Patients with schizophrenia (SC) show deficits in the processing of social cues. Little is known whether this deficit in social cognition also influences non-social, “cold” cognition. Interactions between these domains can be tested with a Simon task using social stimuli (gaze direction).

We investigated whether the Simon effect, the slowing of reaction times produced by stimulus incongruities in the spatial domain, differs in patients with schizophrenia and healthy controls as a function of the social nature of the cues. Participants: Thirty-five recent-onset, male SC and 30 male HC participated in the study.

We used the gaze-direction Simon effect paradigm described by Zorzi et al.[1], in which the Simon effect is generated by a schematic drawing of human eyes (social cues) or rectangles (non-social cues).

Overall SC had longer reaction times. Furthermore, groups showed a Simon effect in both tasks. While in HC the Simon effect was stronger in the eye-like compared to the rectangle condition, for SC the Simon effect was less strong in the eye-like compared to the rectangle condition. Current psychopathology or treatment with antipsychotics did not influence results.

Although the Simon effect is present in SC, the influence of social cues was much reduced in the patient group.

The present study supports earlier findings of altered processing of social cues in SC. Crucially; we demonstrated that this deficit in social cueing affects early attentional processes in schizophrenia.