Effects of stimulus structure and target-distracter similarity on the development of visual memory representations in schizophrenia.
BACKGROUND
In a previous study (Silverstein, Bakshi, Chapman, & Nowlis, 1998a, Cognitive Neuropsychiatry) we demonstrated that while schizophrenia patients showed similar learning curves as nonpatient controls when determining whether a configural pattern of elements has been seen before or not, they did not demonstrate any learning curve with nonconfigural stimuli (in contrast to controls). Methodological limitations of that study, however, precluded generalisability of those effects.


METHODS
In the present study, therefore, different groups of schizophrenia patients (n = 18) and controls (n = 22) were administered a modified version of the familiarity judgement task used in Silverstein et al. (1998a). In the new version of the task: (1) the patterns that repeated were different for each participant; and (2) half of the nonrepeating patterns were configural and half were nonconfigural.


RESULTS
These indicated stronger perceptual learning effects for the configural compared to the nonconfigural patterns, and overall better performance and more pronounced learning effects for the control group.


CONCLUSIONS
The data provide further evidence for a schizophrenia-related impairment in perceptual organisation and in the ability to develop memory representations for novel stimuli.
Silverstein
Steven M
SM
Center for Cognitive Medicine, Department of Psychiatry, University of Illinois at Chicago, 60612, USA. ssilverstein@psych.uic.edu
Bakshi
Shabnam
S
Nuernberger
Scott
S
Carpinello
Kelly
K
Wilkniss
Sandra
S