Disruption on right temporoparietal junction with transcranial magnetic stimulation affects moral judgment: No difference between first- and third-personal narration with TMS.

Brain imaging studies have observed that the right temporoparietal junction (rTPJ) was involved in the information processing of moral judgments and in the understanding of the beliefs/intentions of other people. However, most of these studies used moral stories in the third-person point of view. This study aimed to investigate to what extent the disruption of rTPJ affected moral judgments with stories in first-person narration by non-invasive transcranial magnetic stimulation (TMS). The study hypothesized that, first, TMS would disrupt moral judgment, causing one to neglect the beliefs of perpetrators and to make judgments based on eventual harmful outcomes. Thus, the experimental group would be more tolerant towards "intentional harm" and more prohibitive towards "accidental harm" in comparison to sham. Secondly, TMS might disrupt the mechanism to change perspectives - TMS would influence the moral judgment of the stories narrated in third person (perspective of others), but not those narrated in first person (perspective of oneself). The results demonstrated that (1) TMS accelerated moral judgment (Experiment 1), which might be due to the practice effect from the order of TMS application (Experiment 2); (2) TMS affected moral judgment in several conditions. Participants adopted a more prohibitive attitude towards conditions of "intentional harm", as well as "accidental harm" with TMS disruption; (3) The effect of personal perspective was marginally significant, revealing a tendency "to be stringent with oneself and tolerant towards others". However, the interaction between personal perspectives and TMS was insignificant. No difference between the first- and third-person perspectives was found with TMS disruption.