Negative priming in schizophrenia: effects of masking and prime presentation time

Beech ee al. [Br. J. Clin. Psychol. 28 (1989) 109-116] previously reported attenuated negative priming in schizophrenic patients that was interpreted as a sign of dysfunctional cognitive inhibition. However, subsequent resear ch has provided mixed results. In the present study, it was investigated wh ether reduced negative priming in schizophrenics may be an experimental art ifact. Based on evidence from backward masking studies in schizophrenia, it was hypothesized that brief prime presentation times and pattern masking a s used by Beech et al. and others may have impaired the visual perception o f the prime display in schizophrenics. 20 schizophrenic patients and 20 mat ched healthy controls participated in the study. Subjects completed four ne gative priming experiments varying in prime presentation time (100 or 250 m s) and masking (a mask or a blank screen followed prime presentation). In L ine with prediction, reduced negative priming in schizophrenics only occurr ed for trials with 100 ms prime presentation time followed by a mask. Neith er psychopathology nor any sociodemographic variable correlated substantial ly with negative priming. Results strongly suggest that reduced negative pr iming in schizophrenics may not be due to reduced cognitive inhibition but mirrors perceptual deficits. (C) 2001 Elsevier Science B.V. All rights rese rved.