Mesencephalic dopamine neurons are believed to facilitate reward-dependent learning by computing errors in reward predictions. We used fMRI to test whether this system was activated as expected in response to errors in predictions about whether a social partner would reciprocate an act of altruism. Nineteen subjects received fMRI scans as they played a series of single-shot Prisoner's Dilemma games with partners who were outside the scanner. In both ventromedial prefrontal cortex and ventral striatum, reciprocated and unreciprocated cooperation were associated with positive and negative BOLD responses, respectively. Our results are consistent with the hypothesis that mesencephalic dopamine projection sites carry information about errors in reward prediction that allow us to learn who can and cannot be trusted to reciprocate favors.
1Center for the Study of Brain, Mind and Behavior
2Department of Psychology
3Center for Health and Well-Being, Princeton University, Princeton, NJ 08544
4Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
5Present Address: Department of Anthropology, 1557 Pierce Drive, Geosciences Building, Emory University, Atlanta, GA 30322, USA
CACorresponding Author: email@example.com
Received 31 July 2004; accepted 31 August 2004