Individual differences in schizotypy and reduced asymmetry using the chimeric faces task

Recent work in schizophrenia has suggested a reduction in right hemisphere processing in patients experiencing first-rank symptoms. Similarly, work in individual differences in schizotypal personality traits in the normal population has suggested differences in hemispheric processing that may mirror results in diagnosed groups. A reduction of attentional asymmetry to the left visual field was hypothesised in right-handed males scoring highly on measures of positive schizotypy.

Normal adult subjects completed a questionnaire containing five scales of Unusual Experiences, Cognitive Disorganisation, Introvertive Anhedonia, Impulsive Nonconformity, and Schizotypal Personality Disorder. In the first experiment, subjects made emotional decisions to chimeric faces under free viewing conditions. The second experiment was intended to replicate the first but used tachistoscopic presentations as well as counterbalancing subjects with respect to laterality of response keys.

Reduction in attentional asymmetry was correlated with scales of positive schizotypy in both experiments in males only. In addition, the relationship was a dynamic one, developing over time as the attentional asymmetry increased for low schizotypal scorers but did not for high scorers.

Together, these results suggest that there is a reduction of right hemisphere arousal in some individuals possessing a predisposition to experience unusual perceptions that echoes similar findings in acute schizophrenics.