Reduced cognitive inhibition in schizotypy

The relationship between negative priming and the positive symptoms of schizotypy was investigated. It was hypothesized that high schizotypes would display less negative priming than low schizotypes. A further important aim of the study was to disentangle the modalities involved in negative priming performance, since a reduction in negative priming, as revealed by schizophrenics and schizotypes, might reflect a failure to actively inhibit irrelevant information (cognitive inhibition) as well as dyslexia or a general slowness in information processing.

A paper test based on the German version of the Stroop test was used to measure negative priming. A baseline condition of the test, colour word reading, that has proven to be a valid indicator of dyslexia was used to measure the influence of reading disturbances on negative priming. Additionally, a priming condition, termed inverted priming, in which the target of a stimulus is identical with the distractor in the subsequent stimulus, was employed.

Fifty healthy adults were drawn from the general population. After neuropsychological assessment participants completed a battery of schizotypal questionnaires. Correlational analyses and mean comparisons were used to investigate the relationship between neuropsychological data and schizotypy.

Results suggest that reduced negative priming is related to positive schizotypy. Reduced negative priming in high schizotypes was unrelated to dyslexia, and found unlikely to be affected by deficits in early processing. The inverted priming condition produced comparatively fewer errors in high schizotypes.

Results support the hypothesis that reduced cognitive inhibition may underlie positive schizotypal symptomatology.