. First, there are the background conditions of work: heat, noise, etc. Second, there are the stimuli striking his senses: to which and to how many of these does he respond? Third, there are the internal operations performed on this information: the storage of items in memory, or the choice of particular actions. Fourth, there is the execution of actions once they have been chosen. Some research has been done in each of these areas, and although the division is somewhat arbitrary it has been used for want of a better.”

The entire Progress Report for this six year period included just 8 pages of description of past research, and future plans were covered in a couple of sentences at the end of each area covered. There were ten pages of references to published output. Throughout the period of Broadbent’s directorship, Unit research was reported on every three years with a visit being made by a committee every six years. The actual Progress Reports for these periods were not held on file here (though we have now recovered them from the Public Records Office). To remind us of the main themes, the following material has been extracted from a review of the Unit’s work published in 1971 by Brown, Batts & McGougan in Applied Ergonomics:

Application of psychological theories. In the Annual Reports circulated during the early years of his directorship, Broadbent selected for attention a range of work on the relation between signal probability and response time. This topic was becoming important to revised concepts of information theory (Broadbent 1957), to research on choice reaction time and stimulus-response compatibility (Leonard 1959), and to the work on industrial inspection tasks which were being initiated by Dr W. P. Colquhoun. Dr R. T. Wilkinson’s research on sleep-loss was of interest to the developing theories of the way in which a man’s general level of alertness varied from time to time and interacted with the level of stimulation produced by the task he was performing. Earlier research, which showed that the brain samples sensory information in chunks rather than taking it in continuously, was being related to practical tasks such as the perception of speech. The application of psychological theories to practical problems was apparent in a variety of publications at this time, for example: in Poulton’s (1959, 1960) research on the relation between perception of written material and the style of printing used; in Conrad’s (1960) research on immediate memory and its application to communications problems such as remembering long telephone numbers; and in Dale’s (1959) studies of searching strategies and fault-finding in electronic equipment. In addition, there were a number of methodological developments including Poulton’s work on asymmetric transfer effects in balanced experimental designs (Poulton & Freeman, 1966).

Individual differences. During the early 1960s there was renewed interest in individual differences, as determined by temperament and person-ality. Colquhoun (1960) was beginning to discover differential changes in vigilance performance among extroverts and introverts, depending upon the time of day at which the task was undertaken. Together with Corcoran (1964) he developed this interest in relation to the physiologically based concept of arousal which was gaining acceptance among psychologists, and Wilkinson (1961) demonstrated the importance of this concept for tasks performed after loss of sleep. Brown and Poulton (1961) were also interested in individual differences, but were concerned with methods for measuring the ability to process information, mainly as a means of assessing performance on tasks which were otherwise difficult to evaluate (Brown 1964). Information theory reconsidered. More theoretical concepts of infor-mation theory continued to be refined (Stone 1960; Bertelson 1961), to take into account effects of sequential probabilities among stimuli in tasks which required serial choice responding. Further modifications to the theory were necessitated by findings which demonstrated that the time taken to respond to displayed information depended to a large extent on the compatibility between stimulus and response (Broadbent and Gregory 1965a) and upon the discriminability of stimuli (Rabbitt 1963). Conrad (1962) also showed that the linear relationship which had earlier been found between response time and displayed information was drastically altered by prolonged practice at a task. Morton (1964a) found similar inadequacies in the application of information theory to word recognition, which led him (1964b) to develop an alternative model for language behaviour. (Morton also contributed a series of influential papers dealing with suffix effects in short term around this time and introduced the concept of Precategorical Acoustic Storage – Crowder and Morton, 1969).

Signal Detection and Monitoring Increasingly the idea was being adopted that perception did not involve stimuli being either definitely received or definitely missed, with no intermediate category (Broadbent and Gregory 1963), but that the brain was making a statistical decision when detecting signals from the environment. Perception was seen to depend upon two important factors: the strength of a signal relative to the noise within the perceptual system, and the perceiver’s expectancies about the probability of appearance of signals and ‘non-signals’. As Broadbent and Gregory (1965b) showed, these factors can be affected differently by changes in the conditions under which work is performed. This finding has an important practical consequence for evaluations of man-machine systems which involve monitoring, because it is no longer sufficient simply to measure the errors a man makes. One also needs to assess the effects of working conditions on the man’s expectancies and the way that changes in these expectancies alter his decision-making criteria. Later advances in signal detection theory showed that these changes in criteria might be measured by recording the level of confidence with which a man reports his decisions. The theory predicted that shifts in confidence could result in large changes in the number of signals correctly detected, for relatively small changes in the number of false reports. Colquhoun (1967a) was able to verify this prediction, from measurements of performance on a task of sonar target detection. Broadbent (1967) pointed out that it is also a higher level of confidence which produces greater efficiency in reporting probable, rather than improbable, words heard on a noisy telephone line. This effect is clearly important to the design of articulation tests and to the construction of special vocabularies for use in noisy conditions.

Environmental and Task-induced Stress For a number of years a considerable proportion of the Unit’s research was directed at evaluating the effects of various stresses upon working efficiency. It was during this period. for example, that the Unit’s work on card sorting at altitude – 19,000 ft up Everest was reported in Nature (Gill, Poulton et al, 1964). Throughout the 1960s, and especially with the acceptance of ‘arousal’ theories, systematic studies of interactions between stresses began (Wilkinson 1963). In a review of some of these experiments, Broadbent (1963) argued that it was no longer legitimate to think of a single mechanism mediating reaction to stress. Effects of heat appeared to be independent of those resulting from noise and sleeplessness, and the latter two stressors seemed to have effects which tended to cancel each other. Incentives, on the other hand, were found to increase the harmful effects of noise (Wilkinson 1963). The practical implication was that one could no longer regard any particular environmental condition by itself as detrimental to performance, without regard to the nature of the task being carried out under that condition. This attitude affected the methodology adopted in studies of real-life stresses. A need was seen for the development of simple tests, designed to be sensitive to specific environmental conditions. Thus Baddeley and Flemming (1967), for example, developed a test of manual dexterity which showed that breathing an oxy-helium mixture at pressure substantially improved the accuracy of divers working 61 m (200 ft) down, as compared with others breathing ‘pure’ air.

Post Office Studies With Dr Conrad’s appointment as Human Factors Consultant to the General Post Office, a range of problems was dealt with which derived from the need to design communications systems capable of being used efficiently by the majority of the general public. The differences between this range of problems and the more conventional subjects of industrial and engineering psychology have been reviewed by Conrad (1967a). Current research on stimulus-response compatibility, on the role of letter-sequence redundancy in short-term memory and on the conditions for effective recall of letters and digits, was used to advise the Post Office on the design of alpha-numeric postal codes (Conrad 1967b). Research on memory and on stimulus-response compatibility was also used to advise on the design of data-entry keyboards for telephones (Conrad 1966) and for semi-automatic letter-sorting machines. Techniques for measuring recognition memory for words were used by Rabbitt (1966) to study the efficiency of communication over noisy channels.

Conrad’s (1963,1964) research on acoustic confusions in memory also had important practical consequences for the design of communications systems. He showed that when people had to remember visually presented verbal material for brief periods before making a response, their errors resulted from confusions between items in the stimulus vocabulary which sounded alike, rather than between those which looked alike. This implies that designers of visual displays should ensure that signals not only look different from one another, but that the names people give them will also sound different. This is especially important in displays of alpha-numeric material. Car Driving Increased attention was also being given to another skill which was involving more and more of the general public: that of car driving. The emphasis here was on studies of conditions likely to cause impairment of skill, such as prolonged driving (Brown et al. 1966) or using a mobile telephone (Brown et al. 1969), and on techniques which might be used to assess effects of training on individual differences in driving skill (Brown 1968a).

Tracking Control Skills Training for control skills in tracking was also under investigation. The problems of simulator training were given special attention (Hammerton 1966) and doubt was cast on some assumptions previously underlying the design of simulators. For example: in training people on remote control of distant objects it appeared that simulation of the actual physical situation was much more important than simulation of the angular dimensions as projected on the operator’s eye (Hammerton 1963; Hammerton and Tickner 1967). The implication was that one could not expect immediate and perfect transfer of training to the real situation when men had been trained on, say, CRT displays. Many of the cues which allow us to perceive spatial relationships are clearly absent during CRT simulation, which prevents perfect acquisition of these remote-control skills, even with prolonged training. Further synthesis of the factors involved in tracking were reviewed in Poulton (1969). Physiological Rhythms and Shift Work In the mid-sixties a new interest was taken in the physiological correlates of behaviour. In particular, research was aimed at the effects on performance of physiological changes related to time of day (circadian rhythms). This work was being developed by Mr M. J. F. Blake, just prior to his accidental death in 1965. Blake’s data were prepared for publication by Dr Colquhoun (Blake 1967a, 1967b), and produced two important results. Firstly, performance on a wide range of tasks was shown to bear a close relationship to diurnal fluctuations in the man’s physiology, as measured by body temperature. Secondly, a significant difference in the phase of the diurnal rhythm of temperature was found between people with extreme high and low scores on the unsociability scale of the Heron Personality Inventory.

As Colquhoun (1967b) has pointed out, there are practical implications here for the design of rotating shift systems, since these temporarily disrupt a person’s diurnal rhythm of activation. The findings are also relevant to the selection of personnel best able to operate those shift systems efficiently. Wilkinson and Edwards (1968) have shown that the most important factor in designing work schedules is to stabilize daily shift times, i.e. arrange that a shift occurs continually at the same time of day or night in each successive 24-hr period. This procedure allows people to adapt to working and sleeping at unusual times, with a subsequent improvement in performance, as compared with, say, a weekly shift system, where the man on night shift is just beginning to adapt, physiologically, when he has to revert to day work. This area of research is also of methodological interest to anyone investigating prolonged performance of tasks, since account must be taken of possible interacting effects of time-on-task and time-of-day (Brown 1967). Design for Everyday Life Closer links between Britain and Europe during the past few years have renewed concentration on the problems of designing systems which affect all members of the general public. With the growth of international telephony the public has been forced to use telephone numbers which far exceed the normal memory span for digits. Information has had to be produced on the best methods of dialing or copying these long sequences, e.g. by grouping them in various ways, and on the layout to be used when they are printed in directories, etc. (Conrad and Hull 1969). The design of printed information itself has come in for a good deal of attention (Poulton 1969d) to meet the need for conveying written information rapidly and effectively.

The decision to convert our currency to the decimal system by 1971 also produced its problems for the general public. New shapes and sizes of coins had to be introduced, and Wright (1969a) with others (Wright, Hull and Conrad 1969) compared the merits of some alternative shapes from the point of view of visual and tactile discrimination. Wright and Fox (1969, 1970) also compared performance on the various types of conversion tables which would be needed with the new currency. New decimal postage stamps had to be designed, and Brown and Hull (1971) evaluated the confusability of the colours used within the new range.

Changes in other systems will produce problems for the human operator. For example, with the spread of motorways it becomes increasingly difficult for the police to monitor traffic for offences and accidents. One solution is the greater use of surveillance by closed-circuit television. This raises questions on the best way of arranging the monitor screens so that the displays from a large number of cameras beside the road can be watched efficiently and incidents reported with minimum delay. Tickner and Poulton (1968) have published some initial findings on these queries.

Personnel and Publications

The number of APU staff varied rather little up to the late 1960’s. Some expansion came with new accommodation added to the main house. By 1972/3 the annual Human Performance Reports listed 27 scientists (with some overlap between leavers and starters), 25 research support staff and 9 administrative and secretarial support staff. The staff were producing around forty to fifty papers annually in scientific journals and other outlets, reflecting the balance between the Unit’s applied and academic interests and the diversity of special interests among APU staff: in problems of ageing, deafness, skin diving, etc.

Broadbent resigned the Directorship at the end of September 1974. At this point he moved to the Department of Experimental Psychology at Oxford where he continued his own research programme into selective and control processes in perception and memory as a member of the MRC’s external Scientific Staff.

The Baddeley Directorship 1974 to 1994/7

The Period of Alan Baddeley’s directorship, being the most recent of those covered here, is the naturally the one for which we have the most amount of information available and of course, most of the participants in the meeting will have worked at APU in this period. Apart from the major scientific developments that came over these years the reporting demands also increased. As a rough guide the 8 page progress report for 1954-60 with ten pages of references was a mere shadow of the 400 plus page report and proposals submitted in 1994, where the table of contents alone covered 10 pages. As background reading for the period and to remind us of things they might well have forgotten, we simply append here the Director’s overviews for the periods 1974-78; 1978-81; 1981-84; 1984-89; and 1990-94. Across this period there were a series of changes in “topics covered,” and obviously in the personnel involved. Those doing the work are not always identified by name in the first few overviews. Throughout this period, the network of national and international visitors and collaborations continued to strengthen. The 1978 report lists around 48 research and technical staff plus a number of what were then called “attached workers” which included visitors and grant-supported post-docs, and eleven PhD students are listed. The 1994 report lists 137 research and technical staff again plus attached workers and administrative staff. There were 34 visiting scholars and 15 MRC scholars listed in that report. The 1994 progress report also lists 27 externally funded contracts for that review period. While these included three projects funded by the US ONR and US AFOSR and our own Defence Research Agency, the larger proportion of externally supported research derived from National, European and charitable agencies.

Directors Overview: Progress Report for the period 1974-78

I regard the Applied Psychology Unit’s primary role as providing a bridge between the experimental psychology laboratory and practical problems. If we are to fulfil this role we must be able to produce both theoretical work of a high order, and usable practical answers to immediate problems. While such a combination would not be possible in many subjects, the current position within psychology is such that the combination is not only possible but is a very fruitful one, a conclusion which is I think supported by our publications, and by the continuous stream of requests for advice and assistance that we receive.

The range of applications of our work is very wide, and in describing it there is a real danger that the diversity of practical applications will obscure the underlying theoretical concepts which link the many and varied applied studies. A relatively straightforward example of this is the unit’s psychoacoustic work, where a single theoretical concept, namely that of an acoustic filter within the auditory system, motivates a range of applied questions including the design of auditory alarms for detectors of chemicals, warning systems for aircraft pilots, methods of audiometry and the design of hearing aids. A similar situation obtains in our work on cognitive psychology, but is less obvious since the underlying theoretical models are more complex, and frequently use somewhat different terminology to refer to broadly similar concepts. Hence Morton’s logogen system which was devised to explain context effects in perceiving words has much in common with Baddeley & Hitch’s working memory model which was originally designed to study the role of short-term memory in such tasks as reasoning, learning and comprehension. Both have similarities with the concepts developed by Marcel in order to explain his results on conscious and unconscious components in reading. All three approaches are closely related, and provide the basic concepts and techniques for tackling a range of problems which might at first glance appear to have very little in common. Hence the unit’s work on arithmetic, on reading, on man-computer interaction, on the design and use of pictograms and on amnesia and dyslexia, all draw heavily on a single coherent underlying approach to human cognition.

Many of the new developments within the unit over the last 3/4 years have stemmed from the attempt to confront this underlying theoretical commitment to cognitive psychology with tractable applied problems. The most obvious application of cognitive psychology is within the area of education, and in the proposals I made in applying for the Directorship of the APU this is the area in which I suggested we should develop. The Board subsequently indicated that such a development was not appropriate, given the Council’s general remit, and consequently this led to a rethinking of the possible fields of application. The result has been a concentration on the cognitive skills of adults rather than children, with a developing interest in the application of our skills and techniques to the problems of clinical psychology, and in particular neuropsychology.

In recent years, neuropsychological work has had an increasing impact on theoretical issues outside the clinical sphere. Hence work on patients with defective long- or short-term memory has played an important role in the development of general theories of memory, and information from patients with reading difficulties following brain damage has contributed substantially to our understanding of normal reading. We have over the last four years built up a very fruitful relationship with colleagues in neuropsychology in London, Glasgow, Paris and Oxford, which has led to profitable collaborative work. In the meantime we have been slowly building up our contact with Addenbrooke’s hospital to a point at which we now have excellent links with the speech therapy department where we are carrying out work on aphasia and dyslexia and on evaluating methods of speech therapy, with the EEG department where Wilkins is doing collaborative work on photosensitive and TV induced epilepsy, and with the department of neurology and neurosurgery where we have recently set up a project on closed head injury. Perhaps the most important feature of our recent developments is that we are extending our interests beyond the intensive study of a very few cases selected because they appear to have a very pure defect, to the consideration of much larger groups of less clearly defined patients. For example, head injured patients are unlikely to allow the precise testing of particular models which are provided by the rare “pure” amnesic or dyslexic. They do however present a practical problem of much more immediate significance, since they are vastly more numerous and present a substantial rehabilitation problem. They represent a theoretical challenge in requiring us to study very closely the relationship between our laboratory based tests and the ability of the patient to cope in the outside world; I would be surprised if this did not, for example, lead to a re-evaluation of some of our views on human memory.

An area of cognitive psychology that continues to be a major APU interest is that of the design of information, how one should present information so as to make it most easily understood. It has the great advantage of confronting psycholinguistics, an area of considerable theoretical activity, but somewhat subject to the dictates of fashion, with a very down-to-earth practical problem such as that of attempting to help a person fill in a social security form correctly. The result has been a combination of steady theoretical development coupled with a capacity for providing advice and assistance across a very broad range of practical situations. The most recent development in this area is our work on man-computer interaction where current developments suggest that very shortly the general public will be increasingly encouraged to interact directly with computers.

As anticipated, the unit’s work on perception has slightly declined. With the decrease in our involvement with work for the Royal Navy, the projects on computer-assisted detection, and on coloured displays have both been terminated. We are however continuing to do work on recognising people, while the recently approved project on accident causation includes a proposal to study perceptual style. The area of psychoacoustics is flourishing. We have developed new technical facilities and undertaken a range of projects involving auditory warning systems, audiometric assess-ment and evaluation of hearing aids. 1 would expect this aspect of the unit’s work on perception to continue to develop. There might also be some advantage to strengthening the unit’s work in the area of speech perception, an area of traditional strength at the APU which is perhaps less vigorous than formerly, and which would provide a very useful link between our psychoacoustic work and our more cognitive work on language.

A substantial involvement in the area of motor skills continues. In the past this work has focussed mainly on keyboard design and on tracking performance. Both of these continue although they form a less important component than previously, partly because the immediate practical problems that stimulated earlier work have now been solved or bypassed. Work is however continuing on the classical problem of combining two or more skilled tasks, and a new line of research on the skill of handwriting is proving fruitful at both a theoretical and applied level. It is perhaps worth noting the link between the unit’s motor skill work and its work in other areas; hence the work on keyboards ties in rather well with studies of man-computer interaction, particularly where naive users are involved; work on dual task performance ties in very closely with some of the techniques and concepts developed in studying attention and working memory, while the study of handwriting is related to both speech production and memory through questions of mechanisms for maintaining sequential order. Another of the unit’s traditional interests which continue to flourish is work on the behaviour of drivers. A good deal is now known about the manual skills involved and we are now more concerned with the more cognitive perceptual and indeed social factors. This has led to an interest in driver attitudes as well as skills, and to an extension of the work of Brown’s group beyond that of driving to an interest in accidents more generally, and in particular to the psychological factors preceding accidents. Additional resources have been given which will extend the unit’s work in this general area. For many years, the unit has had a very active interest in the influence of environmental stress on performance. Our involvement in this general area has continued but at a relatively low level over the past four years. This was partly because the group of people interested in stress was split between the main unit, the Psychophysiology Section and the outstation at Sussex (now the PCPU). The fact that we no longer have naval rating subjects also makes stress work more difficult to arrange; this in turn reflects less preoccupation with environmental stress by the Navy who sponsored most of our earlier work in this area. There are however signs of a revival of interest from both the Navy and the Army, and I would be happy to see us attempt a more systematic and theoretically based approach to the general problem of measuring human performance. I would like to see it moving in the direction of turning what is at present a craft into a technology which would be at least as important within the clinical field where the problems of the assessment of patients with a view to either prognosis or evaluation of rehabilitation technique! is likely to be increasingly important.

There are also signs that theoretical interest in individual differences within the general field of cognitive psychology is growing, and this should help provide a more satisfactory theoretical basis for work on neuropsychological assessment. In the long term, it is clearly desirable that the technically sophisticated but theoretically sterile approach to individual differences which underlies the intelligence testing tradition be replaced or at least supplemented by an approach which is more concerned to elucidate the processes underlying differences in performance. I would see our work on the cognitive effects of stress and of brain damage as contributing to this general long-term aim. The unit continues to be very actively involved in providing advice and occasionally assistance across a very wide range of problems. Our heaviest single involvement is with the Post Office for whom we continue to provide both ad hoc advice and a good deal of experimental work on both immediate and long-term problems. We tend to be contacted a good deal by the Press and television both about our own work and for advice on other issues. In general we welcome this since we regard part of our function as helping to provide a reasonably accurate channel of information between experimental psychology and the general public. Such a flow of information also brings us queries of a more substantial nature, some of which lead to experiments and ultimately research projects. We regard this flow of practical problems as a crucial element in our particular approach to psychology.

The Psychophysiology Section has just passed through a rather disrupting period with the installation of a new computer and the long delayed extension and re-organisation of available space. During this period collaborative work with various outside bodies on measuring performance under stress continued, as did the development of portable apparatus for performance monitoring. The new facilities are now fully operational, and work is in full swing on a series of projects on sleep. The most extensive of these is a CEC project in collaboration with a number of European laboratories which is aimed at monitoring sleep in the home and relating both quality of sleep and performance next morning to environmental noise levels. A study on the verbal ability of deaf school leavers carried out by Conrad and his group at Oxford has now been completed. Virtually the entire population of such children were tested on a range of cognitive tasks, and has been analysed; some preliminary results have been already published, but the main publication will be in the form of a monograph which is nearing completion. It seems likely that the results obtained will be of considerable significance both for the light that they will throw on the current systems of educating the deaf, and also for their theoretical implications for the understanding of normal cognition.

Output note: The progress report for 1974-78 covered work published in some 227 papers.

Directors Overview: Progress Report for the period 1978-81

The Unit attempts to bridge the gap between pure and applied psychology. The theoretical concepts and experimental techniques developed through pure research often allow us to view applied problems in new and productive ways.. At the same time, the attempt to apply theoretical concepts outside the laboratory highlights the strengths and limitations of such concepts and in many cases leads to their further development and elaboration. We are fortunate in that cognitive psychology is at a stage of development where such an interaction between theoretical and applied research is both tractable and fruitful.

Over the past three years we have tackled a wide range of applied questions ranging from auditory warnings on the flight deck of civil aircraft to analysis of the job of the deep sea diver, and from the reading problems of brain-damaged patients to the speed of reaction of test cricketers. What ties together these apparently unrelated problems is a relatively limited set of underlying theoretical concepts. In general, the theoretical style of the Unit is to assume that cognitive behaviour reflects the operation of a number of subsystems, and to use experimentation to analyse such systems into component parts. Such an approach lends itself to clinical application in the area of neuropsychology, and over the last three years this has been one of the areas of greatest activity. Our approach however has been to use data from the breakdown of cognitive function in the brain damaged patient in order to understand normal cognition, and vice versa. We are not therefore a neuropsychology unit, we are an experimental psychology unit using and influenced by neuropsychological evidence. This will I hope become evident in the account which follows.

A characteristic of our work over the last three years has been an increased involvement in field experiments of a more long-term and ambitious nature than has previously been common at the A.P.U. Examples of this are the work on evaluating techniques of speech therapy, the project on individual differences in accident liability, the work on memory problems following closed head injury and the very extensive series of experiments on man-computer interaction. Most of these projects are still in progress, and it is in the nature of such long-term field research that results tend not to be obvious until the end of the project. However it is already clear that such research is providing a necessary and productive supplement to the Unit’s more traditional laboratory-based approach to applied research. While experimental work under controlled conditions will remain the backbone of the Unit’s approach, I would see field work as an essential part of the future work of the Unit. In general, the last three years has involved a development and expansion of existing work rather than a radical change in direction. The Unit’s work on audition provides a good illustration of this. The theoretical analysis of auditory masking in terms of an auditory filter has been refined mathematically and extended to include a wider population experimentally. Two major applications of the model have been developed:

(a) the design and evaluation of auditory warning systems for the flight decks of civil aircraft, and (b) the audiometric assessment of patients. In this latter area, the pre-liminary work relating filter shape to age is nearing completion and collaborative clinical research (with the Institute for Research into Hearing and Deafness) is about to begin. Visual attention is an area of current theoretical interest which is beginning to influence our applied research in clinical contexts and in connection with accident causation. Also in a clinical context is the work on photosensitive epilepsy: in addition to practical implications, for example in connection with T.V. induced epilepsy, attempts to locate the triggering mechanisms within the central nervous system are proving highly successful, while work on the spread of excitation within the cortex appears to have considerable promise in connection with a general model of epilepsy. The study of perceptual motor skills combines a focus on precise models of the underlying processes with a determination to apply such models outside the laboratory. Examples are the theoretical and applied studies on handwriting and the successful application of laboratory-based theory to an analysis of the highly developed skills of the test match cricketer. The area of greatest current development however is probably in the study of movement patterns in clinical populations. The neuropsychology of movement is a relatively unexplored area, and one to which we hope to devote an increasing amount of effort over the next few years. In the area of stress, research on performance has largely consolidated previous work, using both portable test equipment and paper and pencil tests to look at a broad range of stresses. A major de-development over the last few years has been in the Unit’s increasingly sophisticated techniques for physiological monitoring in the field. The Psychophysiology Section’s work on noise and sleep in the home is an example of this, as is the work on telephone switchboard operators and the project on trainee parachutists.

The psychology of memory continues to be an area of vigorous development within the Unit. In the area of short-term and working memory, previous conceptual developments have been expanded and applied to new tasks such as reading and arithmetic. In long-term memory the major trend over the last few years has been an attempt to test, in the field, the generality of the extensive laboratory-based research on human learning and memory done over the last ten years. Examples of this are the head injury and memory project, work evaluating saturation advertising and work on memory lapses in everyday life. Existing theories of memory tend to be ill equipped to cope with the richness of this type of data, and one of the most recent developments within the Unit has been a growing concern to develop theories of long-term memory which are capable of reflecting this degree of complexity.

The area which has probably seen the most vigorous activity over the past three years has been the study of reading. In particular, there has been a great deal of interest in relating the patterns of reading disorders resulting from neurological injury in adults to the dimensions and variables which affect the reading performance of normal adults. Deep dyslexia, a syndrome which appears to be particularly pertinent to current models of normal reading, was the subject of an M.R.C. sponsored conference held in Cambridge, and a book in which six of the chapters were written by members of the A.P.U. Three other syndromes of acquired dyslexia have been receiving increased attention in the last year or two, and seem likely to prove theoretically very productive. I would see this line of research continuing and broadening to include an increased involvement in the study of aphasia, a topic addressed mainly over the past three years by a successful applied clinical project to evaluate speech therapy techniques for facilitating word finding in aphasic patients.

Work on design of information and factors influencing the readability of forms and tables has continued to flourish. The major focus now is to communicate our results to the enormously wide range of potential users, in a way that allows them to implement recommendations effectively. In this respect, it is obviously much more desirable to formulate principles that will assist good initial presentation of material rather than simply provide techniques for identifying the flaws in what has already been produced. We are therefore starting a programme of research on the factors involved in good writing.

The most active current area of applied research in the Unit has been in the field of man-computer interaction, where we can cope with but a small proportion of the requests for research that we receive. Again we have been concerned to develop general principles designed to allow a user to tackle this important area himself, rather than solutions to specific limited problems. While we are clearly making progress, it is obvious that this area is sufficiently complex and important to justify substantial future Unit involvement.

The project on individual differences in accident liability is now well advanced. A battery of tests of both perceptual and attentional performance has been developed and is currently being used in a prospective study of accidents in London Transport bus drivers, At the same time the Transport and Road Research Laboratory and the R.A.F. are collaborating by testing samples of accident-involved motorists and trainee pilots. While we can obviously not at this stage predict whether the tests will prove appropriate, I think we have demonstrated that such an approach is both feasible and sufficiently attractive to outside bodies to induce them to commit considerable assistance to the project. I would therefore like to suggest that the Board should approve the designation of this area of research as an established feature of the Unit’s programme, thereby allowing its continued development.

The main emphasis of work at the Psychophysiology Section has been on the study of sleep in the home, in response to an increase in extramural support for this topic. It has been shown that traffic noise can have a major effect on the sleep of people living near arterial roads, an effect which is reflected in their test performance next morning, but which can be alleviated when noise level is reduced by double glazing. Other work has concerned the sleep of shift workers and their subsequent performance. Work on portable apparatus for assessing deterioration in skill has continued, with the development of two new tasks, vigilance and short-term memory, while performance has been studied under a range of stressors, including noise, anaesthetics, antihistamines and industrial pollutants. Work at the Oxford Outstation on the cognitive abilities of the deaf is nearing completion. A major monograph on the project has been published and extremely well reviewed. A study of the deaf children of deaf parents is nearing completion. It tests the hypothesis that extensive use of sign language during the child’s early years will allow more normal cognitive development than occurs when deaf children are exposed only to spoken language.

The Unit was invited to host the ninth meeting of the International Association for the Study of Attention and Performance — the first to be held in Britain. We departed from the normal procedure of a single organiser, spreading the load of both organising the meeting and editing the proceedings widely throughout the Unit. This seems to have proved a successful policy; comments on the organisation were uniformly positive, while the proceedings (120 U) are on schedule to appear in half the time taken by recent volumes.

The Unit continues to play a very active consultant role, responding to an average of 45 requests per month for information and assistance. A substantial minority of these are requests for advice or information from the Press, radio or T.V., and while we are often able to do no more than suggest an appropriate further contact, we do regard our relationship with the general public via the media as being of some importance. Presenting psychology in a responsible but stimulating way is part of our job, and, in addition to writing articles and contributions to semi-popular books. Unit members have recently been involved in at least three radio and eight television programmes, the latter comprising mainly popular science programmes of the “Horizon” type. The Unit continues to provide advice and assistance to a wide range of outside organisations and individuals on issues where the techniques of applied psychology are relevant. This often leads to a continued involvement in either an advisory or a collaborative capacity, something which we welcome because it allows us to extend the scope of our work in new areas, while tending to keep our theoretical feet firmly on the ground. I would see such activity continuing to be an important component of the Unit’s work.

Output note: The progress report for 1978-81 covered work written up in some 307 papers.

Director’s Overview: Progress Report for the period 1981-84

Much of the Unit’s theoretical work falls within the area that could loosely be called mainstream cognitive psychology. This includes work on memory, language, reading and reasoning, together with the breakdown in these functions in neuropsychological patients or patients suffering from psychiatric or emotional problems. The concept of working memory, for example was originally developed within the laboratory using normal subjects to study the temporary storage of information in connection with other cognitive tasks. It has subsequently been extended to account for data from neuropsychological patients while the model is providing a useful framework for studying problems ranging from normal and dyslexic reading, to disruption of memory by unwanted sound and from memory for music to senile dementia. Much of the Unit’s work in long-term memory is concerned with research outside the laboratory, although this often has theoretical implications. A good example of this is our research on eyewitness testimony which has produced results which have both practical implications for the questioning of witnesses, and theoretical implications for the nature of the underlying memory trace.

In our last progress report we stated an aim of increasing the Unit’s work in the area of language and speech, and have succeeded in doing so. Prosody and the role of stress and timing in speech production is a particularly active area at present; work in this area has considerable implications for computer-based speech processing, and collaborative work includes two projects funded by British Telecom and participation in an Alvey-sponsored project as part of a consortium that involves the Linguistics and Engineering departments of the University together with Acorn Computers and Standard Telephone and Cables.

Research on reading and writing continues to play an important role in the work of the Unit, and work on the breakdown of these skills in brain damaged patients is continuing to prove extremely fruitful. The principal strategy is still to attempt to relate the breakdown of function in patients to models of normal cognition. The emphasis has shifted somewhat from deep dyslexia which was the most extensively studied deficit described in the previous progress report to surface and phonological dyslexia, and to deficits of writing and spelling.

The Unit is continuing to play a very active role in the development of cognitive theory. Johnson-Laird’s mental models approach is clearly likely to be highly influential, while the Unit continues to have an active interest in the application of artificial intelligence to cognitive psychology. Unfortunately however this is one area that, despite its timeliness and importance, is unlikely to continue to flourish unless up-to-date computing facilities can be made available.

A major new development has been the attempt to apply the techniques of cognitive psychology to clinical problems of patients with psychiatric and emotional problems. The Unit has formed excellent links with NHS clinical colleagues, and is carrying out research on a range of populations, some involving patients such as depressives or suicide attempters, others using subsamples of the general population with milder emotional problems such as spider phobia, excessive worrying, or loneliness. Preliminary results indicate that this is a viable enterprise both logistically and scientifically. The speed with which this small group has established itself, and its success in interacting with both clinical and cognitive colleagues is very gratifying. A central component of the Unit’s work involves the application of cognitive psychology to the tackling of practical questions, an area which could loosely be termed Cognitive Ergonomics. The development of new computer-based technology raises many problems of relating the computer to the human user, and on a world-wide basis is certainly the major growth area of applied psychology. Having worked in this area for over a decade, the API) is in a good position both to attract outside support and to ensure that its findings reach the potential user.

Much of our work has been concerned with the development of computer-based office systems, where ease and efficiency of use depends crucially on taking account of the user’s “mental model” of the system, which will almost certainly differ radically from the mental model of the expert computer scientist who created the system. Similar problems occur in the design of programming languages, in the organisation and structure of information retrieval systems such as Prestel and Viewdata, and in the design and development of expert systems.

Expert systems attempt to take the information possessed by an expert in a particular field, and embody this in a computer-based system. While the computer science techniques are advancing rapidly in this area, a crucial stumbling block is likely to be the problem of how to “harvest” an expert’s knowledge, a question closely related to the psychological problem of exploring an individual’s semantic memory. Research on this important but difficult topic is beginning, in collaboration with British Telecom, and with Unilever.

We are continuing to carry out work on more traditional methods of information transmission, witn ongoing research concerned with the design of forms, tables, leaflets and instructions, all topics on which we are frequently asked for advice and assistance. A new development in this area is our attempt to move from the identification of problems in written material to an exploration of possible methods of improving the quality of writing so as to avoid the occurrence of such problems. The project concerned with accidents has completed one cycle of research and is beginning a second. The phase that is virtually complete involved investigating claims that particular psychological variables were predictive of future accidents. Studies included work on bus drivers and pilots, and the measures included both field dependence, the capacity for perceiving a pattern against a jumbled background, and an attentional flexibility measure. Neither proved adequate predictors. At a theoretical level two influential concepts, that of risk homeostasis, and that of perceptual style have been critically evaluated and related to the problem of accidents.

Another application of cognitive psychology is to the monitoring of human performance under stress. Both the main Unit and the Psychophysiology section continue to be concerned with the development of tools for assessing performance, and in recent years these have been applied to the effects on performance of the fear induced in novice parachutists, and novice colloquium speakers, to the effects of breathing mixture on deep divers, to studies of noise, sleep deprivation and to the side-effects of drugs.

Research in the area of hearing has been very successful over the last three years. It may be recalled that work on the discrimination of sounds in noise gave rise to a detailed model of the auditory filter. This was then used both to produce improved audiometric techniques, and to design auditory warnings for specific environments. Guidelines for the design and evaluation of auditory warnings have been produced for the Civil Aviation Authority and warnings have been produced for the BAC 1-11, the Boeing 747 and for military helicopters. The work has been patented and has so far generated some £20,000. Current developments include the application of this research to the production of international standards for auditory warnings in hospitals. A potentially extremely important development from this research is the spiral model of hearing. This involves the proposal of a spiral mechanism for the rapid and accurate categorisation of sound patterns. The model accounts for the characteristic features of musical perception, and has the further advantage that it offers an extremely promising design for a computer-based speech recognition system. The system has been patented with the help of the Industrial Liaison Group, and a venture capital company has agreed to fund its development. In view of the magnitude of the potential market for computer speech recognition, this could be an extremely important development theoretically, practically and financially. A new area that is emerging at the Unit is that of research on music. Not only does this offer a useful preliminary test of the spiral processor model, but it also provides an interesting complement to the Unit’s extensive interest in speech and language. Hence the parsing processes involved in language production find their counterpart in processes underlying musical improvization, while the similarities and differences between the perception of music and speech have interesting implications for the nature of the underlying perceptual system. Research on music also ties in neatly with work on memory, and research on timing and rhythm in motor performance. Research on motor skill and action is however, rather less strong than three years ago, with the retirement of Poulton and the departure of McLeod to Oxford and Grudin to the U.S. computer industry. On the other hand, research on the disruption of movement by brain damage, and its subsequent recovery has flourished in the last three years, and seems likely to continue to be an important component of the Unit’s work. Our interest in handwriting also continues and has reached a point at which it is beginning to spin-off valuable applied results, particularly in the area of forensic science and signature verification. Collaborative work on children’s learning of handwriting is a new departure which also seems promising.

An area which has shown signs of increasing in strength since the last progress report is that of visual perception, an area that has been greatly strengthened by the appointment of Matt who will combine a strong theoretical interest in vision with a concern for the applications of vision research to the area of driving and accidents. Work on visual attention continues to be strong while an interest in the relationship between perception and action is shared by a range of scientists who would not describe vision as their primary area of concern.

Application of psychological techniques to the study of photosensitive epilepsy has continued to be profitable, and has produced a very interesting further development. Those patterns that are most likely to induce photosensitive epilepsy are also most likely to induce illusory shimmering and colours in non-epileptic subjects, and to be most strongly associated with reports of eyestrain and headache. This relationship is being extensively explored and may have important implications not only for the understanding of eyestrain and headache, but also for the design of computer visual display units, fluorescent lighting, and even the optimal spacing of lines of print on a page.

The Psychophysiology Section has continued to be particularly active in research on sleep. An EEC supported project on the effects of traffic noise on sleep is nearing completion. It involved developing techniques for studying sleep in the home, and yielded the interesting finding that for most of the subjects studied, the measures of performance proved to be a more sensitive indicator of the deleterious effect of noise on sleep than did physiological EEG measures, although a small subset of subjects does appear to show clear physiological response to outside noise. Traffic noise appears to prevent the sleep of such people reaching its normal depth, suggesting that in the long term their health may potentially be put at risk by the requirement to live under noisy conditions.

Research on shiftworkers also revealed interesting and potentially important effects. Night-shift workers’ day-time sleep shows a clear decrement in both amount and quality. Psychological performance also shows steady deterioration over successive days, suggesting that shiftworkers may suffer from progressive sleep deprivation during a week on the night shift.

The section’s work on developing portable tests has proved valuable with over 400 of their instruments being bought by establishments wishing to monitor performance. The section’s own work on performance monitoring has ranged through the more traditional areas of detecting the effects of drugs and investigating noise effects to a field study of the influence of human behaviour on the control of domestic heating, a study with obvious implications for energy conservation. Developments in microprocessor technology have made possible several applications in relation to timing of responses and logging of analog data. This means that various forms of experimentation are now readily portable and reproducible at low cost. Examples include Norn’s tachistoscope program; Bloomfield’s Clocks for the BBC micro; Wilkins’ eye-movement studies; Wing’s studies on force and timing in motor control, and Nimmo-Smith’s work on handwriting. The accumulation of expertise in applications of microprocessors is yielding increasing returns. It shows promise of meeting the extensive educational and clinical demand for cheap but sophisticated means of testing functions and monitoring progress. In conclusion, the Unit continues to use a coherent and interconnected set of concepts and techniques to tackle a wide range of applied questions. This appears to be a fruitful strategy, both in yielding results of practical value and in testing, enriching and developing the underlying theories.

The progress report for 1981-84 covered work published in some 465 papers.

Director’s Overview: Progress Report for the period 1986-1989

The Applied Psychology Unit aims to operate at the interface between psychological theory and practical real-world problems. We believe that this is theoretically fruitful in testing the validity of theory and extending its range at the same time as allowing psychology to be brought to bear on problems of practical importance. Over the 45 years of its existence, the Unit has developed a mode of operation that allows us to combine these two aims. It is however a somewhat unusual one, and is not reflected easily within the standard framework for a Council Progress Report. A typical progress report appears to describe a limited number of major projects, each run by a senior scientist who supervises a substantial team. The APU model on the other hand tends to be based on a relatively large number of individual scientists each of whom is unlikely to be supported by more than a single junior scientist or research officer. Furthermore, each scientist is likely to have several projects in different areas, often involving collaboration with other scientists within and outside the Unit. The Unit therefore comprises a complex network of interaction rather than a hierarchical structure of research teams. Figure 1 gives some indication of this, simply by linking by line Unit members who collaborate to an extent that has led to, or is likely to lead to joint publication. It does not, of course, reflect the much greater range of informal discussion and consultation.

What gives the Unit coherence is the common interest in a limited number of broadly related themes, together with the application of a range of broadly agreed techniques and concepts. We have since our inception tended to focus on the methods of experimental psychology, and use concepts of information processing broadly based upon the computer analogy. However, just as computers have developed considerably since 1944, so have the concepts and methods of cognitive psychology. We see our role, at least in part, as breaking new ground and extending psychological theory to areas that are hitherto relatively unexplored. Since the world is full of such areas, how do we choose? Our usual strategy is to attempt to identify areas that have the following characteristics: (a) potentially theoretically tractable, (b) of long-term practical importance, © sufficiently close to our current interests to ensure that investigators will not become intellectually isolated, combined with (d) our ability to find and attract a first-rate scientist interested in working in that area. We regard the last criterion as of outstanding importance; it is indeed probably the major factor in determining which of a range of possible developments we actually choose. Decisions about new developments, junior scientific appointments, and about the Unit’s views on senior appointments are all dependent on the Research Coordination Group (RCG). This is a Unit committee chaired by the Director, comprising the two Assistant Directors and Technical Coordinator, together with six elected members. These comprise four scientists, who typically tend to be senior members of the Unit, and one RO or technical member, together with one other member elected from junior scientific staff. Decisions are reached by consensus. The RCG meets monthly, or more frequently if there is particular need. It appears to work reasonably effectively, allowing issues to be discussed extensively, while very successfully maintaining confidentiality. We believe that our way of planning and running our research programme has been, and continues to be, very successful. It does however present problems when it comes to writing progress reports, where it is necessary to reduce this rather complex network of activity to a limited number of apparently separate projects. Consequently, the structure of each project tends to be rather diffuse with the assignment of a particular piece of work to one project rather than another being somewhat arbitrary.

That being so, it is easy to lose the main themes that run through the Unit’s work, and see it as a rather disconnected melange of mini-projects. For that reason, I will in this overview try to emphasise the underlying themes, albeit at the risk of blurring the distinction between nominally separate projects, information that can of course be obtained from the more detailed body of the Progress Report.

Summary of Research

Cognitive Neuropsychology

This is an area in which the Unit is particularly strong and active, suggesting that it should be covered in this overview. We have, however, opted to discuss the neuropsychological work of the Unit under the various topic areas to which it contributes, rather than as a separate topic. Anyone wishing to pick out this line of work should note the work on attention done by Burgess, Duncan, Marcel and Shallice, the “research on language, reading and writing by Marcel, Marslen-Wilson, Patterson and Shallice, and the research on memory by Baddeley, Gathercole and Shallice. Neuropsychological research on motor skills has been carried out by Wann and Wing, and in the general area of vision by Marcel and by Wilkins.

Attention (Projects 57-59)

The study of attention has been a major theme of the Unit’s work for many years, and it comprises three current project areas which form a good example of the points just discussed. Project 57 is concerned with visual selective attention, and is represented principally by the work of Duncan, who has developed and elaborated the theory that was first mentioned in the last Progress Report, and which is now about to appear as a major theoretical paper [13]. The model, developed in collaboration with Humphreys (Birmingham), has been extensively explored using the task of visual search, which has supported the importance of two concepts, namely a template reflecting potential targets, and the characteristic features of the range of non-targets. The model gives a good account of existing neuropsychological and neurophysiological data and Duncan will spend next year carrying out collaborative single-cell recording work on monkeys, with Desimone in NIH Washington, developing the neurophysiological aspects of the model. The possibility of linking neuropsychological and neurophysiological theory represents an exciting development in cognitive psychology, and one which I would expect to become more marked in future years.

A major focus of much of the Unit’s work over the last five years has been on Project 58 which is concerned with executive processes in cognition. These are so central and ubiquitous in cognitive psychology that it is tempting to place very large amounts of the Unit’s work in this category. For example, the concept of working memory which is concerned with the temporary storage and manipulation of information as part of more complex processing tasks, is clearly very much concerned with executive processes, and could equally well be categorised as research on attention as on memory. The study of the process or processes responsible for the attentional control of action plays a central role in the Unit’s work. Shallice has worked on this problem for a number of years, and his joint model with Norman represents one of the few available conceptualisations of the attentional control of action. This was incorporated by Baddeley into his general model of working memory. In the case of neuropsychological studies, Baddeley and Shallice and Duncan all share an interest in patients with frontal lobe damage, who appear to offer a possible clue to the operation of this system. Using such patients, Shallice and Baddeley have both observed an association between amnesia in frontal patients and confabulation, and both have drawn conclusions about the implications of this for the processes of normal retrieval. Duncan’s interest in the attentional control of action stems in part from his work on driving, leading him to an approach using dual-task performance, a route that has also been used by Baddeley in studying the role of working memory in complex skills such as chess playing and the acquisition of complex computer games. In future, Duncan and Baddeley plan to collaborate in using psychometric techniques to explore the relationship between the functioning of the controlling Central Executive component of working memory and older concepts of general intelligence. They plan to use individual difference measures and secondary task procedures, in a collaborative study with a U.S.

Air Force group concerned with fundamental research into individual differences. In addition to the above-mentioned work. Marcel’s demonstrations of the role of intention (in projects 68.3 and 68.4) are clearly aspects of executive function. In the first case the nature of an intended action seems to determine parameters of spatial representation, in the second case the nature of an intention seems to determine accessibility and fluency of motor control.

Given the parallels and similarities that are emerging from work in this area, it must be tempting to ask why the four groups have not worked together more extensively. The answer is that they were initially working on quite separate projects, Shallice on frontal lobe patients, Duncan on driving, Baddeley on short-term memory and Marcel on perceptual-motor control, all with adequate theories that appeared to be working quite well. The fact that these somewhat independent theories are now converging on broadly common and compatible conclusions is a point in their favour. Cognitive psychology is at present simply not in a state where detailed agreement on theory is a sensible prerequisite of a research programme. I would suggest however that the APU provides good evidence that cognitive psychologists with broadly compatible assumptions can work in a fruitful and cumulative way. Further evidence for this comes from Project 59 which is concerned with the analysis of the structure and functions of consciousness. This is clearly one of the most important but most difficult questions of psychology. Relevant work at the APU includes Marcel’s demonstration that information can be available to a subject and can be used without the subject being consciously aware of that information. He has continued to explore this area empirically, using the phenomenon of Hindsight, whereby patients with cortical blindness are able to make visual judgements about objects of which they report no phenomenological awareness. There has been a recent increase in the amount of activity concerned with the issues of consciousness, a development in which Marcel has played an important role. He plans in future to turn to the issue of awareness of bodily sensation, a topic that has been curiously neglected by psychologists, despite their considerable interest in the associated problem of pain. The role of conscious awareness in short-term or working memory is also an important but under-explored topic; the work by Teasdale on intrusive stimulus-independent thoughts, and by Watts and Levey on the role of such thoughts in insomnia, indicate that this area can be tackled empirically by using the very simple expedient of asking subjects at irregular intervals just what they are thinking about. Such simple but potentially useful thought-reporting methods will be used to extend existing models to explore the role of conscious awareness in working memory.

Audition (Projects 60-61)

This is an area in which a single very successful integrated group is now establishing much closer links with other aspects of the Unit’s work. During the past five years, the work on auditory warnings has continued to bear fruit, leading to a number of patents and British and International Standard specifications. Sets of auditory warnings have been delivered to the Civil Aviation Authority for civilian fixed-wing aircraft, and have been developed for three separate military helicopters, as well as being fitted in North Sea oilfield helicopters. Other applications include the development of an auditory warning system for hospitals (intensive care wards and operating theatres), and railway track-side crews.

Although this is an example of a very successful application of basic research in psychoacoustics, it also illustrates the potential danger of successful applied work, since our psychoacoustics section could spend its whole time developing alarms for the very many situations in which they are needed. Ideally, these projects would be taken on by industry; however our industrial partners typically do not have the necessary psychological expertise. An alternative is to delegate the running of the project to a junior scientist at the APU. In principle this is feasible, but unfortunately suitable psychoacousticians are few and far between, and once trained tend to leave for more lucrative jobs elsewhere.

Meanwhile Patterson has been actively developing a model of auditory sensation and extending it to the problem of speech recognition. This has led to his being the coordinator of a European funded ESPRIT Basic Research Action which involves collaboration between the APU and speech scientists from a range of disciplines and countries. Within the APU, the ESPRIT project will involve collaborative work on speech between a number of previously separate groups including that of Cutler and Norris on speech perception, Houghton and Shanks on connectionist modelling and Baddeley on phonological memory.

Language and Speech (Projects 62-64)

Although language consists of separable words, spoken language in fact comprises a virtually continuous stream of sound. This raises the problem of how to segment the incoming signal into separate words. Cutler and Norris in collaboration with Mehler and Segui in Paris have shown that this process differs between French, where the discrimination is based on syllabic units and English, which appears to rely on the tendency for English words to have their stress on the initial syllable. Cutler and Norris propose to test a number of models of this process, which is of course very important for attempts to develop devices for automatic speech recognition. As mentioned earlier, this will involve the detailed development of connectionist models of speech recognition, as part of the ESPRIT BRA project. The Unit has continued to be active in the study of reading and writing and their breakdown in dyslexia and dysgraphia. Detailed analysis of the reading deficit in patients who have become dyslexic following brain damage has been continued by Patterson, Marcel and Shallice. This again is an area that has been strongly influenced in recent years by the development of ambitious connectionist models of normal reading. Patterson has been collaborating with McClelland in Pittsburgh and Seidenberg in Montreal to develop such a model, her concern being particularly with the exploration of the extent to which “lesioning” such a model will produce errors that are analogous to those produced by certain types of dyslexic patient. A similar approach is being pursued by Shallice in collaboration with Hinton in Toronto. This work has so far proved extremely promising and will be actively pursued over the coming years. Other aspects of the Unit’s programme in reading research involve (a) relationships between impaired reading and other language skills such as speech segmentation, (b) models for skilled and disordered reading in various orthographies and © plans for more sophisticated neurological localisation of components of the reading process via PET-scanning activation studies.

Learning and Memory (Projects 65-66)

This continues to be an active area, with the Unit involved in research on both working memory and long-term memory. One of the major developments in this area over the last five years has been the attempt to explore the real-world validity of one subsystem of working memory, the Articulatory or Phonological Loop, a system that is concerned with the phonological storage and rehearsal of verbal material. Earlier work was largely confined to laboratory studies, which have left open the question of whether the system is of any practical importance. However, recent studies by Baddeley in collaboration with Vallar and Papagno in Milan, and Wilson in Southampton involving neurological patients with short-term memory deficits suggest that the system is of real importance, both in understanding language, and in learning new phonological sequences, such as new words in one’s native or a foreign language. Further research on normal children by Gathercole and Baddeley indicates that the capacity of this system has a major influence on the initial acquisition of vocabulary and is important for the early stages of reading. Future work aims to continue longitudinal studies to investigate further the ramifications of the system. We also plan to develop a more specific model of the phonological store, as part of the previously mentioned ESPRIT BRA speech project, using parallel distributed processing or connectionist techniques to implement models of memory storage and retrieval in ways that appear to be plausible both psychologically and physiologically.

One of the major features of recent years in long-term memory research has been the growth of interest in autobiographical memory, the capacity to recall incidents of one’s earlier life. This area of memory research has until recently been curiously neglected, probably because of methodological problems in deriving quantitative measures. It is however of considerable practical importance in areas such as eyewitness testimony, and in assessments of the effects of case presentation features on the memory and decisions of juries, both areas that have been studied by Bekerian. Clinical disturbance of autobiographical memory has also evoked considerable interest; this includes work by Shallice and by Baddeley on confabulation in frontal lobe patients mentioned earlier, and research by M. Williams on disturbances in the precision of autobiographical memory in patients who have attempted suicide. The observation of varying patterns of deficit in autobiographical memory in amnesic patients has led to the development of a clinical test of autobiographical memory by Baddeley in collaboration with Wilson in Southampton and Kopelman at Charing Cross. This is part of an ongoing programme concerned with the development of clinical memory tests which has so far produced a test of everyday memory in collaboration with Wilson and Cockburn of Rivermead Rehabilitation Centre in Oxford. We plan to standardise and publish clinical tests of verbal and visual long-term memory, semantic memory and of the various components of working memory.

Connectionist and other network models have also recently had a major impact on theories of learning and memory. Such parallel models appear to capture the characteristics of the processes of storage and retrieval much more naturally than does the more conventional computer analogy, in which information is stored perfectly in a range of discrete memory locations. We believe that the full exploitation of parallel network models for psychology will require a combination of the understanding of their strengths and weaknesses with a willingness to confront them with carefully collected empirical data. The Unit has a strong experimental tradition, and is currently developing its skills in modelling. Houghton is actively exploring connectionist architectures for both long- and short-term learning, while Shanks is concerned with models of concept acquisition and decision. Norris is concentrating on the use of connectionist models in speech perception, a process that almost certainly involves a component of phonological storage. Finally, McLaren, who will be joining the Unit as part of his King’s College Research Centre Fellowship, will be working on a connectionist model of spatial attention, probably in collaboration with Duncan.

Perceptual-motor Skills (Projects 67-68)

In the past Wing has been concerned with developing a theoretical account of noise in the timing of movement. With his theoretical account of timing now widely accepted. Wing is currently evaluating its applicability to new tasks including the coordination of multiple effectors. Recently, in collaboration with Ulrich in Germany, he has started to extend the account of motor variability into the force domain. Time and force are rather elemental aspects of voluntary movement. A more usual focus of attention in research into the control of action is position in space, or, in the case of skills such as writing or drawing, the trajectory of position changes as reflected in the trace left by the pen on paper. Wann and Nimmo-Smith have been investigating strategic constraints on the way such voluntary positioning movements are executed. Mechanical equipment such as a computer pen-plotter is often driven in a very jerky style. This contrasts strongly with the smooth changes in velocity typically observed in human handwriting and which has led people to suggest that movement trajectories are organised to minimise the rate of change of acceleration. APU research has challenged some common simplifying assumptions within this perspective. Reformulated equations of motion are supported by behavioural data but, more importantly, they suggest a way in which the motor system could be informed of the consequences of jerky movement. This therefore constitutes a model of feedback that has implications for the refinement of control in motor development or rehabilitation of neurologically impaired patients. It is expected that this will develop into a useful theoretical basis for current research projects at the APU in motor skills training (even though, regretfully, these will proceed less rapidly with Wann’s lectureship appointment to Edinburgh).

Although variability in output means that our movements are not perfectly accurate, the motor system appears to compensate for errors automatically so that our actions usually achieve a successful outcome. The coordination between opening and positioning of the hand when reaching for an object in the environment is an example that has been studied by Wing in collaboration with Fraser and Turton. If normal use of visual information to guide the hand toward the object is restricted, a compensatory increase in hand opening is observed that improves the chances of encompassing the object. Current research by Haggard seeks to assay the separability of these strategically coordinated elements by imposing additional demands at various phases of reaching. Comparison of the effects of cognitive interference by a secondary task and the effect of mechanical perturbation to movement seem particularly promising.

Thinking (Projects 69-70)

Johnson-Laird, Anderson and Byrne have been further testing the proposal that much thinking involves the setting up and manipulation of mental models. They have systematically compared this approach with an alternative view of thinking based on the operation of sets of logical rules, an approach that dominated the area prior to Johnson-Laird’s theory. The work has been concerned with two criticisms, that the model is too vague to be specified, and that it is not demanded by the empirical evidence. Areas of thinking that have been considered include the comprehension of discourse, everyday informal inferences, and deductions based on prepositional reasoning, relational reasoning and quantification. In each case a formalisation of the proposed mental model has been developed and programmed, and empirical evidence has been collected. The evidence consistently favours the mental model approach and in a number of cases produces data that are very difficult to explain in terms of the rival rule-based hypothesis. This work will continue, but unfortunately not in Cambridge, since Johnson-Laird has accepted a Chair at Princeton University.

Until very recently, studies on animal learning and cognition have proceeded quite independently of equivalent work on human subjects. There are now welcome signs of the two areas beginning to come together, partly under the influence of the development of connectionist learning models, and partly as a result of the development of cognitive theories of conditioning in animals, which appear to have implications for human cognition. Within this latter category. Shanks has been testing models of the judgement of causality, and finding that an associative model based on principles of conditioning offers a better account of the data than one based on normative rules. Similarly, animal conditioning models have proved highly successful in accounting for the results of a categorisation task in which, for example, subjects have to decide on the basis of symptoms whether a hypothetical patient is suffering from one disease or another. The conditioning model has been simulated using a connectionist network; future work will study its capacity to cope with more complex categorisation tasks, including that of diagnosticians making decisions on the basis of actual disease patterns.

Human-Computer Interaction (Projects 71-72)

This is an area in which the Unit has worked for many years, starting at a time when it was virtually unexplored, and reaching a point now at which it is one of the most intensively studied areas of applied psychology. One of the difficulties in working in this area is that the technology changes so rapidly that particular systems become obsolete before they have been adequately studied. This means that much of the applied work in the area has to be based on rule-of-thumb techniques, which ideally should be based on earlier evidence. Since the user of such information is typically not a psychologist, a major problem is how the necessary information can be delivered, and it is this that has concerned both Barnard and Young in recent years. Both have chosen to use AI techniques, with Young and Green opting to develop a cognitive model of the user that allows the software designer to program in the system and task characteristics, while Barnard has developed an expert system in which the rules are based upon Interacting Cognitive Subsystems, his very ambitious model of cognition. Working with these ideas. Young and Barnard are currently collaborating on an ESPRIT Basic Research Action, aimed at bringing modelling techniques from cognitive and computer science closer to the practical needs of software designers.

We remain active in the related area of exploring the cognitive demands of technical communications. Wright has continued her detailed analysis of the representation of linguistic information, exploring the conflict that sometimes occurs between the linguistically graceful and the logically desirable. She continues to provide practical help for those concerned with designing forms, as well as other varieties of communication, for example via the maps and signs that attempt to guide the visitor around a large and complex hospital. Investigation of the problems people have in communicating technical information suggests that they are often insufficiently aware of the alternatives available, whether to use words or pictures, and whether to provide an enquirer with the quickest or the easiest way. The development of desktop publishing offers an increasing range of potential resources for the communicator; if they are to be used effectively, we need a more detailed and sophisticated understanding of the problems facing both the communicator and the recipient of the information.

Transport System Users (Project 73)

Research on the behaviour of transport users has been a prominent feature of the Unit’s work for many years, and continues to be an area of considerable activity. A previous project involving Brown, Duncan, Groeger and P. Williams, concerned with comparisons amongst novice drivers, normal experienced drivers and experts revealed, among other things, that the normal experienced drivers were poorer than either of the other two groups on certain components of driving such as mirror-checking. The tasks concerned seemed to have the characteristic that failure to perform them does not normally lead to immediate feedback, although in the long run failure can be extremely serious. This has clear implications for road safety.

Detailed analysis of the skill of driving suggests that it comprises many different and independent subskills, making prediction of success in trainees very difficult. Executive functions appear to be less important than might have seemed likely, a conclusion that is consistent with a small study of head-injured patients. This showed that even patients with clear evidence of executive dysfunction show little impairment in driving skills, and suggests that medical criteria for return to driving should be re-examined.

A series of new externally-funded projects involving Groeger, Brown, Chapman and Grande has just begun. One collaboration (with Paris and University College London) concerns estimating time to coincidence or collision. It attempts to model the decisions drivers make at junctions. This should provide assistance to traffic engineers devising countermeasures to the problems of risk-taking at junctions. A second related study is concerned more directly with perception of risk, using video tapes of specific situations, and requiring drivers to assess the danger and relate it to their driving behaviour (this is funded by a contract from General Accident PLC).

A third project, this time funded by the CEC DRIVE Research Initiative, is concerned with the role of feedback from driving instructors during the process of learning to drive. It will attempt to relate this to the type of accidents encountered subsequently, using this information to identify the type of instructional support that might be given to the learner by an “intelligent” vehicle. This project is carried out in collaboration with the Traffic Research Centre at Croningen. Brown is due to retire in three years’ time, and the future of this area is one that is of considerable concern. We would hope to continue to work in this area, provided we can recruit senior staff who are capable of blending the many practical problems this area offers with the prospect of genuine theoretical development.

Vision (Projects 74-76)

A major component of the Unit’s work in this area was the development by Watt of a theory of human vision and visual attention that combines information from psychophysics, computer science and cognitive psychology and is expressed in a recent book [561]. Unfortunately, Watt has just left to take up a Personal Chair in Psychology and Computer Science at Stirling. We hope to replace him by a senior appointment in a similar area.

Meanwhile, Wilkins’ work on visual discomfort and environmental design continues to be extremely productive. He has shown that the characteristic flicker and stripe patterns that trigger epileptic attacks in photosensitive patients are also a major source of complaints of eyestrain and headache in non-epileptic subjects. This has important practical implications for a wide range of environmental design issues, including fluorescent lighting, computer VDUs and even the design of typeface, where certain types can be shown to produce clear stripe effects, and accompanying complaints of eyestrain and headache. The potential environmental significance of this phenomenon is very substantial. At the same time, Wilkins and Neary have been exploring possible mechanisms, elaborating and testing a theory of eyestrain described in the last progress report.

In the meantime, Wilkins has been applying the visual techniques developed to provide clinical tests useful in the diagnosis of a range of diseases including multiple sclerosis, optic neuritis, diabetes and glaucoma. Future proposals involve the continued investigation of visual discomfort in the office environment, and ways in which it can be alleviated, together with a continuation of the investigation and modelling of the visual symptoms associated with headache and reading.

Psychophysiology (Projects 77-78)

Work by Wilkinson on sleep has involved continued analysis of data collected from earlier fieldwork on individual sleep disturbance, together with the development of measures of sleep on/offset, using both behavioural and physiological measures. Future work will develop portable sleep detectors for use in industrial and field situations. Wilkinson is due to retire in a year’s time, an event that colleagues in North America and Britain plan to mark by organising a meeting in Cambridge on sleep and performance. Levey, who forms the second senior member of the psychophysiology section, is also due to retire, bringing to an end his very productive line of research on human classical conditioning, carried out in collaboration with Martin at the Institute of Psychiatry. Plans for the future of the psychophysiology section will be discussed below.

Emotion and Cognition (Projects 79-80)

The Unit has sought to develop links between experimental and clinical psychology in the belief that any adequate theory of cognition must be able to incorporate an understanding of the role of motives and emotions. Since it is difficult to manipulate emotions ethically within the laboratory, we felt that work on clinical patients could be potentially of great significance for understanding normal cognition. At our last progress report, we had established a group in this area, but the Board felt that it was still too soon to assess the success of our attempt to bridge the gap between clinical and cognitive psychology. We are now in a much stronger position, with an active and coherent group that is not only developing strong connections between these two areas of psychology but is also beginning to influence theory within each of them. One indication of the extent to which research on cognition and emotion has become integrated into the work of the Unit is the fact that no fewer than eight cognitive psychologists who do not see emotion as their principal area of research, have been involved in research in cognition and emotion over the period since our last progress report. These include Baddeley, Barnard, Bekerian, Conway, Dritschel, Johnson-Laird, Levey and Wilkins. A second achievement of the group has been the publication by Williams and Watts in collaboration with Mathews and MacLeod (of St George’s Hospital Medical School) of Cognitive Psychology and Emotional Disorders, a book that has been very favourably reviewed, and which we believe reflects the growing tendency for cognitive psychology and clinical psychology to interact fruitfully. The work in this area falls into two sub-areas, the interaction of emotion and cognition (Project 79), and the analysis and treatment of emotional disorders (Project 80). Past work on cognition and emotion has included the communicative theory of emotions devised jointly by Johnson-Laird and Oatley of Glasgow. Bekerian and Conway have explored the structuring of emotional and conceptual knowledge in a way that links up with previously-described research on semantic and autobiographical memory, and with the work by Williams on autobiographical memory in attempted suicide patients.

Teasdale has been concerned with the role of mood congruent memory in maintaining negative mood states, and has gone on to study methods of controlling the flow of negative thoughts, which have been shown to help maintain the depressed mood state in patients. A series of experiments have used Baddeley’s working memory model to explore methods of controlling such thoughts, demonstrating the importance of the Central Executive component rather than peripheral slave systems in the process. Future plans involve adapting Barnard’s model of Interacting Cognitive Subsystems to explore further the control of negative thoughts, with a view to developing therapeutic methods for encouraging and maintaining more positive affect in such patients. Barnard plans to devote more time to this and rather less to human-computer interaction throughout the coming five years.

Work on the analysis and treatment of emotional disorders has concentrated on patients suffering from depression, and from phobias. Work by Watts on depression has demonstrated genuine memory deficits which are not simply due to subjects having a bias against responding freely, and has suggested that the problem occurs at least partly as a result of the reduced organisational activity indulged in by the subject. Depressed patients tend, for example, to fail to pick out the more’ important features of text, and are more likely to rely on simple rote rehearsal. On the other hand, use of imagery is unimpaired, and Watts has successfully applied these findings to the treatment of work problems in students. This particular line of research is regarded as complete. Attempted suicide presents a major practical problem which at present has not yielded readily to treatment. Williams has investigated the autobiographical memory of patients in an attempt to elucidate the nature of the hopelessness that appears to be an important determinant of whether or not the patient will attempt suicide again. Williams’ work suggests that although such patients can access autobiographical memories, they report memories that are excessively general, and appear to have great difficulty in producing detailed specific recollections. Subsequent work showed that a similar phenomenon occurs in other depressed patients, and furthermore indicated that the phenomenon is also present in ex-patients who have recovered from their suicidal crisis. He proposes to examine this phenomenon in more detail, in particular exploring the relationship between autobiographical memory, hopelessness and the control of action, exploring the extent to which autobiographical memories of the past can be related to the patient’s prediction of what will happen in the future. In collaboration with Scott and Ferrier at Newcastle, Williams will be studying a group of depressed patients longitudinally, with a particular view to exploring whether the generic style of recall identified in depressives will predict dysfunctional attitudes and subsequent relapse. A series of experiments on patients’ memory for phobic objects (such as spiders) by Watts and collaborators has shown a pattern of results with some similarities to the lack of specificity in autobiographical recall by depressives. Phobics tend to have both very poor recognition memory and rather undifferentiated cognitive representations of phobic stimuli. This lack of precision appears to be associated with poorer subsequent emotional habituation to the stimuli. It is as if, in both the autobiographical memories of suicide patients, and the perception of fear-inducing stimuli by phobics, the degree of associated anxiety can be reduced by avoiding detailed processing and hence “distancing” the stimulus. Unfortunately however, this distancing mechanism appears to make it harder for the patient subsequently to adapt and come to terms with the source of anxiety. This emphasis on impoverished stimulus processing differentiates Watts’ approach from that of Lang who emphasises the importance of the response aspects of anxiety. Future work will explore this hypothesis further, attempting to improve phobic encoding by inducing positive mood, and by attentional instructions. If successful, this should not only improve subsequent recall, but also lead to better desensitization. A related problem is that of dealing with emotional memories which may continue to cause acute distress in patients long after the occurrence of the event. Recent work suggests that these memories again tend to be preoccupied with the patient’s emotional response, with little attention to the details of what occurred. It is suggested that this prevents effective emotional processing, and that better ways of working through emotional memories may be available. The work is closely related to that of Williams on generic autobiographical memory, and of Teasdale on intrusive thoughts and mood biasing.

Finally, a collaboration between Watts and Levey is investigating a cognitive treatment of sleep dissatisfaction. This work is conceptualised in a working memory framework, and uses articulatory suppression as a means of blocking verbal behaviour, while requiring suppression to occur at irregular intervals, a task that occupies but does not stimulate and overload the Central Executive component. Preliminary results appear to be encouraging, and a formal trial of the treatment is just beginning.

The Next Five Years

While we have attempted in the body of the Progress Report to indicate for each research area, the direction we plan to take, given the number of projects, it may be difficult for the reader to gain an overall feel for the broad research strategy of the Unit. The present section aims to fulfil that function.

In many ways the broad theme of the Unit’s work has remained remarkably constant over its 45 years of life. We began with a strong commitment to theory, based on the concept developed by Craik of the model as a means of theorising, and using the electronic computer to model human cognition. We are still strongly committed to theory, still use an information-processing metaphor, and tend to rely quite heavily on computer modelling. In our last Progress Report we made a plea for better equipment, and I am delighted to say that the Council responded very positively. Much of the Unit’s theoretical work continues to be concerned with the detailed modelling of specific cognitive processes. However, the development of the techniques of Artificial Intelligence has led to the creating of unified theories of cognitive processing. Within the Unit three broad approaches to achieving such integration are represented.

One approach is based on connectionist architectures (Parallel Distributed Processes). Such models emphasise the interaction among large numbers of inter-connected subunits. Another approach to parallel processing has been achieved by an architecture comprising a number of dedicated processing modules. In this approach, which is typified by the Interacting Cognitive Subsystems model, structural complexity is traded against processing simplicity. This work provides a link with the third approach which is based on models using a Production Systems architecture, with cognition being modelled as the operation of rules that have been learned. The next five years will see clarification of the scope and power of these theoretical approaches. My own view is that the viability of these theories depends upon the level of the cognitive functions being modelled, with some tasks such as pattern recognition being much more readily captured by connectionist models, while other tasks such as planning and problem solving may be more amenable to a Production System approach. It is likely that any powerful account of complex human behaviour will require an integration of these different approaches and the Unit is relatively unusual in having groups active in all these areas, concerned with a diversity of cognitive functions and with a strong commitment to linking these approaches to empirical data.

A second feature of the Unit’s work from its inception has been a concern with applying psychological knowledge to the solution of real world problems. Rarely does psychological theory lend itself to simplistic application, and the solutions that the Unit has been able to provide takes many forms. In some areas (e.g. audition and speech) it is possible to deliver products which solve or contribute to the solution of practical problems. In other areas (e.g. driving and interacting with computers), the diversity of potential solutions means that ways have to be found for helping non-psychologists to understand the cognitive implications of the options they are considering. The Unit is starting to explore ways to bridge this communication gap, including the use of expert systems and simulations of cognitive functioning that designers can run in the task environments under consideration. Over the next five years we will assess the utility and-power of these approaches to ‘giving psychology away’. Moreover we expect the classes of communication being developed to have relevance to other problem domains where the application of psychological knowledge is far from simple or obvious (e.g. rehabilitation).

The Unit in its early days had a relatively strong biological emphasis, provoked in part by the military problems of the Second World War which generated an interest in environmental stressors such as heat and noise, as well as in factors such as fatigue and combat neurosis. During the 1970s, this aspect of the work of the Unit tended to become less prominent, but revived again with the advent of the group studying the relationship between emotion and cognition in normal and emotionally disturbed subjects. I would see the development of research on cognition and emotion involving three phases. The first of these has been concerned with establishing that cognitive psychology does have a role to play in this area. I believe that we have already begun to show that the techniques and concepts of cognitive psychology can throw light on clinical problems, which in turn enrich the cognitive theory. The second stage is one of ‘developing and testing theoretical models that incorporate both emotional and cognitive factors. This has already begun and is reflected in the many collaborations that have developed between the group whose primary concern is with emotion and cognition, and a range of colleagues in more mainstream cognitive psychology. I would see the third stage as involving the development and testing of methods of treatment. This has already started in the case of the proposed treatment for insomnia by Watts and Levey. However, in general it is realistic to expect the development and application of work in this area to be gradual, with theoretical insights leading first of all to experimental treatments, leading over a period of years to the development of standardised treatment packages and finally to their evaluation by multi-centre trial. A second area in which the clinical and biological emphasis has steadily increased, is of course that of neuropsychology, an area in which the Unit has had, and continues to have considerable strength. Much of the theoretical progress in this area has come from applying cognitive models to single cases, often selected as having a very pure functional deficit. I believe that we are now developing our technical and conceptual skills to a point at which we are able to tackle patients with more than one deficit. This is an important development for two reasons, first because it increases the number of patients that can profitably be studied, and secondly because it means that we are in a much better position to tackle the complex cognitive deficits that accompany neurological diseases such as Alzheimer’s Disease, Parkinson’s Disease, and schizophrenia. This leads to a natural alliance between the cognitive psychologist, the clinician and the neuroscientist. This aspect of our work is likely to be further stimulated if the proposed Interdisciplinary Research Centre goes ahead. Even if it does not, the contacts made in discussing IRC proposals themselves seem likely to stimulate collaboration with our neurobiological and clinical colleagues in this area. The major change that we are proposing over the next five years is of course the replacement of the Psychophysiology Section with a group concerned with rehabilitation. The problem of rehabilitating the brain-damaged patient is of course one of enormous practical and social importance, and one that has in the past been sadly neglected. We believe that developments in neuropsychology have now reached a point at which it can start to tackle these issues with some hope of success, and that the APU with its tradition of blending pure and applied research is in an ideal position to collaborate with the rapidly developing Cambridge Medical School in developing a centre of genuine excellence in this area. It will require the goodwill and collaboration of the regional administration, of the University Medical School, of our clinical rehabilitation colleagues, and of course the strong support of the Board. We have already begun local discussions and made initial contact with the Department of Health, and so far there appears to be considerable general enthusiasm for the proposal.

The proposed development will involve a substantial expansion of the clinical service at Addenbrooke’s, with our own involvement being an integral part of such a newly-developed Rehabilitation Centre. Realistically, it will probably be four or five years before such a centre is up and running. Bearing that in mind, I would hope to see a gradual build-up of the Unit’s rehabilitation commitment, initially relying on sub-optimal accommodation, but comprising by the end of the five-year period a team of some eight or ten scientists (see Section F). I would hope that by the time of our next progress report we would already be starting to demonstrate the fruitfulness of such an approach, while accepting that making real progress in this important but challenging area is likely to take substantially longer than five years. It is for that reason that an MRC Unit, with its remit for engaging in long-term research programmes is particularly well-placed for developing such an enterprise.

The progress report for 85-89 covered work published in some 753 papers, reports and theses.

Director’s Overview: Progress Report for the period 1990-1994

This Progress Report coincides not only with my own retirement from the Directorship after 20 years, but also with the Unit’s 50th anniversary. I hope I can therefore be forgiven for taking this opportunity to look at the Unit’s remit from a rather broader perspective than would normally be justified. Throughout its first 50 years, the Unit has consistently operated at the interface between psychological theory and practical questions, basing general models of human cognition on specific empirical evidence, from both naturalistic and laboratory-based studies, and using this evidence in the attempt to solve applied problems. The Unit’s first Director, Kenneth Craik, was perhaps the first person to formulate clearly, and test empirically the idea of the computer as a model of complex human behaviour. He was tragically killed in a cycling accident one year after becoming Director, and was succeeded by Sir Frederick Bartlett who was also Professor of Psychology. Bartlett had a great talent for combining careful experimentation with the development of theory that was applicable to naturalistic as well as experimental data. As such he was a precursor of the subsequent so-called cognitive revolution of the 1960s, and his reputation has continued to be high both in Europe and North America. When he retired he was succeeded by Norman Mackworth, probably the least theoretically-oriented of the Unit’s directors, but whose influence on the Unit continues to be strong, through the non-hierarchical management style he favoured, and not least because of his purchase of No. 15 Chaucer Road, the Unit’s home since 1951.

When Mackworth later emigrated to Canada, he was succeeded in 1958 by Donald Broadbent, who shortly afterwards published Perception and Communication, a book that provided the first coherent theoretical account of cognition in terms of the information-processing metaphor previously developed by Craik. It was the forerunner of the revolution whereby cognitive psychology gradually became the dominant theoretical paradigm within psychology. While not supplanting other approaches, cognitive psychology has provided an information processing theoretical framework that allows integration across a wide range of areas, coupled with the potential for developing precise models in more closely specified areas. Broadbent’s own work over the succeeding years illustrated this, as does the following Progress Report which represents a blend of approaches reflecting influences as diverse as neurophysiology, animal learning theory, clinical psychology and computer science. During Broadbent’s 16 years as Director, he developed and consolidated the Unit’s position as an international centre for research in pure and applied cognitive psychology. During my own period as Director I have tried to continue this tradition. This has involved maintaining core strength in the major areas of cognitive psychology, and at the same time seeking areas of application that are tractable and fundable. Most importantly, such areas should be capable of feeding back results that will challenge and enrich the underlying theory. Psychology has been fortunate over the life of the APU in that it has always been possible to find such areas of application, although it has been necessary to change direction periodically in order to take full advantage of new opportunities.

The Unit was founded in 1944 on the basis of research projects stimulated by the Second World War, and for many years its work continued to be closely related to such military problems as pilot fatigue and the effect of environmental stress. Defence-related research was later largely replaced by problems stimulated by other Government departments such as the Post Office and Ministry of Transport. With the increasing importance of computers, a larger part of our work began to be carried out in association with industry, though sadly we have usually found it easier to establish research links with US, rather than British-based companies. In the present economic climate, however, even North American companies are rarely able to fund anything other than short-term research.

Fortunately, it has in recent years been increasingly clear that health-related problems present an ideal opportunity for applying and enriching cognitive psychology. Our initial ventures were into neuropsychology, where the careful study of single cases with relatively pure cognitive deficits caused by brain injury proved to be extremely fruitful. The field has developed to a point at which our concepts are now able to deal with a much wider range of cases whose cognitive deficits are less specific, and this in turn is stimulating the development of the new and related field of cognitive neuropsychiatry, whereby cognitive psychology is applied to the analysis and understanding of psychiatric disease.

Some 10 years ago, we decided to try to extend the range of cognitive psychology to include studies of the interaction of cognition and emotion, and were able to attract Watts from a senior clinical post at Kings College London. He was later joined by Teasdale from Oxford, and Williams from Newcastle, and in collaboration with Mathews and Macleod from St George’s they succeeded in developing an approach that applied the concepts and techniques of cognitive psychology to the study of emotion and its disorders. This is now part of a vigorous area of overlap between cognitive psychology and the problems of clinical practice.

Our most recent attempt to blend cognitive psychology and practical problems is reflected in the neuropsychological rehabilitation group. While the group has not yet reached full size, or indeed gained access to its clinically-based accommodation, I am delighted with the progress that it has made in demonstrating the viability of neuro-rehabilitation as a fruitful applied area of the application of cognitive psychology. One crucial advantage of our development of neurorehabilitation as a research area is the extent to which it is benefiting from the rapid development of clinical neurosciences in Cambridge. I expect us to continue to benefit from our growing collaborative links, in particular taking advantage of planned expansion of neuroimaging in Cambridge, and of the establishment of the IRC in Brain Repair. At present, the work of the IRC is principally concerned with animal models, but once the feasibility of clinical trials develops, then I would anticipate close collaboration. It is clear that many of my colleagues see considerable potential for collaboration between cognitive psychology and the neurosciences. I hope my successor will be as enthusiastic about that prospect as I am. At the same time, I trust that he or she will bear in mind that the Unit’s success has come from its capacity to maintain considerable strength in the core areas of cognitive psychology, providing a solid scientific base that is capable of capitalising on whatever area of application is currently most productive, while allowing sufficient flexibility to seek other applications when the time is ripe. Although the Unit’s general remit has remained much the same, the form and content of its scientific contribution has evolved under each of its successive directors. Looking back over the period since 1974, I would like to think that research by APU staff has not only kept up with the best national and international work in both pure and applied cognition but also has continued to help shape the core agenda for our principal fields of operation.

In the mid seventies, the domains of coverage for theory and experimentation were largely those of traditional information processing psychology. Fractionation of component operation in simple pure and applied tasks was the dominant mode of scientific enquiry guided by locally constrained mathematical models, “box” models or verbally formulated theory. In the mid nineties, fractionation plays a key role but is now embedded in a much more interdisciplinary outlook. Our typical tasks now range from simple to complex; our theories tend to be more integrative; our empirical methods are of far greater relevance to charting performance in clinical as well as normal settings. A substantial proportion of our modelling effort is now routinely implemented, for example, mathematical models of auditory image creation, connectionist models of language or memory systems, or symbolic representations of mental models or of complex task performance. Not only the form of the theory has developed; its content now extends outwards to form interdisciplinary links with the basic cognitive sciences of linguistics, artificial intelligence and computer sciences through to clinical disciplines and neurosciences. In each of these areas it can be argued that researchers at APU have played their part – reference to core research summaries and teaching texts testifies to this. I hope that the tools, techniques and theories now in place will form a substantial and relevant foundation for future advance in all of these areas. What follows in this introduction is my overview of the major advances during the last five years of work at the APU, and also of plans for future work, organised into six scientific programmes. Creating an environment for these advances has been a stimulating and thoroughly enjoyable challenge, made possible by the MRC Unit system. Long may it flourish!

Programme 1: Perception and Action

The purpose of this programme is to develop models of perception at a level between sensory physiology and cognition – models that enable us to make quantitative predictions about perception and behaviour in circumstances where they are predominantly governed by the external stimulus. The research falls into three broad areas, one concerned with audition, a second with vision, and a third with the control of movement. All three areas are well established at the Unit, and in the last five years we have been able to capitalise on theoretical advances to produce patents which have been developed commercially.

Roy Patterson’s Auditory Image Model, described in our last Progress Report, has been substantially developed over the period, with much of the work being achieved through collaborations with European colleagues through an ESPRIT contract, and subsequently with North American and Japanese groups. Considerable software development has led to a user-friendly version of the model that was made generally available on Internet, resulting in transfer to 125 sites within the past eight months. The model has proved to be an effective “front end” for speech perception and performs somewhat better than the leading FFT preprocessor for both phoneme recognition and speaker identification, despite the fact that the full capacity of the model was not realised in these initial tests.

Theoretical exploration of the model has been primarily concerned with explaining the perception of sound quality or timbre. Traditionally, auditory models predict our perceptions from the power spectrum of the stimulus. Patterson’s model differs in assuming asymmetry in the auditory filter system, which predicts that ramped tones, in which the sound pressure increases gradually and terminates suddenly, will give rise to a very different auditory image from damped tones which have the reverse temporal pattern, despite the fact that ramped and damped sounds have identical power spectra. As Patterson’s model predicts, marked perceptual differences occur, whether the sound sequences are based on pure tones or noise.

One of the earliest practical products of Patterson’s psychoacoustic research was a system for designing auditory warnings that are maximally audible without being startling, highly discriminable, and easy to learn. Warnings designed on these principles are currently used in North Sea helicopters and were used in RAF helicopters in the Gulf War. Subsequent work has developed warnings for civil aircraft and fixed-wing military planes, and the same principles have been applied to developing trackside warnings for British Rail workers and an international standard for warnings in hospital operating theatres and intensive care units.

Future work will continue the development of the auditory image model with a more user-friendly interface and a simulation of the physiological characteristics of the cochlea that should extend its application to the analysis of hearing disorders (in collaboration with colleagues in the Cambridge Psychology Department). In a collaboration with Armstrong Laboratories in the U.S.A. the model will be implemented on an analog VLSI chip as part of an international programme to develop a “silicon cochlea”. Utilisation of the model as part of an automatic speech processor will continue in collaboration with Armstrong Laboratories and with ATR in Kyoto. Future theoretical work will concentrate on two synthetic sounds which produce complex tone and noise perceptions that traditional auditory models fail to explain. The stimuli are matched pairs of damped and ramped sounds, and iterated rippled noise. The perceptions are interpreted in terms of the time-interval patterns the sounds produce in the auditory image. Finally, we will continue to provide expertise in the development of auditory warnings, as and when appropriate.

The psychoacoustics programme has recently been further strengthened by the appointment of Carlyon, who was 1994 recipient of the Acoustical Society of America’s Bruce Lindsay Award. He will be studying the physical factors that allow a listener in a noisy room to pick out a single sound source from the complex and intermingled signals at the ear.

In the area of vision, Wilkins has extended his earlier work on photosensitive epilepsy to a wider population, resulting in a general theory of visual stress and discomfort. He has shown that certain frequencies of stripe or flicker are particularly likely to lead to visual distortions, reading problems and headaches in non-epileptic subjects, a response he attributes to the hyperexcitability of neurons in the visual cortex. The theory has relevance for lighting, text design and the development of visual display units.

Recent work has concentrated on the observation that ophthalmically-tinted spectacles can reduce symptoms in susceptible individuals. The optimal tint varies from one subject to another, and so Wilkins has developed an instrument (the Intuitive Colorimeter) that facilitates measurement of the appropriate tine. This has been validated, and is now commercially available. It is being used increasingly widely and it appears to be particularly helpful for certain children with reading difficulties. A simplified assessment procedure using transparent overlays has been devised for screening purposes, and will be further developed over the next few years. Future plans involve collecting more evidence on the capacity of the model to deal with migraine headaches, and will investigate the therapeutic value of using ophthalmically-tinted lenses. Other applied issues include the study of photophobia in recently head injured patients.

At a more theoretical level, the processes underlying visual discomfort will be further explored using psychophysiological measures including pupil size, eye movements and cortical evoked responses. The optimal method of testing the hyperexcitability theory however, is through PET scanning or functional MRI, both of which should be available locally in the near future.

Wing and colleagues have continued to study the timing and control of movement. His widely used two-level model for repetitive movement has been elaborated into a multi-level, hierarchical model for rhythm. This has been shown to be applicable to situations in which the control of timing is explicit, but not to the timing of patterned responding in tasks such as typing and handwriting in which the rhythm emerges from the task, rather than being explicitly imposed. Yet a third variant on timing occurs when a number of individuals attempt to synchronise their responding, as in a rowing eight, where the externalisation of potential cues for coordinating individual timing provides valuable hints as to the underlying mechanisms. Research into the variability of timing has been complemented by analyses of force variability. This has developed into a concern with temporal coordination between grip force used to hold an object and forces created in moving the object in the environment. Subtle adjustments in grip force have been demonstrated that anticipate changes in forces acting on the object being gripped. Similar finely tuned relations between natural reaching and hand-shaping also cast light on the subtle link between perceptual factors and the anticipatory control of action. The breakdown of such processes following stroke, cerebellar disease or in utilising an artificial hand, illuminate the underlying mechanisms, and have substantial implications for therapy. Balance during standing presents another example of the interplay of perception and action. Anticipatory and reactive components of balance have been studied using a recently patented device that provides a simple measure of the subject’s weight distribution. Together with a newly developed method for disturbing balance by applying a gentle force to the pelvis, this approach will yield useful tools for analysing and helping remediate balance experienced in neuromuscular disorder. Perception and timing are both crucial to interception tasks such as hitting or catching a ball, or braking to avoid a car collision. While an influential model exists that accounts for these phenomena in terms of a servo system based on a single optical parameter, Tresilian has demonstrated that other models are also consistent with existing data, and has begun to explore both the theoretical advantages and drawbacks of the various models, and to test them empirically.

Future work on control of force and timing of movement will consider the interesting case of bimanual movement, using procedures that load either common, central or lateralised peripheral components of bilateral movements. This work will be complemented by analyses of ensemble timing as it occurs, for example, in rowing. An important aspect of both approaches will be the development of methods for separating long- and short-term fluctuations in movement measures and the evaluation of the roles of local and global information in maintaining coordination of force and time parameters through an extended sequence of coordinated movement. When subjects make movements, such as raising an arm, that disturb balance, automatic postural adjustments occur. These appear to have important parallels with anticipatory grip force adjustments. The possibility of a common, underlying neural mechanism will be studied via correlations across a range of experimental conditions in normal subjects, and also via evidence of associated deficits in patients with Parkinson’s disease, and patients suffering from cerebellar damage. Standing balance will be investigated in stroke patients with a training study that will include conditions designed to improve anticipatory weight adjustment associated with initiation of walking. This work will be complemented by a study of stroke patients who spontaneously develop a maladaptive response to instability and are particularly prone to falling. Finally, research on balance will continue with further analysis of evidence suggesting that certain concurrent mental tasks may interfere with balance, particularly in elderly subjects.

Programme 2: Attention and Cognitive Control

Attention refers to the process whereby an organism controls the flow of information through its nervous system, selecting and coordinating certain stimuli and actions, and inhibiting others. It has continued to form a major component of the Unit’s research programme since Broadbent’s classic work in the 1950s rescued the concept of attention from decades of neglect. It typifies the Unit’s approach to science in drawing on a very wide range of tasks, from the selection of simple stimuli to abilities as complicated as learning a new word-processing programme, and it attempts to tackle the underlying problems using methods with a wide range of analytic levels, from single unit recording in monkeys to the construction of general models of cognitive processing based on techniques of artificial intelligence. We believe that an adequate theory of attention will require a conceptual understanding at all of these levels. For purposes of exposition, the work can be split into two major groups; one of these is concerned principally with attention as a means of selecting one component of a complex perceptual array. This line of work tends to use comparatively simple tasks, and is already demonstrating the value of combining cognitive psychology with more neurobiological approaches. The second group of studies is concerned with the selection and coordination of action, and has stronger links with the field of cognitive science, with clear implications for the practical problem of understanding people interacting with complex technological systems. It seems likely that both domains rely on broadly similar underlying mechanisms, in which control is exercised by the inhibition or excitation of neural systems; but it is likely that the underlying neural systems involved will prove to differ.

Duncan contributes to both aspects of attention research, with his integrated competition model of visual attention being a good example of the fruitful interaction of cognitive psychology with neurobiology and neuropsychology. Recent work supports the view that visual attention arises through cooperative activation in multiple brain systems, which converge to work on the same visual object. The process develops over several hundred milliseconds, as revealed by extended interference between one object and another. Work with Desimone at NIH has used single unit recording techniques in monkeys to study the neurobiological basis of selective attention. When the animal is required to look for a particular object, neurons in the inferotemporal cortex that are associated with perceiving that object appear to be primed, while those associated with non-targets are suppressed. Work using both lesion and PET scanning methods in human subjects provides further evidence for attention as a process involving integrated competition within multiple brain systems. The process of inhibition in visual attention has been simulated by Houghton using a connectionist computational model that is proving influential in the area of memory as well as attention. In experimental work, Lavie has begun to investigate limits over the voluntary control of visual processing. Complaints of attentional difficulties occur widely in patients suffering from stroke or head injury, and this has led to active collaboration between cognitive psychologists such as Duncan and Lavie, whose primary concern is with the understanding of normal attention, and neuropsychologists from the rehabilitation group. Goodrich has been studying the phenomenon of extinction, whereby a patient may be able to detect a single stimulus in the visual field contralateral to a lesion, but will fail to do so when a second stimulus is present in the ipsilesional field. The tendency to neglect aspects of personal space is one of considerable theoretical activity both within the Unit and more widely, with theoretical developments beginning to generate promising new methods of treatment, some of which will be described in the rehabilitation section. Preliminary studies indicate that visuospatial neglect may be reduced by input from other modalities, and exacerbated when overall cognitive load is high. We propose to develop and teach coping strategies based on these findings.

Duncan and colleagues hope to increase the extent of interdisciplinary collaboration, combining models and techniques from cognitive psychology with a range of psychophysiological measures, including PET scanning and fMRI measures. The work with Desimone will continue, using single unit recording to investigate the neurophysiological and anatomical basis of attention. Questions to be addressed include the nature of competition both within and between visual systems, and the separability of visual and spatial aspects of attention. A panel of patients with clearly specified lesions is currently being formed, and comparisons will be made between patients with parietal, occipitotemporal and frontal lesions to test hypotheses about the various processes underlying selective attention.

While attention has been regarded as a legitimate topic of investigation within psychology for at least 30 years, the related issue of the nature of consciousness has, until recently, been treated with more scepticism. However, evidence from the laboratory and the neuropsychological clinic from such phenomena as blindsight (the capacity of some cortically blind patients to process visual information in the absence of visual awareness) and implicit learning in amnesia have forced cognitive psychologists to come to terms with the need to develop theories of conscious awareness. Marcel, whose earlier empirical work contributed to the acceptance of consciousness as an important topic within cognitive psychology, has been devoting a good deal of his time to both theoretical and empirical work concerned with the question of whether consciousness should be regarded as unitary. Marcel takes several different lines of his work to suggest a division between phenomenal experience and higher-order reflexive consciousness. This second aspect of consciousness is closely linked to focal attention and self-monitoring, and plays a role in what we can report and what gets consciously remembered. The lack of access between these levels of consciousness can be seen as underlying research on anosognosia, where a person is unaware of a neurologically acquired deficit. Work with Tegnèr in Stockholm has shown that patients with anosognosia are not simply confused, but that their degree of awareness of their deficit may depend crucially on the way in which the relevant information is probed. A related aspect of conscious awareness is that involved in reporting bodily sensations, a capacity that is very important in medical diagnosis, but little studied. Future work will further investigate the capacity of subjects to localise pain, and will further develop Marcel and Tegnèr’s anosognosia scale as a general clinical instrument. The breakdown in monitoring mechanisms found so strikingly in cases of anosognosia has clear parallels to the need to monitor our own abilities in everyday life. Self-monitoring played an important role in a recent attempt to minimise anaesthetic accidents by encouraging anaesthetists to participate in an anonymous incident-reporting system. Sellen has begun to investigate some 3,000 such reported incidents, developing a categorisation system as part of an attempt to understand the errors and reduce them. The most frequent incidents appear to be simple slips (“the wrong drug problem”) associated with haste and distraction. The analysis is continuing and a more detailed observational study is being carried out in association with Papworth Hospital.

Understanding such slips of action requires a theoretical framework that is capable of dealing with attentional control as part of the coordination of action needed to perform complex tasks. Duncan’s work in this area stemmed from a study of driving behaviour, but has in recent years concentrated on conceptualising and studying the way in which actions are controlled and scheduled. Again he has used a range of approaches, from the study of goal neglect in laboratory tasks, through studies on patients with frontal lobe lesions, to individual differences in general intelligence. Evidence from PET studies, from lesion studies and from the laboratory all indicate the importance of frontal lobe systems in setting and monitoring goals, and in the processes underlying differences between individuals in general intelligence. Future research will extend the work on patients with clearly specified lesions, and will utilise dual task methodology to develop a more precise understanding of the nature of executive control. It is planned to combine carefully selected tasks with PET scanning, in order to investigate whether executively demanding tasks place demands on specific areas of the frontal lobes, to what extent they limit performance by common demands on content-specific areas, and to what extent a demanding task is simply one that requires many different functional areas.

The nature of executive control is a particularly important issue in attempting to understand how people perform complex tasks such as those involved in human-computer interaction. This area has been extremely active in recent years, with Barnard playing a particularly central role in ESPRIT programmes, and Richard Young being heavily involved in both the Alvey and Joint Councils Initiative in Human-Computer Interaction. These programmes have brought opportunities, but also incurred substantial logistic costs, from the need to coordinate large international teams, and to operate with other disciplines and with colleagues in industry. At a practical level the programmes have concentrated on the analysis of complex technological tasks such as understanding the utilisation of a new word-processing programme, or analysing the way in which experienced or naïve users might interact with a new computer system. The aim is typically to provide ways in which software designers can be made aware of the limitations of the user, so as to design systems that are user-friendly. Both Barnard and Young have tackled this task by developing high-level models of the way in which people cope with complex tasks.

Barnard has developed a model, Interacting Cognitive Subsystems (ICS), that conceptualises the user in a way that was originally developed for understanding language use, but has subsequently been substantially extended. (See also section on Cognition and Emotion). Within the attention and cognitive control programme the basic extensions have focused on the interpretation of visual scenes. In one of the more practical studies making use of such theoretical extensions, the ICS system was taught to human factors students, who proved to be able to use it effectively, given the appropriate task-description vocabulary. They did not need to understand the underlying theory.

Dissemination is clearly an important issue, and the work has been widely presented and is beginning to appear in text books for software designers. Much of the work in this area is disseminated electronically through Internet, a process that allows dissemination to be monitored. Hence we know that in the last five months there were 1,160 requests for documents from this project. Most (740) were from the various collaborators, but there were some 420 requests from unrelated investigators from a total of 18 different countries. It is becoming clear that this will be an increasingly important method of scientific dissemination, particularly for items such as computational models which are not readily communicated within the current journal system.

Over the next five years, Barnard will be devoting a rather larger amount of his time to applying his model to the study of cognition and emotion, but will continue to operate within the general area of executive control, making the model available in tutorial form, and collaborating in a venture to specify the theory in more formal terms. Future empirical work will concentrate on the task of searching iconic arrays, and on the way in which information is coordinated across sensory modalities.

Young has also used human-computer interaction as a test-bed for a more general conceptualisation of cognitive function, in this case based on the SOAR architecture developed in the U.S. by Newell. The model has a highly constrained architecture, and uses learning and problem solving procedures to tackle a wide range of cognitive tasks. It has been applied by Young and his colleagues in recent years to study the mistakes made by subjects first encountering a Macintosh computer, and to demonstrate the role of mental models in using simpler devices such as calculators. Work with Logica, a major British information technology company, has been concerned to develop methods of assisting software designers in creating usable systems. Future work will concentrate on using the model to conceptualise the representation of task goals, and to provide a better understanding of the way in which people operate within the visually-based systems that are becoming increasingly dominant within HCI.

At a more theoretical level, Young will be concerned with comparing the way in which different conceptual models within cognitive psychology account for the same phenomena. For example, although the concept of working memory plays an important role in SOAR, different assumptions about working memory are made by SOAR, by Barnard’s ICS, and by Baddeley and Hitch’s working memory model. It would be valuable to know which of these differences are largely notational, and which reflect incompatible but testable basic assumptions.

The final component of this section concerns the Unit’s work on driving, a topic that we have studied for many years, but which has now lapsed with the retirement of Brown and the departure of Groeger. The group has been very active and well supported over recent years, when they have been paying particular attention to the process of learning to drive. One important finding from their careful analysis is the huge difference in amount of practice that occurs across different subcomponents of driving skill. Typically subjects have a great deal of practice on control skills, but much less on skills of decision, particularly about situations in which they need to assess what other road users will do. This work was accompanied by another programme concerned with the judgement of risk, demonstrating that video traffic scenes provide a valid means of assessing the capacity for risk judgement. There are clear implications for ways in which driver training should be changed, and of methods whereby decision processes may be practised and subsequently assessed. Groeger has now moved to the University of Leeds where, I am happy to note, the programme will be continuing. Though our commitment to the analysis of complex, real-life tasks remains strong, with the termination of work in driver behaviour, and Barnard’s increasing commitment to cognition and emotion, overall effort in this area is somewhat diminished. At the same time, the neurobiological aspects of the attention programme are increasingly promising, and complement developments in cognitive neuroscience in Cambridge with establishment of the MRC Brain Repair Centre, the Wolfson Functional Brain Imaging Centre, and the Innes Centre for primate neuropsychology. Through collaborations with these other Cambridge groups, and elsewhere, we expect lively developments in this aspect of the attention programme.

Programme 3: Memory

The capacity to learn and remember plays a crucial role in human cognition, and has always formed an important area of research at the APU. Five senior scientists contribute to the area, although only Bekerian and Baddeley would probably regard themselves as primarily working on memory. Consequently, the boundaries between this and other Unit programmes are often indistinct. For example, much of the research on working memory could be categorised as part of the attentional project, while research on prospective memory and on test development is highly relevant to similar concerns within the rehabilitation group, as is Maylor’s work on memory and ageing, and Murre’s modelling of amnesia, which ties in directly with theoretical work on rehabilitation by Robertson. Links with research on language are equally obvious; a good deal of Bishop’s work is related to short-term and working memory, while Patterson’s work on semantic memory forms part of her general interest in language. Finally, Bekerian’s work again ties in very clearly with the theme of cognition and emotion.

Human memory can be regarded as an alliance of separate but interacting systems that have in common the function of storing information and subsequently making it available when needed. It can be broadly divided into short-term or working memory, involved in the temporary maintenance of information being used to perform other cognitive tasks, and long-term memory. Long-term memory itself can be subdivided into episodic memory, the capacity to recollect specific experiences, and semantic memory which can broadly be regarded as knowledge of the world. Finally, in recent years it has become increasingly clear that we need to distinguish between the previously-described systems which provide information that is explicitly available, and implicit learning and memory, involving the learning and retention of skills and access to information under conditions where the subject may demonstrate learning by performing a task more efficiently, without necessarily having any recollection of the learning experience. Work at the Unit has addressed all of these areas. Baddeley and Andrade have been concerned with developing a model of working memory originally proposed in 1974 by Baddeley and Hitch. Work has concentrated on two components of the model, namely the phonological loop, a system for temporarily maintaining speech-based information, and the central executive, a limited capacity attentional control system.

Much of the work on the phonological loop has been designed to test the hypothesis that it has evolved as a mechanism for language acquisition. Work carried out in collaboration with Papagno and Vallar in Milan, and Gathercole in Bristol, supports this view by showing that: (1) Adults with a neurologically acquired phonological loop deficit and children with a developmental deficit both have difficulty in acquiring new vocabulary. (2) Normal children show a clear association between a task involving immediate phonological repetition and vocabulary development. (3) Variables that are known to interfere with the operation of the phonological loop also interfere with the acquisition of novel vocabulary, but not with the capacity to learn to associate pairs of meaningful words. We are currently testing the hypothesis that the same system is necessary for the acquisition of grammar.

The central executive is the term applied to the system that is assumed to control working memory. It is a complex and almost certainly multi-component system. We are investigating it by splitting off individual executive processes, which we then analyse with a range of methods involving both neuropsychological patients and normal subjects. One postulated function of the executive is to coordinate concurrent tasks. This has been studied in collaboration with Spinnler, Della Sala and Logie in Milan and Aberdeen, principally using studies of patients suffering from Alzheimer’s disease (AD). The method involves titrating the level of difficulty of concurrent visuo-spatial and verbal tasks to a point at which patients and controls are performing at an equivalent level on each task alone. When combined performance is required, AD patients show a disproportionate decrement, whereas the normal elderly show no such effect. As the disease progresses, dual task performance deteriorates substantially more rapidly than single task. We have also modified our original methodology so as to provide a simple paper-and-pencil version, and have replicated our original results. We are now beginning to explore the generality of this deficit and find that it is also present in a particular subsample of patients with frontal lobe damage. Other executive processes already investigated include random generation, in which the subject is required to produce an unpredictable stream of responses, a task that appears to load heavily on the executive. More recently we have been investigating the processes involved in responding to stimuli while ignoring irrelevant items presented within either the same or a different modality. Preliminary results suggest that the capacity to resist within-modality interference is particularly susceptible to the effects of ageing.

In the area of long-term memory, much of Baddeley’s work has been concerned with collaborative research on rehabilitation, and with the development of improved memory tests. These have included a test of semantic memory, based on both speed of comprehension and capacity of vocabulary, while a second test measures episodic memory performance. Visual and verbal recall and recognition are tested using naturalistic material, comprising coloured photographs of doors and sets of people’s names. Preliminary results suggest that the test is highly sensitive, is good at differentiating visual and verbal memory deficits, and furthermore, is enjoyed by the patients. Future research by Baddeley on working memory and long-term memory will form the substance of a separate proposal for work to be carried out elsewhere. Research by Maylor has been concerned with analysing the cognitive changes that accompany normal ageing. A theme underlying much of her work has been the extent to which ageing represents a general overall decrement, and to what extent certain cognitive functions may be disproportionately impaired or preserved. One series of studies required subjects to make judgements about pictures of objects or people, and to produce the appropriate name. Older subjects uniformly tended to respond more slowly, but this deficit was disproportionately large when naming was required. This effect seems to represent the more frequent occurrence of “blocking” in the elderly, where the name was on “the tip of the tongue”. Such a deficit was not found in a selected group of young and elderly experts. Participants in “Mastermind” appeared to show no effect of age on response time, suggesting that up to a point at least, expertise can counteract the slowing in retrieval.

Another area in which the elderly seem to be disproportionately impaired is in experimental studies of prospective memory; remembering to do things. Even when they have demonstrated that they remember the relevant instruction, elderly subjects are still more likely than the young to forget to carry it out when tested under laboratory conditions. Under real-life circumstances however, the elderly tend to be rather better than the young since they make more systematic and effective use of reminders and memory aids.

Maylor’s future work will further investigate the area of prospective memory, in particular focusing on factors that may make this function particularly susceptible to the effects of age, such as the need for self-initiation of action, the demands of concurrent activity, and the extent to which environmental cues can prompt recall. Other research will be concerned with further analysis of the effect of age on retrieval from long-term memory. Finally in collaboration with Wing, she will study the interaction between extent and type of concurrent cognitive activity and postural stability, an important practical problem in the elderly.

Prospective memory also featured in a study carried out by Sellen at Rank Xerox, on memory problems in the workplace, where prospective memory lapses proved to be the major source of reported memory problems. This study led to the development of a new computer-based reminding system that is currently under development by Rank Xerox. The technological capacities of Rank Xerox also allowed Sellen to carry out a more theoretically-based study on factors influencing the prospective memory task of remembering to press a button every two hours, a simulation of pill-taking. Subjects wore an “active badge” that monitored their location and their responses. The results suggest two separate components, one concerned with self-prompting and a second dependent upon environmental cues. Further work will use this technology to study the effect of a range of variables including the extent to which the subject “worries” about performing the task. If successful, the device may well prove useful in studies of cognition and emotion.

The classic topic of memory research is episodic memory, the capacity to recollect a specific experience. This is the focus of the research by Bekerian, who is particularly interested in the study of memory under the naturalistic circumstances that occur when a witness attempts to recall a dramatic incident such as an attempted rape, or a series of incidents such as repeated physical or sexual abuse. Evidential testimony represents a situation in which it is essential to assess the accuracy of recollection, and to avoid the danger of distorting memory through the process of interrogation. Bekerian has investigated aspects of testimony that influence the degree of perceived authenticity, including consistency, spontaneity, and the presence of reported perceptual detail. These features were modulated by the method of reporting; for example, certain interrogation methods encourage the subject to try to visualise the scene, and there is evidence to suggest that this leads to more perceptual detail, some of it erroneous.

Such detail may then give rise to an unwarranted increase in the confidence of the witness and the preparedness of a juror to accept the report. Other factors influencing accuracy include whether recall is spoken or written: written recall seems to lead to a reduction in correctly recalled information, possibly because the more formal response mode encourages a more “polished” product.

Bekerian has worked extensively with the Home Office, the Police, the County Statutory and Caring Agencies and the Regional Health Authority, all of whom are concerned to improve their quality of interviewing, particularly in areas such as that of child abuse. Interviewing for therapeutic or evidential purposes demands very different styles, with the Home Office stipulating that therapeutic-style interviewing should not be used to obtain evidence. Bekerian’s work on the analysis of interviewer behaviour has led to many requests for advice in developing better training of interviewers. Currently, the Crown Prosecution Service are forced to abandon a large number of cases on the grounds of inadequate interview procedure. Such statistics should provide evidence of the success of our attempts to improve interviewing skills. Investigation into methods of evaluating the accuracy of testimony, and of avoiding distortions during the interview process, will continue. The commonly used “cognitive interview technique”, which among other things encourages the use of imagery, is based on theoretical memory research, and does appear to be an advance on previous techniques, but is almost certainly capable of improvement. New lines of development include the reviewing of current practice in investigating serial crime, including the technique known as offender profiling. Bekerian has been requested to compare approaches in Britain with those in the USA, Continental Europe and Australia, and it seems likely that this may well give rise to further empirical work. Finally, a joint interest with Dalgleish (who is about to join the Cognition and Emotion group) concerns the influence of emotion on the memory of patients suffering from post-traumatic stress disorder, in which persistent vivid memories of the incident often form one of the more distressing symptoms.

While episodic memory may be the most striking and characteristic aspect of human memory, semantic memory which comprises the repository for our knowledge of the world is equally important. Karalyn Patterson has been studying semantic memory in collaboration with Hodges of the Neurology Department at Cambridge. They have concentrated on three issues: the anatomical localisation of the system responsible for semantic memory; whether semantic and episodic memory represent genuinely separable systems; and the functional organisation of semantic memory. The work is based on longitudinal studies of the decline of semantic memory in two types of patient:

Alzheimer’s disease (AD) patients, in whom a prominent episodic memory deficit is usually associated with a subsequent decline in semantic processing; and patients with a recently labelled syndrome of semantic dementia, in whom the semantic deficit occurs in a relatively isolated form. Brain imaging studies suggest that the temporal neocortex is particularly important for semantic memory, while differences in the specific location disrupted in the two patient groups hint at the possibility of anatomically separable semantic and episodic systems. Further investigation of this issue will depend upon a more detailed analysis of episodic memory in semantic dementia cases; the issue is not straightforward since, even if semantic and episodic memory reflect separate systems, there is no doubt that they interact.

A study of the breakdown of semantic memory in patients with semantic dementia suggests a consistent pattern, with specific information (such as the fact that dogs bark) being lost before more general information (e.g. dogs are animals). This is compatible with a widely-held hierarchical concept of the structure of semantic memory, but is also open to other explanations. Differences in number of relevant features in a distributed network could make the higher level concept of animal more redundant and hence more robust to partial disruption by brain damage.

Future plans include serial in vivo imaging of semantic dementia patients, followed by neuropathological analysis at post-mortem. Such a strategy will also be pursued with AD patients, with the additional aim of relating the more varied pattern of deficits in these patients to the localisation of neurodegeneration. The issue of whether the decline in semantic memory represents loss of basic semantic representations, or impaired access to relatively preserved representations, will be tackled using measures of consistency across successive tests, an approach that raises some challenging statistical issues. Finally, in addition to detailed exploration of semantic and autobiographical memory in patients during the early stages of decline, it is proposed to develop methods that will allow semantic processing to be assessed during the later stages of dementia. Work by Jean Mandler in San Diego on pre-linguistic babies employs a measure of the time that a baby will spend looking at an object as an indication of its degree of perceived novelty. When four items from a similar general category, for example living things, are presented in succession, presentation of a fifth living thing leads to shorter inspection than presentation of a non-living object. Using this technique, Mandler has shown that babies acquire the living/non-living distinction at a very early age. Patterson and Hodges predict that this distinction will be robust in dementia patients.

Andrew Young, who recently joined the Unit, is also concerned with semantic memory, but is particularly interested in the way in which people are perceived and remembered. Having previously concentrated on face perception, he is interested in the extent to which memory for known faces uses the same underlying cognitive and neural structures. One way of studying this is through an analysis of prosopagnosia, a deficit in face recognition that occasionally results from brain damage. His work has identified at least two types of patient, both of whom experience great difficulty in recognising familiar faces, but who differ in their capacity to generate images of faces. One type of patient is able to form accurate images of faces which are no longer recognised, and hence can answer questions about the appearances of pre-morbidly familiar people, whereas the other has no capacity for imaging faces. This pattern of results suggests a multi-stage system for recognising faces, as do other results obtained before his appointment to the Unit by Young and his co-workers demonstrating that some prosopagnosic patients show implicit recognition of famous faces that they do not report as familiar. This can be demonstrated by showing that presentation of a non-recognised politician’s face will influence the subsequent recognition or categorisation of his name. Future work will develop new techniques for testing the theory both with normal subjects and with patients. Prosopagnosic patients are rare, but it is commonly the case that patients suffering from anterograde or retrograde amnesia have difficulty in face recognition. A detailed examination of such patients will first of all identify any for whom face recognition problems are particularly marked, and will then check whether the deficit is one of recalling the person, which would be reflected in a parallel difficulty in recognising a voice or providing information about a named person, or is specifically visual.

Further studies will exploit the fact that people represent an interesting class of semantic concept, since their visual appearance changes as they age, and new facts about them are being constantly learnt. This allows a test of one of the classic issues of concept formation, that of whether concepts are based on a large number of stored instances, or represent an abstraction from the individual experiences. The former might suggest that it would be easier to associate a picture of a person’s face when young with information from that time, (e.g. that Cliff Richard sang “Living Doll”) than it would be to associate an early photograph with a more recent piece of information. A prominent feature of the Unit’s work on learning and memory over recent years has been an increasing interest in computational, and in particular connectionist, modelling techniques. This powerful new modelling approach, combined with the judicious use of empirical data, allows much more detailed and ambitious models than were possible using a purely descriptive conceptualisation. Interestingly, there are close affinities between recently developed connectionist models of human learning and earlier mathematical models based on conditioning in animals. Work by Shanks has shown that an associative conditioning model of this type gives a very good account of whether human subjects perceive pairs of events as causally related. Shanks has also explored connectionist models of category learning, demonstrating major problems with a standard learning algorithm, back-propagation, and proposing an alternative connectionist model that avoids these difficulties.

Murre has been developing a general connectionist model of long-term memory and forgetting. He begins with the problem of massive interference that occurs in some basic back-propagation models, spelling out a number of ways in which this can be avoided. He has been particularly intent on ensuring that his model is biologically plausible, with the result that it has formed the basis for a collaboration with Robertson to generate the framework for a general model of rehabilitation. Concern with neuropsychological data has led to the first connectionist model of learning that also gives a good account of both anterograde and retrograde amnesia. Research on forgetting has been comparatively neglected over the last 20 years, and Murre’s model should provide an excellent basis for a revival of interest in this important topic. One final area in which connectionism has influenced the Unit’s work is in attempts to model the phonological loop component of working memory. Norris, Page and Baddeley, funded by the Joint Council’s Initiative in Cognitive Science, are capitalising on the fact that modelling the loop involves two of the fundamentally important issues of connectionist modelling: (i) how to represent serial order; (ii) how to capture the process of chunking whereby individual units are aggregated to form larger units, which many models assume to be the basic process of long-term learning. Extensive existing data place valuable constraints on possible models. In addition to developing a connectionist model that gives a good account of the initial data set we have also developed a more abstract mathematical characteristic of the serial recall process which not only gives a precise quantitative account of the data but also helps specify a set of properties which must be possessed by any adequate model of serial recall.

The next issue is that of obtaining a deeper understanding of simulations by mathematical modelling. Houghton’s competitive queuing model, initiated at the Unit and subsequently developed at University College London, has been influential in modelling development. Future work will elaborate the mathematical analysis of the connectionist model, and will concentrate on the question of how items are represented in memory, and how the serial recall process avoids the inappropriate repetition of earlier items while at the same time being able to cope with sequences in which the same item occurs more than once.

Programme 4: Language and Communication This area which is central to the study of cognitive psychology continues to form a major component of the Unit’s programme. Our approach is characterised by the utilisation of a wide range of techniques and subject groups, and by the attempt to blend pure and applied research.

Cutler, who has now left to become a director of the Max Planck Institute for Psycholinguistic Research, and Norris are concerned with the problem of how we segment the continuous stream of a spoken utterance into its constituent words. They tackle the problem using standard experimental paradigms, computational modelling and cross-linguistic studies. A basic hypothesis, the Metrical Segmentation Strategy, proposes that prosodic information is used to segment the speech stream, with the details of the strategy depending on the specific language. English rhythm is based on the foot, French on the syllable, and Japanese on the mora (typically a consonant-vowel unit). Stressed vowels have been shown to be longer, louder, and greater in pitch movement than unstressed syllables, while a detailed analysis of the stress pattern of English indicates that a high proportion of words have stress on the initial syllable, making it a valuable cue to segmentation in English. The Metrical Segmentation Strategy is utilised by Norris’s computational model SHORTLIST, which represents the first new model of speech perception for over a decade. Unlike its major competitor, the TRACE model of McClelland and Elman, Norris’s model does not require the duplication of processing networks, and does not assume an interaction between processing levels. His computational model is simpler in assuming only a billionth as many inhibitory connections, and is able to cope with a vocabulary of over 20,000 words, as opposed to 1,000 words for the TRACE model. The model has been shown to account for existing data well, and has been tested empirically in a series of studies in which subjects were instructed to detect words embedded in other words, for example the word CAM in CAMEL, where the results are compatible with the assumption of competition between word representations as proposed by the SHORTLIST model.

Collaborative work between Cutler and Jusczyk has shown that young infants from English-speaking families prefer to listen to words with stress on the initial syllable, suggesting that lexical segmentation is being acquired at a very early age. Future work will evaluate this further, using statistical simulation of the learning process, and utilising the model to investigate the nature of segmentation in more detail. There is, for example, evidence that subjects also make use of statistical characteristics of syllable and word endings. Two basic assumptions of the SHORTLIST model, namely the modularity of its component processes, and its bottom-up rather than interactive architecture, will be subjected to more rigorous empirical test. Finally, studies of the role of syllabic information in lexical representation will be extended to native speakers of French and Dutch in order to assess their cross-linguistic generality. Karalyn Patterson also uses connectionist modelling and cross-linguistic methods to study word recognition and production, but relies more heavily on neuropsychological evidence than do Norris and Cutler. She is particularly interested in the interaction, in various language tasks such as reading aloud, between representations of a word’s orthography (spelling), phonology (sound or pronunciation) and meaning. A major component of her work involves study of the breakdown of language in patients suffering from progressive neurological disease, a programme that is carried out jointly with Hodges from the Department of Neurology in Cambridge. Patterson and Hodges have been particularly interested in “semantic” dementia, a neurodegenerative condition involving focal atrophy of temporal neocortex. Because this condition produces relatively selective loss of semantic memory, it offers the opportunity to study the impact of loss of word meaning on other aspects of language processing. For example, the fact that patients with semantic dementia develop surface dyslexia (a reading disorder producing regularised pronunciations of words with irregular spelling-sound correspondences, e.g. reading pint to rhyme with “mint”) suggests an important interaction between meaning and phonology in reading.

Work on normal subjects has also been concerned with the interaction between orthography, phonology and meaning. Recent work by Patterson and Strain has demonstrated that the speed and accuracy with which normal adults read written words aloud is affected not only by the word’s frequency and typicality of spelling-sound correspondence, but also by a semantic variable, imageability (low imageability words are abstract, high imageability words refer to concepts with many sensory/motor properties). This result again implicates word meaning in the transcoding from orthography to phonology, a task which does not, on the face of it, demand access to meaning. The nature of this transcoding has also been studied in native readers of Japanese kanji, a writing system completely different from alphabetic English, to yield insights into aspects of language processing which are universal and those which are tuned to language-specific characteristics.

Results from normal and impaired English readers play a vital role in evaluating computational models of the transcoding from orthography to phonology. Whereas Norris’ connectionist reading model is principally concerned with simulating normal readers’ response times to name words under laboratory conditions, Patterson’s collaborative work (with McClelland and Plaut in Pittsburgh and Seidenberg in Los Angeles) focuses on the capacity to simulate a range of neuropsychological reading deficits. The model does not yet have a semantic component but is capable, after extensive training, of correctly pronouncing virtually all monosyllabic words, even low-frequency irregular words. When “lesioned”, however, it does not successfully simulate the pattern of reading performance typically observed in semantic dementia—preserved naming of regular words and nonwords, impaired and frequency-modulated naming of irregular words. If the training of the model is stopped at an earlier point, however, a better match to surface dyslexia in semantic dementia is obtained. Future work will explore the hypothesis that degree of skill in spelling-sound transcoding is determined in part by interaction with word meaning.

A third approach in Patterson’s work on language has involved PET scanning, in collaboration with Wise and Price at the MRC Cyclotron Unit and Howard at Birkbeck College, London. Studies of both spoken and written word recognition in normal subjects have revealed maximal rCBF increases in regions at or very near those implicated by lesion studies. A novel finding is the effect of rate of spoken word presentation: although most areas of bilateral temporal cortex show monotonic increases in rCBF with increasing word rate, Wernicke’s area (known from lesion studies to be specialised for spoken word recognition) is maximally activated even at slow rates. Future functional brain imaging work will take advantage of the fact that techniques are now capable of dealing with single-subject data, making neuropsychological case studies feasible. The role of the right hemisphere in language processing will be investigated with single-subject data from normal subjects and patients with a variety of sites/sizes of left-hemisphere lesions.

Further work on semantic dementia will concentrate on the role of meaning, not only in language tasks (such as word and sentence repetition, and lexical decision), but also in non-language abilities such as object recognition. The progressive decline of language and other cognitive abilities in Alzheimer’s disease also provides a valuable source of information about the interaction between different domains of representation. The completion of a three-year longitudinal study carried out jointly with Hodges, with approximately 30 Alzheimer’s patients tested at six-monthly intervals on a wide range of tasks, will yield a rich database for hypothesis testing on the structure of language and its decline. Work with Tyler (at Birkbeck College, London), using on-line measures of spoken language processing, is beginning to provide significant advances in the study of both the nature of the meaning loss in semantic dementia, and the separability of semantic and syntactic components of language.

New work will concern aspects of speech production in patients with another form of neurodegenerative disease—progressive nonfluent aphasia—involving deterioration of phonology and syntax but relatively preserved single-word meaning. Similar longitudinal analyses will be made of patients with progressive anomia, whose spontaneous speech is fluent but “empty” of specific content words. Our current studies constitute the first systematic experimental analysis of progressive nonfluent aphasia, and both types of patients are yielding results germane to models of speech production. Collaborations with neuropsychological colleagues in Japan will once again enable evaluation of the generality or language specificity of some of these findings. For example, the reading performance of Japanese patients with semantic dementia will be assessed for parallels with surface dyslexia in English. While Patterson is using the breakdown of language in neurodegenerative disease as a way of understanding its normal operation, Bishop is learning about language processing by studying failures of acquisition in children with specific language impairment (SLI). Although SLI is a clinical problem of some magnitude, it is still poorly understood, being associated with a relatively wide and varied pattern of symptoms. Bishop has used a twin study to investigate the aetiology of SLI, the existence of sub-types and their cognitive basis. Some 90 pairs of same-sex twins were selected on the basis that at least one of the pair has significant language problems, performing at or below the 10th centile on one of four carefully-chosen language tests. The importance of an inherited factor was indicated by the higher concordance (54%) in monozygotic than in dizygotic twins (30%). There was no clear association with other medical problems, other than toxaemia, a poorly-understood disease of pregnancy which may possibly be serving as a marker for other immunological abnormalities. Future work in this area will use the twin study method to try to obtain a better definition of the SLI phenotype, in particular attempting to decide whether it represents a qualitatively distinct disorder, or a quantitative departure from normality. The issue of heritability of language skills in the normal range will be investigated by testing a normal sample of monozygotic and dizygotic same-sex twins. Data from the SLI twin sample will be further analysed to study the link between language, literacy, motor development and handedness. This sample will also be used to try to identify the best marker for SLI, in particular testing Tallal’s proposal of a deficit in rapid serial processing, Gopnik’s suggestion that syntactic problems are fundamental, and the proposal by Gathercole and Baddeley, and by Bishop herself, that a deficit in working memory might be critical. One problem in dealing with SLI is that of identifying some of the subtler components of language deficit. In “semantic-pragmatic disorder” the child is fluent but verbose, showing poor comprehension and a tendency to interpret language literally, together with difficulties in the more social aspects of conversation such as turn-taking.

Bishop and Adams in Manchester are developing a method for conversational analysis that aims to pinpoint such problems, using precise and reliable coding. Future work will investigate the extent to which a deficit in social interaction might be fundamental, using tests of nonverbal behaviour and “theory of mind” tasks taken from the study of autism. Preliminary evidence is not encouraging for these hypotheses, however, suggesting the possibility of some form of more general attentional deficit. It is proposed to modify some of Duncan’s tasks for use with children so as to investigate the attentional deficit hypothesis.

Preliminary work on the grammatical deficit in SLI suggests that it does not represent a systematic and specific deficit, since the same grammatical rules will be followed on one occasion and broken on another. The fact that the likelihood of error increases with the length of utterance suggests that the difficulty may be a limitation of general processing resources. Future work will test this in a number of ways. SLI children will be required to repeat sentences varying in length, with and without inserted errors, and will be required to judge their grammatical correctness. This will allow a more precise test of the hypothesis that errors occur when processing load is high. Another way of testing this hypothesis is to combine sentence repetition with a demanding non-verbal task; again the prediction is that grammatical errors should increase in SLI children. Finally, it is proposed to use the methods of language analysis developed from SLI children to study language and communication in a wider range of conditions. For example, work with Skuse at the Institute of Child Health in London will apply the methods of conversational analysis to children suffering from Turner’s syndrome, who typically show a mature interactional style but have difficulty in making friends, suggesting a subtle deficit in social interaction. The more complex communicative aspects of language are also the concern of Wright, although in her case the focus is on written communications rather than with face-to-face spoken interactions. When people use written materials to accomplish a task they need to find the relevant information, understand and remember it, then act on that information. Changes in document design can be used to explore how people integrate these cognitive activities. One component of Wright’s programme, concerned with issues of understanding, has examined the way in which readers and writers use such graphic supports as sketch maps and diagrams. She has found two kinds of graphic-text relation that differ in their effects on comprehension if readers study the illustrations while reading the text. Graphics explaining textual details can hinder readers trying to follow the main thread of the text; graphics that offer an organising schema for the text repay study during the course of reading. However, readers do not distinguish these graphic roles and adopt a single strategy of studying the graphics either before or after reading. Document design can encourage readers to change their strategies, allowing the possibility that the design can be tailored to create the optimal reading strategy. However, it was found that writers also adopted inappropriate strategies when giving directions about a route to be taken. They did not spontaneously provide aids such as sketch maps, although they recognised that these would facilitate communication. These studies point to the complexity of the communication skills needed by adults working with written information and graphics. One situation in which it is often necessary to combine verbal and visual forms of communication is in finding one’s way in an unfamiliar environment. Here the focus is on the application of the knowledge gained from reading. In a study concerned with route-finding by patients within a large hospital, provision of a map led to more satisfaction and less re-tracing of the path than relying on the hospital signposting. This occurred despite the fact that use of the map did not lead to more rapid arrival at the destination, because people with the map chose to spend time planning their route and considering alternatives. Thus speed may not always be an appropriate indicator of good information design. Instead, good design needs to meet all the purposes for which people will want to use it. An incidental finding during this research was that one source of problems for hospital signposting is the way in which the same location can be described in different ways, Room C120, the Eye Clinic and Dr Smith’s Clinic for example. Emphasising one of these in the appointment letter and using this label on hospital signboards would simplify the problem.

Another component of Wright’s programme has examined readers’ strategies for finding information within electronic documents where readers can move within the texts in new ways, jumping immediately to related information. Readers compared information from different parts of a text in order to reach a decision. It was found that their choices about how to move within the document were determined by perceptual factors, such as the spatial relation between text windows on the computer screen, even though this sometimes resulted in a search pattern that made it more difficult to remember the information found. Similarly, the inclusion of verbal information in pop-up windows changed its status within the discourse structure of the text and so enhanced subsequent recall. These studies of search strategies show the interplay between information design and readers’ allocation of cognitive resources. Work on creating usable written communications has wide potential applicability, but presents the problem of how such information should itself be communicated to the potential user. Wright devotes a good deal of her time to this issue, contributing to seven British Standards for documentation, and delivering invited talks and keynote addresses to a wide range of professional groups outside psychology. Future research will continue to investigate the roles of graphics in text, extending the work to instructional materials, because the need to create plans for action changes the nature of the dominant cognitive demands on readers, demands which may be met or hampered by animated graphics. When people follow complex multi-step instructions, segmentation into appropriate constituents will help both comprehension and memory. Wright will investigate whether adults do this spontaneously, and if not whether appropriate design can encourage them to do so. A different way of giving instructions is to provide a model of the performance required and ask people to follow it. This technique is often used to encourage people to write in a certain style, although the model given is of the product rather than the performance. This kind of instruction-giving will be explored in order to determine whether people simply imitate the surface features of the model or whether they can abstract the underlying discourse structure. Work will continue on how people search within electronic documents, but the search tasks will be broadened to include multi-featured targets. Electronic documents allow a rich array of search strategies to be investigated using both verbal and iconic materials, and also a variety of document structures including tabular arrays. This work will contribute to existing theoretical accounts of readers’ search activities which have so far considered only printed, linear documents such as student textbooks. Green is also concerned with the role of communication, and in particular in the analysis of non-linguistic artificial communication systems such as diagrams, tables and programming languages, and their use in the increasingly large array of “information artifacts”, such as personal calculators and word processors. Green attempts to identify what he terms “structural features” that are applicable to any well-defined information artifact, from timetables to music scores. The success of his attempt is measured by its capacity to deal effectively with a wide range of very different systems. For example one desirable aspect of any notational system is that it should be “role-expressive”, that is it should allow one to break the system into an appropriate hierarchy of subsystems. Applying this characteristic to the programming languages Prolog and Pascal, Green predicted that Prolog was less role-expressive, and hence should give greater difficulties even to experienced programmers. He tested this by giving programmers specific programs with components snipped out. Their task was to restore the appropriate pieces. As predicted, the Prolog programmers took longer and were more slowed down by increased complexity.

Another study tested the conventional wisdom that graphics communicate more effectively than text. A “box and wire” notation from a widely used graphical programming language (LabVIEW) was compared with a verbal equivalent. It was harder to comprehend and led to more errors, probably because it overloaded the subject’s working memory to a greater extent. Another concept from Green’s analysis is that of “viscosity”, the extent to which a system resists local change. For example, a word processing system might have the characteristics that changing section numbers had extensive knock-on effects, creating problems in the index references etc. Using an existing computer science technique termed “entity-relationship modelling”, Green has developed a measure of viscosity. Future work will develop this analysis and apply it to further types of information display, including various forms of graph. Possible ways of dealing with viscosity problems, for example by introducing intermediate levels of abstraction, will be investigated.

The essence of Green’s approach is that it should be applicable across a wide range of domains, and future work will involve extending it to new applications. It is proposed to collaborate with colleagues at the University Department of Architecture on computer-aided design (CAD) systems for creative architectural design. A range of small demonstration devices will also be constructed, for example bibliographic systems that illustrate the effects of low and high viscosity. Finally, attention will continue to be paid to the issue of communicating to the wide and varied range of potential users. In particular, it is proposed to develop a teaching package that will illustrate the methods that have been developed, evaluating the package using Open University students. A final area of research in communication concerns the development by Rank Xerox of videoconferencing systems, and their evaluation. Sellen has compared face-to-face communication with three different conferencing systems, each communicating different aspects of the participants, from voice-only to systems which use multiple cameras. The only major difference observed was between face-to-face conversations and the rest. Conversations mediated by technology all induced a more formal style of interaction, with fewer interruptions and a more studied handover of the floor from one speaker to the next. A related project concerned collaborative working, either face-to-face, or on remote stations linked by up to four video cameras. Subjects sometimes found the additional camera information useful, but had difficulty in reaching a joint frame of reference, underlining the importance of “common ground” in efficient communication. Future work will extend this research to field studies of video links between Welwyn and Venray in Holland for the distributed design and manufacture of photocopiers. The study will be principally observational, and will investigate issues like adaptation to the system over time. It will, however, also be possible to carry out experiments, for example allowing subjects to select amongst different views of the remote site.

Programme 5: Neuropsychological Rehabilitation

This is the newest research area at the APU. It is developing along the lines proposed in our last Progress Report, and approved by the Visiting Subcommittee who recommended additional posts and funding. The recommendation came at a time of considerable financial pressure, and the Strategy Committee decided that the initial development should be funded out of the Unit’s existing budget, with an encouragement to return for further funding once the programme was established. We believe that we have reached that point, and will be requesting the additional support proposed. The programme has made an excellent start scientifically, despite substantial logistic problems. At the time of our last Progress Report, Addenbrooke’s Hospital had offered to provide space, as part of an ambitious development of their somewhat limited rehabilitation service. The promised space was, however, reassigned as part of the pre-election campaign to cut NHS waiting lists, and only now after several years of postponement does it seem that we shall finally be moving the Rehabilitation group into adequate accommodation at Addenbrooke’s. The proposed expansion of clinical rehabilitation has still not occurred, but fortunately this was less critical than seemed likely because of the substantial increase in strength of the Clinical and Neuroscience Departments at the University Medical School. We have excellent and productive research links with Neurology, Neurosurgery, Psychiatry and Anaesthetics, while the development of the Interdisciplinary Research Centre in Brain Repair and the upgrading of Neuroimaging facilities are likely to strengthen our links with Clinical Neurosciences. Finally, the Lifespan Trust, which is responsible for health in the community in the Cambridge area, plans to develop a model Neurorehabilitation Unit for post-acute patients, with Wilson serving as Scientific Director. In the meantime, Wilson and Robertson have been able to compensate for the comparative paucity of local rehabilitation facilities by collaborating with colleagues elsewhere.

The Rehabilitation group have focused their attention on the assessment and treatment of brain injured people, attempting to analyse the role of neural plasticity and re-learning in their recovery. We have chosen to focus on cognitive deficits in memory and attention since these are both pervasive symptoms of brain damage which are not only intrinsically undesirable, but in addition are likely to interfere directly with any attempt at rehabilitation. They also represent topics that are of central theoretical concern to the Unit, with the result that there is very active collaboration between the Rehabilitation section and colleagues whose work is principally reported elsewhere. Consequently, the question of whether a particular piece of work is reported as part of the work on rehabilitation, or as research on attention or memory, is to some extent arbitrary.

Wilson’s work can be divided into three related themes. The first of these concerns the detailed observation of the natural history of recovery from brain injury, which forms a basis for the second theme, namely that of developing better methods of assessment, which in turn feed into the third aspect, improving methods of treatment. Although we know a great deal about the sequelae of various types of brain damage, much previous work is based on cross-sectional studies, with very little attempt to monitor the same patient over a substantial period of time. Wilson has been carefully following up patients that were seen and studied in depth during her period at Rivermead Rehabilitation Centre, Oxford (1979-85). These studies have generated important baseline data regarding natural recovery of function in different cognitive domains, and such data will be crucial for the theoretical understanding of the processes underlying recovery and rehabilitation, and for the practical goal of optimising existing rehabilitation regimes.

One example of this detailed observation of natural history comes in a joint study with McLelland and Shiel at Southampton who used the careful observation of patients recovering from severe head injury as a basis for developing a standardised assessment usable from a state of coma through to the point at which other more conventional neuropsychological tests can be deployed. Particularly during the early stages, signs of recovery can be quite subtle, often resulting in the erroneous conclusion that the patient is not improving. Extensive longitudinal data on 88 patients have been collected, and are currently being analysed with a view to standardising scales that should prove helpful in patient monitoring and in prognosis. Two other lines of research have stemmed from this study. The first concerns the issue of whether learning can occur in coma; evidence suggests that it can, and that it may have implications for training methods that may minimise undesirable features such as contractures. The second has concerned a more detailed analysis of the confusional state known as post-traumatic amnesia (PTA). Length of PTA is commonly used as a predictor of probable outcome, but its accurate measurement is acknowledged to be problematic. Studies at Southampton and subsequently with Boismeir in the Department of Neurosurgery in Addenbrooke’s are providing a much more detailed account of PTA, and it is hoped will lead to the development of better methods of assessment. The developments in understanding of memory function at the APU and elsewhere have furthermore led to the construction of tests which incorporate facets of memory hitherto largely ignored in clinical memory testing, such as, for instance, prospective memory (remembering to do things at the right time). It is perhaps this combination of the use of everyday materials together with theoretical sophistication, which has led to the strongest correlations yet found between a clinical test (in this case the Rivermead Behavioural Memory Test, developed by Wilson et al) and real-life functional memory performance and adjustment.

Wilson and colleagues are pursuing work on this and other facets of the memory system in developing a specific test of prospective memory based on a paper-and-pencil text-based procedure, where the reader must obey instructions at some later point in the text. Preliminary studies in normal ageing on this test are promising. Wilson is also collaborating with Burgess in London and Alderman in Northampton in developing the BADS test (Behavioural Assessment of Dysexecutive Syndrome), influenced by Shallice’s work on the frontal lobes and Baddeley’s concept of working memory. Preliminary data are encouraging, and norms are now being developed.

In general, this approach to clinical testing which Wilson and colleagues have developed has been very successful and influential worldwide. For instance, the RBMT is now used in some 17 different countries in 11 languages, and versions for children and Down’s syndrome have been developed.

In the area of treatment, much of Wilson’s work has focused on a technique known as “errorless learning” in which the learning task is structured so as to avoid allowing the subject to make mistakes. This approach was developed in the animal learning field many years ago and has had some application to learning in mentally handicapped people. Its possible value in helping patients with memory deficits was suggested by Baddeley and Wilson, who argue that one of the major functions of explicit episodic memory is that it allows the organism to avoid errors. Amnesic patients who lack this memory system will therefore tend to be captured by their own erroneous responses, with each incorrect response making it more likely that the same error will be made again. An experiment designed to test this prediction indicated that amnesic patients were indeed particularly susceptible to disruption by earlier errors. A series of single case studies have demonstrated that errorless learning can be used with advantage across a range of patients and a range of tasks, from learning names to acquisition of the skill needed to programme a memory aid. It is equally clear, however, that the method does not always work in a simple and straightforward way, and it is proposed over the next few years to explore the theoretical basis of the errorless learning phenomenon at the same time as assessing its generality across patient groups and materials.

A particularly promising potential development over the next few years is the proposal that Wilson acts as Scientific Director to a new Rehabilitation Unit to be created by the Lifespan Trust. The Unit will deal with some 15 post-acute patients during the period between leaving hospital and returning to work. The Unit will be modelled on similar units in the USA and Denmark, and its success will be evaluated in collaboration with Stilwell of Warwick who is currently responsible for the assessment component of the Department of Health National Brain Injury Study. In addition to providing an ideal environment for developing and evaluating rehabilitation practice, the proposed centre offers a promising novel method of interaction between the Council and the NHS. Robertson’s principal concern is with attention and its disorders. His programme of work ties in closely with that of Duncan’s group reported in the Attention section, and to a lesser extent with the attentional control components of the work on cognition and emotion. Robertson takes as his theoretical basis evidence from a range of sources, including PET scanning that suggests that, in addition to the competitive processes underlying attention proposed by Duncan, there is a need to propose the existence of at least three supramodal attentional systems, for selection, sustained attention and spatial orientation respectively. One must also assume that deficits in these attentional systems strongly determine recovery of function following brain damage, given that much recovery of function depends on learning, which itself is heavily influenced by available attentional resources. Robertson has developed a clinical test of these different attentional processes, using the same principles as espoused by Wilson, namely of combining everyday materials with theoretical structure in clinical test development. The Test of Everyday Attention (TEA), using such materials as maps and telephone directories, has a factorial structure (based on a standardisation sample of 154 normals) which indeed supports the PET and other evidence about the existence of separable attentional control systems. Furthermore, in a population of stroke patients, performance on certain subtests of the TEA at two months post-stroke significantly predicted recovery of functional independence and everyday life abilities at eight months post-stroke. This result provides the first evidence of a theoretically-predicted link between attention and recovery of key physical functions following brain damage. The test is about to be published.

In the past, rehabilitation has all too often been based on the ad hoc application of pragmatic techniques aimed at relieving symptoms. Robertson, in collaboration with Murre, has proposed a theoretical framework for understanding the process of neuropsychological recovery, a framework that was strongly influenced by Duncan’s work, and by Murre’s interest in connectionist models of learning and memory. They suggest four ways in which performance may be disrupted, together with ways of alleviating this disruption.

(1) Overall level of sustained attention or arousal may be too low. They have developed metacognitive, self-instructional methods to train patients to increase sustained attention.

(2) A neural circuit may be malfunctioning, but may be supplemented by the activation of related compatible neural circuits.

(3) The operation of a malfunctional neural circuit may be exacerbated by competition from intact circuits. This inhibitory competition can be reduced by inducing even minimal responses from the impaired circuits.

(4) Subjects may have dysfunctional automatic control of action, but this can be supplemented by the development of conscious strategies. Evidence for each of these sources of disruption and methods of treatment have been investigated and are being further explored and developed. The right hemisphere-based sustained attention system may have particularly strong connections with the right hemisphere spatial orientation system which malfunctions in unilateral neglect. To demonstrate improvements in neglect in response to non-spatial sustained attention training would therefore provide a theoretically important piece of evidence as well as a clinically novel and useful strategy for training both unilateral neglect and sustained attention. In a study carried out jointly with colleagues in Stockholm and Southampton, patients were taught a self-instructional procedure that brings phasic arousal under verbal control. After five one-hour treatment sessions, subjects showed reduced neglect, and enhanced performance on the TEA. Another study using an attentional control procedure identical to one used by Teasdale with recovered depressed patients, also appears promising in producing performance enhancement in head injury patients together with self-reported improvement in everyday functioning. Both these lines of research will be followed up using more extensive group studies.

Robertson’s work fits closely with Duncan’s view of the role of competition and integration of neural circuits in attentional control. One example of this approach draws on the evidence that there are three separate but interconnected spatial circuits for body (personal) space, near-body (reaching) space and far (locomotor) space. Patients who show left neglect following a right hemisphere stroke can be taught to reduce the extent of the neglect by active movements of the left hand in left hemispace. Neglect is not diminished when the movement is passive, or when the left hand moves in right body space, or the right hand is active in either right or left body space. The nature of the action is also critical, with reaching and grasping causing more enhancement than simply pointing. Future work will examine these findings in more detail, in particular separating out neglect of stimuli versus neglect of output. A clinical trial will be carried out in collaboration with McMillan at the Wolfson Rehabilitation Centre, testing a Limb Activation Device which is located in the neglected field and emits a signal at irregular intervals to which the subject is required to respond with the neglected limb. Preliminary results are encouraging, but the planned more extensive study will give clearer evidence of the clinical viability of the method. Work on reducing competition effects is closely related to the research of Duncan and Goodrich who are studying the phenomenon of extinction, whereby the detection of an object in the contralesional field can be prevented when a competing ipsilesional stimulus appears. Robertson has shown that the extinction phenomenon applies also in the motor domain, and that the neglect-reducing effects of left hand movements are abolished when the right hand is simultaneously moved, as the competition hypothesis would predict. Robertson has also shown that left neglect patients veer to the right when walking, but that this can be corrected by left hand movements while walking. This result can also be interpreted in terms of the competition hypothesis, namely that the cortical activation underlying the left hand movement, reduces competition from the undamaged left hemisphere of the brain. Robertson proposes to investigate the therapeutic implications of competition-reduction in other areas of perceptual deficit, as well as in non-spatial attentional problems.

In collaboration with Duncan, Robertson will study the problems of attentional control in patients suffering from frontal lobe damage. Duncan’s concept of goal neglect will be investigated, and the general framework of competitive circuits used to generate and test methods of attentional control.

Work in this area has so far relied principally upon behavioural measures. The integrated competition model of rehabilitation proposed by Robertson and Murre does, however, make very specific predictions as to the underlying neural consequences of damage and treatment. Robertson and Duncan plan to take advantage of the planned development in PET scanning and fMRI in Cambridge to test the model more directly. For example, it is predicted that left-hand grasping in left visual neglect patients will have effects on bloodflow that extend substantially beyond those of simple motor activation, and that these effects will be abolished when the grasping is bilateral. Finally, if our research in the area of rehabilitation is to have any impact, then it is essential that it is communicated to therapists who are in day-to-day contact with patients. Many of these will be occupational, speech or physiotherapists who would not be expected to read the psychological literature in which our results are published. For that reason it is essential that Wilson and Robertson devote at least some of their time and effort to dissemination. Both have great strengths in this area and are in constant demand for delivering workshops and addressing groups of clinicians and therapists, as well as receiving many requests for advice on either clinical or research issues. The fact that they are able and willing to provide this vital link with the clinical community bodes well for the future influence of this component of the Unit’s work.

Programme 6: Cognition and Emotion

Over the last decade, the Unit has played an active role in linking cognitive and clinical psychology. We have been concerned with the way in which the emotions influence attention and memory, and how they are themselves modulated by such cognitive processes, in the case of both normal and clinical populations. Such a development had two aims, to provide a broader and more complete understanding of cognition, and to help guide the development of better methods of treating emotional disorders. We have made good progress in the first of these aims, which is already beginning to feed through to the difficult, but enormously important second goal. Mathews and his colleagues in Cambridge and elsewhere have been concerned to understand the nature of the symptoms associated with anxiety, and have studied both patients suffering from anxiety disorders, and also members of the general public who volunteer to participate in studies of “worriers”. Anxious patients rate the subjective likelihood of negative events as higher than non-anxious subjects, and are more likely to interpret ambiguous events in a negative way. They are also more distracted by such stimuli; for example when required to name the colour of the background on which a word is printed, anxious subjects are slowed down by the presence of a negative word such as cancer, an effect that occurs even when the word is presented so briefly that it cannot be consciously identified. When the anxiety disorder is treated, then the difference between patients and controls disappears. Worriers resemble anxious patients in rating the likelihood of bad things happening to them as higher than do control subjects. They are also poorer at giving reasons why such calamities might be unlikely, but when they are successful in doing so, this does influence their estimate of future probability of such negative events, suggesting a possible line of treatment for excessive worry.

Although anxiety has marked and consistent effects on the likelihood of attending to negative events, anxious patients do not consistently show any greater tendency to recall negative items. Nor do they take any longer than controls to decide whether a given word such as cancer is pleasant or unpleasant. This pattern of results suggests an overall hypothesis. It is necessary for survival for an organism to be vigilant for potential sources of threat, and for the level of this vigilance to be increased at times of danger. Patients suffering from generalised anxiety demonstrate a chronically vigilant style in which there is a bias towards the automatic selection of stimuli of a potentially threatening nature, which in turn is likely to increase further the level of anxiety and maintain the bias. Although negative stimuli are preferentially encoded, processing such stimuli in depth may be inhibited, with the result that the bias does not show up in memory measures or in the results of conscious evaluation of words. Future work will examine in much more detail the nature of the process of detection, contrasting judgements of the pleasantness of a briefly presented word with its direct identification, and studying the effects of a secondary task on the processing of pleasant and unpleasant words by anxious and control subjects. If the bias has its principal effect at a relatively automatic preattentive level, then it should show more strongly in judgements of pleasantness than in word naming; in contrast, a later locus would predict that such a bias would be more obvious when the subject’s executive capacity is reduced by the requirement to perform a concurrent task. Other work will be concerned with methods of reducing the biasing effect. Another line of work, particularly involving Dalgleish who is joining the Unit from the Institute of Psychiatry, will be concerned with the relationship between memory and anxiety. Failure to observe that anxious events are better recalled is less straightforward than might at first appear, and in post-traumatic stress disorder vivid memories of an extremely stressful event such as a rape or an accident can often be one of the more distressing symptoms. As will be clear from the section below, patients may develop a style of retrieval from memory that reduces the level of anxiety in the short term, possibly by consciously inhibiting the memory, but at the expense of longer term adaptation to the stressful event.

Work by Williams identified the tendency in parasuicide patients to have difficulty in retrieving specific autobiographical memories. When asked for specific recollections, such patients typically can only come up with rather general memories, such as “being with my girlfriend”. This pattern is associated with hopelessness, with poor performance on a task requiring the production of effective solutions to practical problems, and with poor prognosis; such patients tended to be still depressed some seven months later. Overgeneral memory has now been observed in other centres elsewhere in the UK and abroad. In addition to research on depression and parasuicide, work by Brewin at the Institute of Psychiatry for example, has shown that overgeneral memory is found in women who have suffered sexual and physical abuse. Work by McNally at Harvard has found similar deficits in Vietnam veterans who have post-traumatic stress disorder. The pattern of data emerging from these studies suggests that overgeneral encoding and retrieval even of neutral events represents a long-term cognitive style which may arise early in the development of response to traumatic events. Such a style could be mimicked, however, by reduced working memory capacity at the time events are being retrieved. The combination of a long-term overgeneral memory style and reduced capacity at retrieval is particularly disabling. Williams’ work is likely to be important since many cognitive treatments depend on the capacity to access specific memories in order to restructure the self-image, and as part of strategies for training and solving social problems. He has moved to UCNW BANGOR, but is continuing this line of research and continuing to collaborate with colleagues at the APU (see below). Depression is a major disease, both in terms of the suffering it causes, and because of its economic consequences, in terms of absence from work, and impaired productivity while working. It forms the focus of Teasdale’s work which has been strongly influenced by Barnard’s Interacting Cognitive Subsystems (ICS) model. Collaborative work between Teasdale and Barnard has led to an important new development which incorporates the influence of emotion on the operation of the model. This has been published as a monograph which is already attracting a considerable amount of interest because of the way in which it provides a fruitful interface between cognitive psychology and issues of clinical practice.

Prior to ICS, attempts to relate cognition and emotion had been dominated by two views, one from a cognitive psychologist, Bower, and the other from a clinician, Beck. Bower conceptualised emotions as additional nodes within an associative net, while Beck linked emotion into a unitary propositional model of meaning. Teasdale and Barnard’s model recognises two kinds of meaning, a “propositional” level that allows the manipulation of semantic representations and concepts, and a second more holistic “implicational” level. Affect is directly linked only to the more general level of representation. This implicational level is directly accessed by body state and sensory information, and is responsible for emotionally-held beliefs, which can of course be quite different from what one rationally knows. As a result of experience, we build up complex schemata or models of ourselves, and in the case of depression, such models may well be highly dysfunctional – “myself as worthless” for example. Convincing the subject rationally that this is not true may influence propositional representations, but only experience will create a similar change within more holistic implicational representations. The process of cognitive therapy can be seen as a means of achieving this deeper change.

One line of research has attempted to contrast this view that affect is linked to a schematic level of representation with the earlier associative network model of emotion. Subjects were required to complete statements about the world that are assumed to reflect dysfunctional models, where the dysfunctional completion word is not one that would be likely to be associated directly with a negative emotion. For example, depressed and control subjects were invited to complete sentences such as “Always to put others’ interests before your own is a recipe for—”. Depressed subjects tend to respond with a term like “happiness”, whereas controls are more likely to produce “disaster” as a completion. This argues against a simple associative model of emotion, which would predict a negative word-completion response from depressed patients, and supports a model based on more complex schemata. Another approach to teasing out the dysfunctional schemata associated with depression was produced by Barnard, in collaboration with Murray at the Winnicott Unit in a study concerned with the interaction of depressive mothers with their young children. The study analysed the spoken discourse of children playing with dolls in a family situation, using a psycholinguistic technique known as case grammar analysis. The study concentrated on one sub-unit of analysis, animate nouns, which can fulfil a number of case roles including agent, object, experiencer and dative. Children of depressed mothers were consistently less likely to refer to themselves in the agent role than were control children, and more of their self-references were phrased with negative form. Barnard is continuing this work as part of a programme grant to Murray studying the stability of the effect over time and its association with later dysfunction. He also plans to use the method to study depressive adults in different mood states, in particular contrasting the depressive, neutral and manic phases of manic depressive patients. The technique would appear to have considerable promise as an indirect measure of psychological dysfunction.

A major factor in the maintenance of depression appears to be the stream of ruminative negative thoughts that patients often find difficult to break out of. Teasdale has been concerned to understand this process, using both a working memory model, and subsequently ICS. He began by studying the intrusion of irrelevant thoughts in normal subjects observing that they were reduced by a concurrent memory load and appear to be associated with the operation of the central executive, rather than with the visual or verbal slave systems. Consistent with the notion that thought production and tasks making high demands on central executive functions compete for the same limited resources, the occurrence of such thoughts was associated with a reduction in randomness in a random generation task. Equally, the capacity of a task to inhibit them decreased as practice made the task more automatic. This pattern of results links the model with a range of attentional training techniques that have been found to be helpful in teaching patients to cope with pain and stress, and which form part of a study concerned with prevention of relapse in patients treated for depression. While treatment of depressed patients with appropriate drugs can be very effective, residual symptoms may occur, and when they do so, as many as 78% of patients may relapse within the next nine months. As part of the MRC Neurosciences Approach to Human Health Initiative, Teasdale is collaborating with Paykel in Cambridge and Scott in Newcastle in a clinical trial of depressed patients with residual symptoms.

This study compares long- and short-term outcome for patients treated either with drugs or with drugs supplemented by cognitive therapy. Both practical and theoretical aspects will be studied. While there is some evidence to suggest that cognitive therapy leads to a lower relapse rate than antidepressant drugs, it is of course expensive in terms of therapists’ time. Teasdale, in collaboration with Williams and with Segal in Toronto, is concerned with attempting to develop and evaluate methods of attentional control which can be taught to the patient relatively easily and subsequently used with a minimum of further supervision. Similar measures are being evaluated by Robertson as a means of helping head injured and stroke patients to manage their attentional and emotional problems more effectively.

Such work on prevention of relapse will continue over the next five years, and will be supplemented by studies based on the ICS model. Teasdale will test the hypothesis that cognitive treatments of depression are essentially concerned with normalising dysfunctional thought patterns, and that to do so requires the patient to develop an alternative store of less depressogenic thought structures. A range of new techniques for measuring such structures and their change are currently under development. Two new lines of research in this area will result from the appointment of new staff members. Dalgleish will be continuing to study the link between emotional factors and long-term memory, as mentioned above, but will in addition be investigating the effects of emotion on reasoning, beginning with simple syllogism problems which have been shown in normal subjects to be influenced by semantic as well as logical factors. He will begin by exploring whether syllogisms based on factors such as self-worth are particularly vulnerable to distortion in depressed patients. If so this should provide a tool for measuring both dysfunction and recovery, at the same time as giving a method for exploring the nature of the distortion.

Andrew Young who has recently joined the Unit from Durham has worked extensively on the perception and recognition of faces. He has become interested in the question of whether recognition of emotion involves a separate system from that required for processing personal identity. Evidence for such a view comes from the study of an amygdalotomy patient with a specific deficit in the capacity to identify emotional expression. Future work will follow up this and related cases, investigating whether failure to identify emotion from the face will be accompanied by a similar failure to make voice-based emotional judgements. Other studies will be concerned with the suggestion that patients with frontal lobe damage may have difficulty in judgements of facial emotion, and with the development of methods and material for the analysis of emotional judgements in normal subjects. Young suggests that a mismatch between the systems responsible for registering facial identity and facial emotion may be reflected in certain syndromes of delusional misidentification. Patients suffering from the Capgras syndrome believe that those surrounding them have been replaced by impostors, while patients suffering from Cotard delusion believe that they themselves are dead. One hypothesis is that, while recognising the identify of surrounding people, emotional reactions based on the face are distorted, a state of affairs which may induce a suspicious patient to suspect that others have been changed, and a depressed patient to attribute the change to himself. Collaborative work is underway to investigate this hypothesis.

It is clearly the case that facial expression and body posture represent an important channel for communicating socially and emotionally significant information. Research on human-computer interaction using simulated faces and voices has begun to demonstrate the extent to which a person’s attitude and behaviour can be influenced by cues that are sufficiently subtle that the subject fails to detect them. One aspect of Barnard’s work will be exploring this, and relating it to the work of Young on the perception of emotion by normal subjects and by neuropsychological and neuropsychiatric patients. This area of research is still in its infancy, but has considerable promise for understanding the problems of certain patients in interpreting their social environment, and in transmitting the social signals that, although implicit, are crucial for successful social behaviour.

The progress report for 1990-94 covered work appearing in some 861 papers, reports and theses. Alan Baddeley made known his intention to retire from the Directorship before the 1994 Progress Report. After moving to the Psychology Department at Bristol University, he retained a guiding role in the scientific direction of the APU until William Marslen-Wilson took up the post of Director in July 1997. The scientific programmes and resources were re-organised and, in order to reflect these changes, from April 1998 the Unit was re-named the Cognition and Brain Sciences Unit (CBU).

Published material on the History of the APU:

Baddeley, A. and May, J. (1994) Fifty years of the MRC Applied Psychology Unit. The Psychologist, 7 (11), 513-514.

Brown, I.D. Batts, V. & McCougan, C.E. (1970). The Medical Research Council Applied Psychology Unit, Occupational Psychology, 44, 267-279

Brown, I.D. Batts, V. & McCougan, C.E. (1971). The Medical Research Council Applied Psychology Unit, Applied Ergonomics, 1, 169-176.

Craik, K. J. W. (1944). Medical Research Council, Unit for Applied Psychology. Nature, 134, 476-477.

Craik, K. J. W. (1945). A new Cambridge unit of research in applied psychology, Occupational Psychology, 19, 15-19.

Reynolds, L.A. & Tansey, E.M. (2003). The MRC Applied Psychology Unit. (Transcript of a Witness Seminar held at the Wellcome Trust Centre for the History of Medicine at UCL, London, 12th June 2001). London: The Trustees of the Wellcome Trust.

Poulton, E.C. (1964). The Medical Research Council’s Applied Psychology Unit.

Cambridge U. Med. Soc. Mag. (Murmur), 10, 3-7.