Are patients with schizophrenia rational maximizers? Evidence from an ultimatum game study

Schizophrenia is associated with impaired social cognition and community functioning. Social decision-making strategies of healthy controls and patients with schizophrenia were compared by using the ultimatum game (UG). In this game two players have to split a sum of money. The proposer offers a portion to the responder, who decides to either accept or reject the offer. Rejection results in no income to either of the parties. Unfair proposals are frequently rejected by nonclinical individuals, a phenomenon described as altruistic punishment. Patients and controls participated in a series of UG interactions as responders in a computerized test setting. We also tested the effect of the proposer's facial expression on decision-making. Our results indicate that patients with schizophrenia accepted unfair offers at a significantly higher rate than did healthy controls. In contrast, at fair proposals, the acceptance rate was lower in patients compared with controls. At higher offers, the proposer's facial expression (positive/negative) significantly influenced the acceptance rate (positive facial expression increased the likelihood of acceptance) in the control group. This effect was not observed in the patient group. These results suggest that schizophrenia patients are impaired in socioeconomic interactions requiring emotion recognition and decision-making, which may result in unstable behavioral strategies.