Investigating word associations in a schizotypy sample: contrasting implicit and explicit processing

Schizotypy is a useful schizophrenia analogue that controls for confounding factors such as medication and general intellectual decline. In the current study this analogue approach was used to examine implicit/explicit and direct/indirect semantic memory function. This is the first study to examine both implicit and explicit semantic access in the same schizotypy sample.

Participants completed four semantic tasks: (1) implicit indirect priming, (2) implicit direct priming, (3) explicit object (indirect) task, and (4) explicit association (direct) task. The schizophrenia literature suggests that semantic impairments are associated with thought disorder. As such, participants were divided into low (n=18) and high (n=18) schizotypy groups based on their responses to a thought disorder subscale of the Oxford Liverpool Inventory of Feelings and Experiences (O-Life) scale.

In terms of implicit performance, the high schizotypy group demonstrated increased direct priming but nonsignificant indirect priming. The low schizotypy group demonstrated no significant difference in direct and indirect priming. Performance on the explicit tasks was equivalent between the two groups for direct stimuli. On the indirect explicit task, high schizotypy was associated with an increase in errors.

Increased direct priming in high schizotypy is equivalent to that seen in schizophrenia, which has been interpreted as increased spreading of activation. Abnormal performance using the indirect stimuli was found across implicit and explicit versions. The relevance of these findings to schizophrenia are discussed.