Not on my team: Medial prefrontal cortex responses to ingroup fusion and unfair monetary divisions

TY - JOUR

T1 - Not on my team

T2 - Medial prefrontal cortex responses to ingroup fusion and unfair monetary divisions

AU - Apps, Matthew A J

AU - McKay, Ryan

AU - Azevedo, Ruben T

AU - Whitehouse, Harvey

AU - Tsakiris, Manos

N1 - © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.

PY - 2018/8

Y1 - 2018/8

N2 - OBJECTIVE: People are highly attuned to fairness, with people willingly suffering personal costs to prevent others benefitting from unfair acts. Are fairness judgments influenced by group alignments? A new theory posits that we favor ingroups and denigrate members of rival outgroups when our personal identity is fused to a group. Although the mPFC has been separately implicated in group membership and fairness processing, it is unclear whether group alignments affect medial prefrontal cortex (mPFC) activity in response to fairness. Here, we examine the contribution of different regions of the mPFC to processing from ingroup and outgroup members and test whether its response differs depending on how fused we are to an ingroup.METHODS: Subjects performed rounds of the Ultimatum Game, being offered fair or unfair divisions of money from supporters of the same soccer team (ingroup), the fiercest rival (outgroup) or neutral individuals whilst undergoing functional Magnetic Resonance Imaging (fMRI).RESULTS: Strikingly, people willingly suffered personal costs to prevent outgroup members benefitting from both unfair and fair offers. Activity across dorsal and ventral (VMPFC) portions of the mPFC reflected an interaction between fairness and group membership. VMPFC activity in particular was consistent with it coding one's fusion to a group, with the fairness by group membership interaction correlating with the extent that the responder's identity was fused to the ingroup.CONCLUSIONS: The influence of fusion on social behavior therefore seems to be linked to processing in the VMPFC.

AB - OBJECTIVE: People are highly attuned to fairness, with people willingly suffering personal costs to prevent others benefitting from unfair acts. Are fairness judgments influenced by group alignments? A new theory posits that we favor ingroups and denigrate members of rival outgroups when our personal identity is fused to a group. Although the mPFC has been separately implicated in group membership and fairness processing, it is unclear whether group alignments affect medial prefrontal cortex (mPFC) activity in response to fairness. Here, we examine the contribution of different regions of the mPFC to processing from ingroup and outgroup members and test whether its response differs depending on how fused we are to an ingroup.METHODS: Subjects performed rounds of the Ultimatum Game, being offered fair or unfair divisions of money from supporters of the same soccer team (ingroup), the fiercest rival (outgroup) or neutral individuals whilst undergoing functional Magnetic Resonance Imaging (fMRI).RESULTS: Strikingly, people willingly suffered personal costs to prevent outgroup members benefitting from both unfair and fair offers. Activity across dorsal and ventral (VMPFC) portions of the mPFC reflected an interaction between fairness and group membership. VMPFC activity in particular was consistent with it coding one's fusion to a group, with the fairness by group membership interaction correlating with the extent that the responder's identity was fused to the ingroup.CONCLUSIONS: The influence of fusion on social behavior therefore seems to be linked to processing in the VMPFC.

KW - Adult

KW - Female

KW - Games, Experimental

KW - Group Processes

KW - Humans

KW - Interpersonal Relations

KW - Magnetic Resonance Imaging/methods

KW - Male

KW - Prefrontal Cortex/diagnostic imaging

KW - Social Behavior

U2 - 10.1002/brb3.1030

DO - 10.1002/brb3.1030

M3 - Article

C2 - 29931824

VL - 8

SP - e01030

JO - Brain and Behavior

JF - Brain and Behavior

SN - 2162-3279

IS - 8

ER -