Abstract
Introduction: Schizophrenia and schizotypy (a genetic predisposition to schizophrenia without the environmental factors leading to schizophrenia) can cause disruptions in basic attentional tasks (e. g.: cueing, Posner, et al., 1988; visual search, Alain, Bernstein, et al., 2002). It has been suggested that schizophrenia and schizotypy are not discrete disorders, but fall along a spectrum or continuum that includes non-schizophrenic/non-schizotypal populations (Baron & Risch, 1987; Johns & van Os, 2001). We assessed this suggestion by comparing non-schizotypal participants' performance on visual search with scores on a standard schizotypy questionnaire (Schizotypal Personality Questionnaire-B, Raine & Benishay, 1995).
Method: 43 participants completed the SPQ-B questionnaire and a series of yes/no feature and conjunction visual searches of spatial frequency and orientation. The target for all conditions was a high-contrast (46.7%) vertical Gabor (1 cpd, 1-octave bandwidth, full-width half-height). The orientation distractor Gabors differed in orientation (10°), and the spatial frequency distractor Gabors differed in spatial frequency (1.3 cpd, 0.757-octave bandwidth, full-width half-height). Searches were defined by presenting either one (feature) or both types (conjunction) of distractors. The total number of items (set size) was 2, 4, or 6; stimuli were presented for 250 ms at 10° eccentricity, with 100 trials/condition.
Results: Non-schizotypal participants‘ results were compared to their overall and three subscale scores (Cognitive/Perceptual, Interpersonal, Disorganized) of the SPQ-B. A median split of scores found that percent correct for orientation was lower for high (more indicative of schizotypy) Cognitive/Perceptual scorers (F(2, 41)=3.323, pr=−.366, pr=−.354, pr=−.341, p[[lt]].05)). These results suggest that disruptions of basic attentional processing associated with schizophrenia/ schizotypy may comprise a continuum extending into populations having no diagnoses for the disorders.