Moral reasoning in schizophrenia: an explorative study into economic decision making

Abstract

Introduction: Previous research has suggested that patients with schizophrenia are impaired in appreciating moral values and social norms. Here, we tested the hypothesis--using economic games--that patients with schizophrenia are similar to normals in their ability to recognise unfairness, but perhaps more tolerant towards the acceptance of unfair offers depending on the severity of negative symptoms.

Methods: Twenty-five patients with schizophrenia played an Ultimatum Game and a Dictator Game with punishment option to examine their ability to appreciate fairness rules and to reinforce equity in comparison to a healthy control group.

Results: As hypothesised, patients accepted significantly more unfair offers than controls. However, rejection rates increased in relation to the unfairness of proposals in both groups. Patients did not differ significantly from controls in the likelihood of punishing unfairness in the Dictator Game or in punishment investment itself.

Conclusions: Patients with schizophrenia seem to be less sensitive towards unfairness to their own disadvantage, but punish unfairness at a comparable level to controls, which opposes the common view of a general lack of moral value appreciation in schizophrenia.

Keywords: Costly punishment; Game theory; Moral values; Schizophrenia; Social norms.