Abstract
The threat of punishment is a central concept in theories of social interaction, cognitive control, economic behavior, and crime prevention. We used event related functional magnetic resonance imaging (fMRI) in conjunction with a version of the dictator's game in order to study the neural substrate of thinking about the consequences of possible future punishment. In line with previous studies (Fehr & Gächter 2002), behavioral data indicate that subjects invested significantly more monetary units in a version of the ultimatum game when they knew that they could be punished for “free riding”. During the phase of investing under the threat of future punishment, we found a significant activation of the left middle frontal gyrus and the head of the caudate nucleus bilaterally. Both middle frontal and right caudate activity were highly positively correlated with the increased amount invested, predicting 46% and 26% of the variance, respectively.
The results are in line with known frontal lobe involvement in planning and control, as well as known frontal structural and functional pathology in psychopaths and criminal offenders. They provide the economic approach to punishment with an external measure of cognitive functions involved in rational choice.