title: Neural segregation of objective and contextual aspects of fairness.
abstract: Perception of fairness can influence outcomes in human exchange. However, an inherent subjectivity in attribution renders it difficult to manipulate fairness experimentally. Here using a modified ultimatum game, within a varying social context, we induced a bias in human subjects' acceptance of objectively identical offers. To explain this fairness-related behavior, we use a computational model to specify metrics for the objective and contextual aspects of fairness, testing for correlations between these model parameters and brain activity determined using functional magnetic resonance imaging. We show that objective social inequality, as defined by our model, is tracked in posterior insula cortex. Crucially, this inequality is integrated with social context in posterior and mid-insula, consistent with construction of a fairness motivation that flexibly adapted to the social environment. We suggest that the dual importance of objective and contextual aspects to fairness we highlight might explain seemingly inconsistent societal phenomena, including public attitudes to income disparities.
authors.affiliation: Wellcome Trust Centre for Imaging Neuroscience, Institute of Neurology, University College London, London WC1N 3BG, United Kingdom. n.wright@fil.ion.ucl.ac.uk
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Wright
authors.forename: Mkael
authors.initials: M
authors.lastname: Symmonds
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Fleming
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Dolan
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D003657:Decision Making / Q000502:physiology*; D005260:Female; D005717:Games, Experimental; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007398:Interpersonal Relations; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008960:Models, Psychological; D010100:Oxygen / Q000097:blood; D011594:Psychometrics; D012935:Social Justice / Q000523:psychology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D010100:Oxygen