ABSTRACT
Lieberman (2013) has explored numerous dimensions of the role of such norms in cognitive psychology, noting work on the ‘neural signature of norm compliance’ (Spitzer, Fischbacher, Herrnberger, Gron, & Fehr, 2007). He reports on one study (Rilling, Sanfey, Aronson, Nystrom, & Cohen, 2004) in which functional magnetic resonance imaging of subjects playing a 2-person Prisoner’s Dilemma game were analyzed. Subjects were paired with other players who chose to cooperate rather than defect or ‘free ride’. More brain activity (in the ventral striatum) occurred in players when, given cooperation by another player j, player i/self also chose to cooperate rather than defect: ‘The ventral stratum seemed to be more sensitive to the total amount earned by both players, rather than to one’s personal outcome. Moreover, the lateral prefrontal regions were not engaged in the study when the subjects cooperated, suggesting that cooperating involves a real preference, not a sense of obligation’ (Lieberman, 2013, p. 85).
