Judgments About Others’ Trustworthiness: An fMRI Study

Abstract

We investigated how information about others’ trustworthiness affects brain region activation in a functional MRI (fMRI) study. Participants were given statements about a person’s behaviors and were asked to judge whether or not the person was trustworthy while undergoing fMRI imaging. Participants read 32 statements, half of which were relevant to making judgments about trustworthiness, and half of which were irrelevant to making judgments about trustworthiness. We found that making trustworthiness judgments when reading relevant statements was associated with differential activation in five regions: the angular gyrus (AG), anterior cingulate (AC), left frontal lobe (LF), right frontal lobe (RF), and putamen/caudate nucleus (PU/CA). Previous studies using highly abstract economic game situations have also shown activation in these regions. These regions are also related to the learning process and to theory-of-mind processing. In addition, we found that people with high or low scores on a general trust scale showed less activation than did people with middle-range scores. These results suggest that we use trial-and-error learning to decide whether to trust others, and that this learning history (represented here as general trust level) influences automatic processing of new trust judgments.