title: Ingroup/outgroup membership modulates fairness consideration: neural signatures from ERPs and EEG oscillations.
abstract: Previous studies have shown that ingroup/outgroup membership influences individual's fairness considerations. However, it is not clear yet how group membership influences brain activity when a recipient evaluates the fairness of asset distribution. In this study, subjects participated as recipients in an Ultimatum Game with alleged members of both an experimentally induced ingroup and outgroup. They either received extremely unequal, moderately unequal, or equal offers from proposers while electroencephalogram was recorded. Behavioral results showed that the acceptance rates for unequal offers were higher when interacting with ingroup partners than with outgroup partners. Analyses of event related potentials revealed that proposers' group membership modulated offer evaluation at earlier processing stages. Feedback-related negativity was more negative for extremely and moderately unequal offers compared to equal offers in the ingroup interaction whereas it did not show differential responses to different offers in the outgroup interaction. Analyses of event related oscillations revealed that the theta power (4-6 Hz) was larger for moderately unequal offers than equal offers in the ingroup interaction whereas it did not show differential responses to different offers in the outgroup interaction. Thus, early mechanisms of fairness evaluation are strongly modulated by the ingroup/outgroup membership of the interaction partner.
authors.affiliation: School of Humanities and Social Sciences, Institute of Psychological and Cognitive Sciences, Fuzhou University, Fuzhou, 350116, China.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Humanities and Social Sciences, Institute of Psychological and Cognitive Sciences, Fuzhou University, Fuzhou, 350116, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: School of Humanities and Social Sciences, Institute of Psychological and Cognitive Sciences, Fuzhou University, Fuzhou, 350116, China.
authors.forename: Liying
authors.initials: L
authors.lastname: Bai
authors.affiliation: Institute of Developmental Psychology, Beijing Normal University, 100875, China.
authors.forename: Chongde
authors.initials: C
authors.lastname: Lin
authors.affiliation: Department of Psychology, University of Osnabrück, 49074 Osnabrück, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Osinsky
authors.affiliation: Department of Psychology, Julius-Maximilians-University Würzburg, 97070, Würzburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Hewig
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D025461:Feedback, Physiological; D005260:Female; D006801:Humans; D008297:Male; D025341:Principal Component Analysis; D011930:Reaction Time; D018910:Video Games; D055815:Young Adult