tDCS of Medial Prefrontal Cortex Does Not Enhance Interpersonal Trust

Interpersonal trust is an essential ingredient of many social relationships. Previous research has suggested that the medial Prefrontal Cortex (mPFC) may be a critical component in mediating the degree to which people trust others. Here we assessed the role of the mPFC in modulating interpersonal trust by means of transcranial direct current stimulation (tDCS). Participants (n = 60) were randomly and equally assigned to receive anodal, cathodal, or sham stimulation while performing the Trust Game, an index of interpersonal trust that assesses the money units one participant (the trustor) transfers to another (the trustee). Results showed that neither anodal stimulation (brain stimulation that increases cortical excitability of the area being stimulated) nor cathodal stimulation (brain stimulation that decreases cortical excitability) affected the degree of interpersonal trust as compared to sham stimulation. We conclude that noninvasive electrical stimulation over the mPFC does not modulate the degree to which people trust others.