Temporal processing and psychosis proneness

Abstract

Two measures of temporal processing: critical stimulus duration (CSD) and visual backward masking (VBM), were examined in a group of normal subjects whose predisposition to psychosis was assessed using the psychoticism (P) scale from Eysenck's Personality Questionnaire. The current study employed the method of constant stimuli with a two-alternative forced choice responding to reduce the variability in CSD-data. Higher P scorers required a significant longer target stimulus duration in order to correctly identify the stimulus than lower P scorers. These results suggest that subjects prone to psychosis possess a relatively less sensitive temporal processing system than low P scorers. Performance in the subsequent masking phase revealed no evidence of a VBM deficit. It was not possible to explain this pattern of results in terms of task difficulty. The findings were discussed in terms of potential inadequacies in previous calculations of CSD. This possibility requires further testing before the backward masking deficit can be adopted as a trait marker for schizophrenia.