Modulating the Activity of the Right Dorsolateral Prefrontal Cortex Alters Altruism in Situations of Advantageous Inequity.

Altruism is highly valued and cherished by human society. However, human preferences and behavior are sensitive to inequality considerations. Currently, remarkably little is known about the neurobiological mechanisms underlying the process of altruistic acts in inequity situations. Therefore, to clarify the causal role of the right dorsolateral prefrontal cortex (rDLPFC) in altruism during situations of advantageous and disadvantageous inequity, we applied transcranial direct current stimulation (tDCS) to demonstrate the involvement of the rDLPFC in altruism in situations of inequity. A total of 71 participants (38 female and 33 male) received anodal tDCS at 1.5 mA over the rDLPFC (n = 38) or the primary visual cortex (n = 33) and subsequently participated in a modified dictator game that measures altruism. We found that anodal tDCS over the rDLPFC decreased subjects' sensitivity to altruistic efficiency and cost in situations of advantageous inequity. Our results suggested that the rDLPFC plays an important role in overriding self-interest to enforce altruism in situations of advantageous inequity.