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9. PSYCHOPHYSIOLOGY SECTION PROJECTS
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9.1 Portable Apparatus for Assessing Deterioration of Skill (Houghton, Wilkinson)(Project No.14)
The main goal of this research is the development of a battery of five small, highly portable devices for assessing various aspects of performance. Tvo of them. Four Choice Serial Reaction Time and Simple Reaction Time, are complete and available from the manufacturer (200). There are two tests, one of Short Term Memory and one of Vigilance, in prototype form and being tested operationally. The fifth test, Tracking, is in the design stage.
9.2 Performance After Reduced Amounts of Sleep (Glenville, Herbert, Wilkinson)(Project No. 15)
During 1975 and early 1976 Herbert has analysed and reported on data acquired previously to produce five papers on various aspects of the quality of sleep in relation to performance (63; 65; 67), mood (62), and subjective reports (66). He also administered a questionnaire to some 352 people in the Cambridge area to obtain details of their habits of sleep and also of other features of their life and environment to which the quality of their sleep might be related. The general aims of this project are, first, to enquire into such relationships and, second, to form the basis of a pool of poor sleepers who might be invited to take part in future experi¬ments.
Glenville (5t) assessed the performance of the staff of International Computers Limited, on the portable tasks of Project 14, studied over a period -jf weeks, at various times of the day and night. The main purpose of the study was to assess the effect of loss of sleep on people when they transfer from the day tj the night shift. Reliable individual differences in susceptibility to loss of sleep were observed, suggesting, that it may be possible to select people Cot night shift work.
Further evidence for individual differences in the effect of one nights loss of sleep were obtained in a study of performance in the laboratory (521. Data from a second larger scale study have been collected and are being analysed.
While on detachment at. the Navy Medical Neuropsychiatric Research Unit, San Diego, California, Wilkinson (with Mullaney) examined the feasibility of using the Modi lug Miniature Portable Sattery Tape Recorder, with an appropriate preamplifier, to record sleeping and waking EEG activir.y in the home. The record of EEG from the Medilog was shown to compare well with that take.i: simultaneously by normal methods from the same, electrode. The sleeping EFT- was recorded successfully at home, but the waking EEG was often obscured by movement artifacts (201).
9.3 Effects of Single or Combined Stresses (Adams, Herbert, Millar,Tyler, Varey, Wilkinson) (Project No. 16)
A series of experiments has been completed in which the Psychophysiology Section, APU, has combined with outside establishments who have facilities for administering particular kinds of stress, the unit's contribution being that of expertise in measuring performance. These experiments, with references to published reports, are summarised briefly as follows:
(a) With British Medical Association: Duty Hours of Young Hospital Doctors. Effects on the Quality of Work
The results of a questionnaire sent to 6,500 young hospital doctors in Britain were collated, analysed, and published. The main questions were, first, to discover how many felt their hours of duty were so long as to affect their working efficiency and, secondly, to define those specialities and kinds of hospitals in which working efficiency appears most threatened by long hours (202).
(b) With Wellcome Research Laboratories: Residual Effects of Hypnotic Drugs upon Performance.
The main question was whether taking sleeping pills at night improved performance the next day due to better sleep, or impaired it, due to the residual effect of the drug. No overall effect was observed but the results suggested that good sleepers might be impaired and poor sleepers improved by the procedure (155). Also: The Effects of Low Doses of Amylobarbitone Sodium and Diazepam on Human Performance. Clinical and subclinical doses of these drugs were shown to impair performance, particularly prolonged vigilance (59).
(c) With British Airways Medical Service: Effects of Time Zone Changes on Performance and Physiology of Airline Personnel.
Female airline personnel spent A full days living as a group in an isolated apartment. Some were subjected to two 8-hour retardations in time, representing, approximately, a westerly flight from the Far East via USA to UK. During this period performance was impaired due to time zone changes. A therapeutic agent (mepitrazole hydrochloride) failed to alleviate the effects (181).
(d) With British Gas Corporation, R&D Division: Environmental Temperature at the Work Place: Effects on Comfort and Performance.
Employees of BGC Headquarters assessed their comfort as regards environmental temperature and carried out 1-minute performance tests (Portable Simple Reaction Time test) every hour for two working weeks. Results indicated wide individual differences in the degree to which temperatures, both higher and lower than normal, affected performance and comfort (198).
(e) With Middlesex Hospital: Effects of Anaesthetics for Minor Surgery upon Subsequent Performance.
Following minor surgery and the administration of anaesthetics in the morning, performance of patients on the Portable Four Choice Reaction Time test was below normal in the afternoon and evening. Patients should not be released to drive, walk home etc. too soon. A report is in preparation.
(f) With Charing Cross Hospital: Assessment of Hypertensive Patients using Performance Tests.
The Portable Four Choice Reaction Time test is being used to provide objective indications of hypertensive symptoms, and of the possibility of differentiating hypertensive personalities. The experiment is still in progress.
(g) With Birkbeck College, London: Effects of Fatigue on Marine Pilots.
The Simple and the Four Choice Reaction Time tests have been used to assess the performance of marine pilots before, during, and after bringing ships into port. Data have been collected and are being analysed.
(h) A laboratory study showing adverse effects of noise upon short-term memory r.as been completed by Millar (117), and a review chapter has been written by Herbert surveying the effects of environmental factors on performance (64).
9.4 Physiological Correlates of Performance under Stress (Wilkinson) (Project No. 17)
No in-house work has been carried out on this project due to restricted accommodation and also the time required to bring a new computer into full operation. Two experiments have been conducted by Wilkinson while on short visits to laboratories overseas, both were theoretically oriented and concerned with the relationship between the level of performance and concurrent changes in the electroencephalogram (EEG). Besides seeking to discover general laws relating to the way in which the brain functions, this research seeks methods by which states of human alertness can be monitored from an analysis of EEG records.
The first experiment was carried out at the Navy Medical Neuropsychiatric Research Unit, San Diego, California, and related performance on a 40-minute test of signal detection to evoked potential and slow potential changes in the EEG during the task. A paper is about to be submitted for publication.
The second experiment was carried out at the Department of Psychology, University of Illinois, USA and repeated the previous study but with EEG recorded from more locations on the scalp and with improvements in technique designed to answer some questions raided by the first study in San Diego. The experiuectal work has been completed and the data are being analysed.
A review has been published (196) which summarises earlier contributions from this laboratory on the relationships between event related potentials in the EEG and performance. It discusses the implications of these and other contributions to the literature, in assessing the aetiology of a later positive wave of the evoked potential (P300) which appears to vary in amplitude with such behavioural phenomena as selective attention, expectancy, and response confidence.
9.5 Effects of Noise on Sleep (Campbell, Macmorland, R. Patterson, Roberts, Styles, Wilkinson)(Project No. 20)
This study was initiated in August 1977 and forms part of a multinational project partly supported by the Commission of the European Communities to examine the effects of traffic noise upon the sleep of people in their own homes. The aim is to make physiological recordings, particularly the electroencephalogram (EEG), during a night of sleep at home, to administer questionnaires the next morning to learn the person's own opinion of the quality of the previous night's sleep, and to administer performance tests also during the morning of the next day in order to assess behavioural efficiency. All three of these measures might be expected to vary as a function of the quality of sleep and one of the main questions of the study is how far they agree with each other and how far one or more of them can be taken as a reliable objective index of the quality of sleep. In terms of the traffic noise the aim of the experiment is to determine what kinds of noises are most damaging to people's sleep and, in a more general way what levels of traffic noise should be permitted. If individuals differ considerably in the degree to which their sleep can be disturbed by noise, a further aim is to determine the characteristics of those individuals whose sleep is most at risk. In particular, age is a parameter to be studied in this regard.
A satisfactory method of carrying out physiological recordings in the home has been developed. Four channels of physiological information, one channel of behavioural response (a button press whenever awake at night), and the noise level in dB(A) are amplified, where necessary, multiplexed, and transmitted through a radio link to a receiver and tape recorder elsewhere in the house. This is done by a small (70 x 70 x 23mm) module attached to the top of the person's head throughout the night. The analogue noise record is taken in parallel on the tape recorder.
So far, 4 people have been tested for 16 nights each. These trials have in general demonstrated the feasibility of the whole procedure and, in particular, shown that the method of recording causes minimal inconvenience and disturbance for the sleeper.