Neuroanatomy of intergroup bias: A white matter microstructure study of individual differences.
Intergroup bias-the tendency to behave more positively toward an ingroup member than an outgroup member-is a powerful social force, for good and ill. Although it is widely demonstrated, intergroup bias is not universal, as it is characterized by significant individual differences. Recently, attention has begun to turn to whether neuroanatomy might explain these individual differences in intergroup bias. However, no research to date has examined whether white matter microstructure could help determine differences in behavior toward ingroup and outgroup members. In the current research, we examine intergroup bias with the third-party punishment paradigm and white matter integrity and connectivity strength as determined by diffusion tensor imaging (DTI). We found that both increased white matter integrity at the right temporal-parietal junction (TPJ) and connectivity strength between the right TPJ and the dorsomedial prefrontal cortex (DMPFC) were associated with increased impartiality in the third-party punishment paradigm, i.e., reduced intergroup bias. Further, consistent with the role that these brain regions play in the mentalizing network, we found that these effects were mediated by mentalizing processes. Participants with greater white matter integrity at the right TPJ and connectivity strength between the right TPJ and the DMPFC employed mentalizing processes more equally for ingroup and outgroup members, and this non-biased use of mentalizing was associated with increased impartiality. The current results help shed light on the mechanisms of bias and, potentially, on interventions that promote impartiality over intergroup bias.
Social Psychology and Social Neuroscience, Department of Psychology, University of Bern, Switzerland; Center for Cognition, Learning and Memory, University of Bern, Switzerland. Electronic address: thomas.baumgartner@psy.unibe.ch.
Thomas
T
Baumgartner
Social Psychology and Social Neuroscience, Department of Psychology, University of Bern, Switzerland; Center for Cognition, Learning and Memory, University of Bern, Switzerland; Department of Psychology, University of Canterbury, Christchurch, New Zealand. Electronic address: kyle.nash@canterbury.ac.nz.
Kyle
K
Nash
Social Psychology and Social Neuroscience, Department of Psychology, University of Bern, Switzerland; Center for Cognition, Learning and Memory, University of Bern, Switzerland.
Christopher
C
Hill
Social Psychology and Social Neuroscience, Department of Psychology, University of Bern, Switzerland; Center for Cognition, Learning and Memory, University of Bern, Switzerland. Electronic address: daria.knoch@psy.unibe.ch.
Daria
D
Knoch
D000328:Adult; D001921:Brain / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology; D010296:Parietal Lobe / Q000033:anatomy & histology; D017397:Prefrontal Cortex / Q000033:anatomy & histology; D000068956:Prisoner Dilemma; D011678:Punishment; D063508:Social Discrimination; D012933:Social Identification; D013702:Temporal Lobe / Q000033:anatomy & histology; D056345:Theory of Mind; D066127:White Matter / Q000033:anatomy & histology*; D055815:Young Adult
Diffusion tensor imaging; Individual differences; Intergroup bias; Mentalizing; Neuroanatomy; White matter