Latent inhibition, learned irrelevance, and schizotypy: assessing their relationship

Previous research suggests that latent inhibition is reduced in patients with acute schizophrenia and in healthy participants with high levels of schizotypic characteristics. Other evidence indicates the disruption of a related effect (learned irrelevance) in patients with acute schizophrenia.

This study used a recently developed latent inhibition procedure, that avoids methodological limitations of previous studies, and a related learned irrelevance procedure to assess the relationship between these phenomena and schizotypic characteristics in undergraduate participants.

Participants preexposed to a letter (S) learnt the predictive relationship between that letter and another letter (X) slower than the relationship between a novel letter and X (a latent inhibition effect). Experiment 1 found reduced latent inhibition in the high schizotypy group after 10, but not 20 preexposures. In Experiment 2, participants preexposed to both S and X learnt a subsequent relationship between them slower than the relationship between a novel letter and X (a learned irrelevance effect). This effect was abolished in participants with high levels of schizotypy.

These results are both the first demonstration of abolished learned irrelevance and of a significant reduction in latent inhibition without employing an explicit masking task in participants with high levels of positive schizotypy.