Reduced visual scanpath is associated with inferential reasoning task in schizophrenia

Changes in oculomotor behavior are recognized features of schizophrenia, and eye movements are related to cognitive processing. However, little is known about how visual scanning is associated with cognitive biases during contextual reasoning. This study investigated associations between oculomotor patterns and the integration of disconfirmatory evidence in schizophrenia.

Cross-sectional study, comprising 25 male individuals diagnosed with schizophrenia and 25 healthy controls. The Bias Against Disconfirmatory Evidence (BADE) Task, an inferential reasoning task based on new visual information and plausibility ratings of interpretative statements, was performed during eye-tracking recording. A mediation model assessed whether scanpath length mediated the relationship between schizophrenia diagnosis and biases in the integration of disconfirmatory evidence.

Individuals with schizophrenia showed lower number of eye fixations (t = 2.990, p = 0.004, d = 0.847), shorter visual scanpath (z = -2.702, p = 0.007), and higher BADE score (z = -3.095, p = 0.002, d = 0.437) than controls. The mediation model indicated that shorter scanpath length had a significant indirect effect, thus linking schizophrenia diagnosis to higher BADE scores (B = 2.71, 95% CI = 0.13-8.68). In sensitivity analyses, this association was no longer significant after controlling for estimated IQ, and the total indirect effect was primarily explained by the pathway through IQ.

Reduced visual scanning in schizophrenia was associated with greater difficulty integrating disconfirmatory evidence during contextual reasoning. However, its association with BADE performance cannot be considered independent of general cognitive ability. Future studies should confirm these results, examine the effects of experimental variations, and explore the underlying cognitive and pathophysiological mechanisms.