Neural basis of carry-over effect during intertemporal choice: Preliminary results of an fMRI study

Background: Previous anthropological studies suggested that altruistic punishment is important for sustaining cooperation in large groups. In the clinical literature, major depressive disorder (MDD) has been associated with guilt driven pathological altruism. However, previous neuroeconomical studies suggested that altruism in MDD does not include forms of altruistic punishment. Methods: We used script based Dictator and Ultimatum Game (DG and UG) paradigms to test proposing and altruistic punishment behaviour in 33 healthy subjects, 24 patients with current MDD and 35 patients with remitted MDD. Following UG decision‐making, participants rated the emotional valence of the offers they received and selected a single emotion from an open‐ended list of positive and negative emotions. Results: We showed that patients did not differ from healthy subjects, whether they were proposing or responding to offers. Furthermore, our groups were not different in terms of their pleasantness/unpleasantness ratings for fair and unfair offers. However, we showed that patients with current MDD experience significantly more guilt, relative to shame or indignation, upon receiving unfair offers in the UG (F (2, 89) = 3.582, p = .032). Conclusion: Altruistic punishment behaviour requires blaming other individuals for their moral/behavioural violations. Our results suggest that abnormally elevated self blame (guilt) in MDD is important for understanding lack of altruistic punishment behaviour in depressed patients. 5