CBSU bibliography search
To request a reprint of a CBSU publication, please click here to send us an email (reprints may not be available for all publications)
When recognition is dominated by regularity: The effects of semantic impairment on perceptual decisions.
ROGERS, T. T., Lambon Ralph, M.A, HODGES, J.R, and PATTERSON, K
In: Cognitive Neuroscience Society Annual Meeting Program 2002.
Year of publication:
Although patients with semantic deficits can sometimes show fairly good performance on tests of object decision, we present evidence that this pattern applies when nonsense-object stimuli do not respect the regularities of the domain. Eighteen patients with semantic dementia viewed pairs of line drawings, with a real and a chimeric animal side-by-side, and were asked to decide which was real. The chimera was either more prototypical (over-regular condition) or less prototypical (irregular condition) than the real animal. Performance in both conditions was modulated by the extent of the patients' semantic impairment; but regardless of severity, patients were less successful in the over-regular than the irregular condition. The most severe patients were no better than chance on over-regular stimuli,but above 80% correct on irregular stimuli. The results are consistent with a recurrent distributed model of conceptual knowledge, in which structured semantic representations emerge from the interaction of high-level perceptual representations.