Reducing prejudice through brain stimulation

Abstract

Background Social categorization and group identification are essential ingredients for maintaining a positive self-image that often lead to negative, implicit stereotypes toward members of an out-group. The medial prefrontal cortex (mPFC) may be a critical component in counteracting stereotypes activation. Objective Here, we assessed the causal role of the mPFC in these processes by non-invasive brain stimulation via transcranial direct current stimulation (tDCS). Method Participants (n = 60) were randomly and equally assigned to receive anodal, cathodal, or sham stimulation over the mPFC while performing an Implicit Association Test (IAT): They were instructed to categorize in-group and out-group names and positive and negative attributes. Results Anodal excitability-enhancing stimulation decreased implicit biased attitudes toward out-group members compared to excitability-diminishing cathodal and sham stimulation. Conclusions These results provide evidence for a critical role of the mPFC in counteracting stereotypes activation. Furthermore, our results are consistent with previous findings showing that increasing cognitive control may overcome negative bias toward members of social out-groups.