Ultimatum bargaining behavior of people affected by schizophrenia.

Forty-nine people suffering from schizophrenia performed an interactive bargaining task involving small monetary rewards, known in classical game theory as the Ultimatum Game. In this task, the subject, in the role of the Proposer, has to offer his or her (anonymous) counterpart, the Responder, a share of a given sum of money. If the Responder accepts the offer, then the sum is split accordingly between the two. Otherwise, if he or she decides to reject the offer, both receive nothing. The patients' strategic behavior in both roles was compared with that of healthy and clinical controls. It was hypothesized that cognitive deficits characterizing schizophrenia, together with difficulties in social judgment, would impair the patients' bargaining ability. We found that in general schizophrenic patients did not fully exploit their strategic power as Proposers. In contrast, as Responders, schizophrenic patients acted not significantly different from controls. Further investigation is needed to establish the links between cognitive and symptomatic mediators and strategic decision-making ability.