Apophenia, theory of mind and schizotypy: perceiving meaning and intentionality in randomness.

Impaired ability to correctly infer others' mental states ('Theory of Mind' - ToM) and the tendency to perceive meaning in unrelated events ('apophenia') have been implicated in vulnerability to schizophrenia. Sixty-three healthy participants completed three experimental tasks that provided indices of ToM and apophenia. The first task (Contingency) required participants to rate the strength of relationship between the movements of two shapes; in some conditions the movements were unrelated, in others the movement of one shape was contingent on that of the other. In the second task (Stories), participants answered questions on short stories with 'random', 'physical' or 'ToM' themes. The third task (Triangles) required participants to view and then describe the movement of triangles on a computer screen in 'random', 'physical' and 'ToM' conditions. Participants completed questionnaire measures of psychosis-proneness (the Schizotypal Personality Scale - STA) and delusional thinking style (Peters et al. Delusions Inventory - PDI-21). Little evidence was found on any of the tasks for an association between a specific deficit in ToM accuracy and any aspect of psychosis-proneness. On the Triangles task, schizotypal and delusion-prone participants spontaneously reported perceiving a greater number of associations in the random condition (apophenia). On both the Triangles and Contingency tasks, over-mentalizing was found to be associated with delusional thinking but not with general schizotypy. We speculate that over-mentalizing may be underpinned by a hyper-associative cognitive style, linked to an exaggeration of the normal human tendency to attribute mental states, rather than to dysfunction in the assessment of causality. Perceiving meaning in randomness and, more particularly, attributing mental states where none are indicated, may be important factors in the formation of paranormal and delusional beliefs.