Why is magical ideation related to leftward deviation on an implicit line bisection task?

Right hemispatial inattention is a neurocognitive deficit observed in thought-disordered schizophrenia patients, persons with schizotypal personality disorder and healthy participants with high scores on schizotypy scales. We administered a schizotypy inventory, the Magical Ideation (MI) scale, to forty healthy, right-handed men who had copied and later recalled the Rey-Osterrieth complex figure. Implicit line bisection performances were defined as the bisecting lines of the complex figure's large rectangle and were recorded for the copy and delay conditions. MI scores were significantly correlated with a leftward shift in bisections in the delay but not copy condition, indicating a significant relationship between the degree of right hemispatial inattention and number of magical beliefs in healthy participants. We describe a model in which these beliefs are conceptualized as a consequence of a hemispheric imbalance, specifically, of a right hemisphere processing bias. This model accounts for (1) the leftward shifts in spatial attention and (2) the language deficits associated with psychosis and related symptom clusters which have hitherto been addressed in separate literatures. Clinically, the Rey-Osterrieth test may provide a means to assess implicit hemispatial inattention in psychotic patients.