The ability to infer the mental states of others, that is, ‘menatlizing’ has been the focus of much recent research. Autistic humans are hypothesized to lack this ability, and as a consequence are unable to engage in normal social discourse. This paper reports a functional neuroimaging study using fMRI in which we studied brain activity in normal subjects while they performed joint decision-making tasks (extensive form games) with a subject outside the scanner. The resultant brain activity was compared with that measured in a control task: joint decision making with the computer following a fixed probabilistic strategy. Comparison of the decision making with another human to that of playing the computer revealed a specific pattern of activation in the orbitofrontal cortex, left medial frontal gyrus (Broadmann’s area 8), and the posterior cingulate. These are the same areas where recent studies have found activations associated with mental state attribution in individual choice settings. The localization of brain regions involved in normal attribution of mental states is feasible within the context of two-person decision-making and may have implications for understanding how normal persons infer the strategic behavior of others.

Co-authors Georgio Coricelli, Daniel Houser, Lee Ryan, Vernon Smith, Theodore Trouard