Eye-tracking reveals a slowdown of social context processing during intention attribution in patients with schizophrenia

Abstract

Background: Schizophrenia is associated with poor theory of mind (ToM), particularly in the attribution of intentions to others. It is also associated with abnormal gaze behaviours and contextual processing. This study investigated to what extent impaired ToM in patients with schizophrenia is related to abnormal processing of social context.

Methods: We evaluated ToM using a nonverbal intention attribution task based on comic strips depicting social/nonsocial and contextual/noncontextual events while eye movements were recorded. Eye-tracking was used to assess processing time dedicated to visual cues contained in regions of interest identified in a pilot study. We measured cognitive contextual control on a separate task.

Results: We tested 29 patients with schizophrenia and 29 controls. Compared with controls, patients were slower in intention attribution but not in physical reasoning. They looked longer than controls at contextual cues displayed in the first 2 context pictures of the comic strips, and this difference was greater for intention attribution than for physical reasoning. We found no group difference in time spent looking at noncontextual cues. Patients' impairment in contextual control did not explain their increased reaction time and gaze duration on contextual cues during intention attribution.

Limitations: Difficulty may not have been equivalent between intention attribution and physical reasoning conditions.

Conclusion: Overall, schizophrenia was characterized by a delay in intention attribution related to a slowdown of social context processing that was not explained by worse executive contextual control.

Figures

Fig. 1

Example of an item in the intention attribution and in the physical causality conditions of the task. Dotted circles represent the regions of interest.

Fig. 2

Mean error rates for the low and high contextual control conditions. Error bars represent the standard error of the mean.

Fig. 3

Mean (A) error rates and (B) reaction times computed from forced-choice responses. Error bars represent the standard error of the mean.

Fig. 4

Mean (A) contextual and (B) action region of interest looking times. Error bars represent the standard error of the mean.