Schizotypy and pseudoneglect: a critical update on theories of hemispheric asymmetries

Positive schizotypy has been associated with a leftward spatial bias (pseudoneglect) in different tasks and populations. We tested whether this relationship (1) can be observed for two different hemispatial tasks in the same participants, and (2) is specific to positive schizotypy.

Forty right-handed men performed a conventional line bisection task and a whole-body movement task. In the latter task, participants were presented with illuminated target locations on the floor, and had to visit the remembered locations (equal number in right and left hemispace) after a short time interval. We assessed side preferences in both tasks. Positive schizotypy, negative schizotypy, and cognitive disorganisation were assessed with a validated self-report questionnaire.

Irrespective of schizotypy, pseudoneglect was observed in both tasks. We found a rightward bisection and walking bias as a function of positive schizotypy, and also as a function of cognitive disorganisation for walking initiation.

This unexpected finding resulted in a review of hemispheric asymmetry for function in schizotypy, and in the discussion of potential variables that might account for the present discrepancy. We suggest that different schizotypy questionnaires and their presentation mode might be a potential contributor to the opposite findings in the literature.