| Abstract: | Perceptual differences between normals and schizophrenics revealed by traditional size-constancy experiments are questionable because of S variability, procedural difficulties, and problems inherent in traditional psychophysical methods. A review of the literature reveals few consistent results. The present study compared normals, paranoid schizophrenics, and nonparanoid schizophrenics on a size-constancy task which allowed derivation of additional dependent variables from signal-detection and uncertainty analysis. No group differences were revealed using the size-constancy procedure, but signal-detection analysis indicated nonparanoid schizophrenics were significantly lower in perceptual sensitivity. Uncertainty analysis revealed additional response dispositions characteristic of the schizophrenic groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
