Fig. 3.

Neural responses associated with prosocial behavior and witnessing in-group and out-group members win money. (A) During decisions to allocate money to the self or another person, medial orbitofrontal cortex (mOFC) showed increasing activation when participants allocated money to whomever stood to gain more (i.e. efficient choices), shown in yellow. Anterior cingulate cortex (ACC) showed increasing activation when participants allocated money inefficiently—for example, keeping money for the self when another person could gain more. (B) A portion of ventral striatum associated with the term ‘reward’ in an automated meta-analysis using Neurosynth. (C) Within this portion of ventral striatum, group-level self-investment predicted differential parametric responses to increasing amounts of money won by in-group members versus out-group members. The y-axis shows predicted parameter estimates (from a regression analysis) representing the strength of relationship between ventral striatum response and amount won by in-group or out-group members. Predictions for high and low self-investment are plotted one standard deviation above and below the mean.