title: Diminishing parochialism in intergroup conflict by disrupting the right temporo-parietal junction.
abstract: Individuals react to violation of social norms by outgroup members differently than to transgressions of those same norms by ingroup members: namely outgroup perpetrators are punished much more harshly than ingroup perpetrators. This parochial punishment pattern has been observed and extensively studied in social psychology and behavioral economics. Despite progress in recent years, however, little is known about the neural underpinnings of this intergroup bias. Here, we demonstrate by means of transcranial magnetic stimulation (TMS) that the transient disruption of the right, but not the left temporo-parietal junction (TPJ), reduces parochial punishment in a third-party punishment paradigm with real social groups. Moreover, we show that this observed TMS effect on parochial punishment is mediated by a classical punishment motive, i.e. retaliation. Finally, our data suggests that a change in perspective-taking might be the underlying mechanism that explains the impact of right TPJ disruption on retaliation motivation and parochial punishment. These findings provide the first causal evidence that the right TPJ plays a pivotal role in the implementation of parochial behaviors.
authors.affiliation: Social and Affective Neuroscience, Department of Psychology, University of Basel, Birmannsgasse 8, CH-4055 Basel, Switzerland. t.baumgartner@unibas.ch.
authors.forename: Thomas
authors.initials: T
authors.lastname: Baumgartner
authors.forename: Bastian
authors.initials: B
authors.lastname: Schiller
authors.forename: Jörg
authors.initials: J
authors.lastname: Rieskamp
authors.forename: Lorena R R
authors.initials: LR
authors.lastname: Gianotti
authors.forename: Daria
authors.initials: D
authors.lastname: Knoch
mesh_terms: D003220:Conflict, Psychological; D004644:Emotions / Q000502:physiology; D007839:Functional Laterality; D006126:Group Processes; D006801:Humans; D008297:Male; D008959:Models, Neurological; D009042:Motivation / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D011581:Psychological Tests; D011678:Punishment / Q000523:psychology; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis; D013702:Temporal Lobe / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: ingroup love; intergroup bias; normative behavior; outgroup hostility; parochialism; temporo-parietal junction; third-party punishment; transcranial magnetic stimulation