Reduced self-referential neural response during intergroup competition predicts competitor harm

Abstract

Why do interactions become more hostile when social relations shift from "me versus you" to "us versus them"? One possibility is that acting with a group can reduce spontaneous self-referential processing in the moral domain and, in turn, facilitate competitor harm. We tested this hypothesis in an fMRI experiment in which (i) participants performed a competitive task once alone and once with a group; (ii) spontaneous self-referential processing during competition was indexed unobtrusively by activation in an independently localized region of the medial prefrontal cortex (mPFC) associated with self-reference; and (iii) we assessed participants' willingness to harm competitors versus teammates. As predicted, participants who showed reduced mPFC activation in response to descriptions of their own moral behaviors while competing in a group were more willing to harm competitors. These results suggest that intergroup competition (above and beyond inter-personal competition) can reduce self-referential processing of moral information, enabling harmful behaviors towards members of a competitive group.

Keywords: Intergroup competition; Medial prefrontal cortex; Self; Social cognition; fMRI.

Fig. 1

A) A schematic overview of the procedure. B) Examples of stimuli from the main experiment. C) Example of the picture-rating task for one target (independent pre-test rankings appear beneath each photo: 1 = most flattering to 6 = least flattering; participants in the current study did not see the rankings).

Fig. 2

Left panel: Group mPFC ROI, based on self>other contrast in the localizer experiment (peak: −4, 34, −4, k = 377). Top right panel: correlation between spontaneous mPFC response to self>other moral behavior and willingness to harm competitors when competing alone, r(19) = .09, p = ns. Bottom panel: significant negative correlation between spontaneous mPFC response to self>other moral behavior and willingness to harm competitors when competing with the group, r(19) = −.44, p < .05.