title: The evolution of extreme cooperation via shared dysphoric experiences.
abstract: Willingness to lay down one's life for a group of non-kin, well documented historically and ethnographically, represents an evolutionary puzzle. Building on research in social psychology, we develop a mathematical model showing how conditioning cooperation on previous shared experience can allow individually costly pro-group behavior to evolve. The model generates a series of predictions that we then test empirically in a range of special sample populations (including military veterans, college fraternity/sorority members, football fans, martial arts practitioners, and twins). Our empirical results show that sharing painful experiences produces "identity fusion" - a visceral sense of oneness - which in turn can motivate self-sacrifice, including willingness to fight and die for the group. Practically, our account of how shared dysphoric experiences produce identity fusion helps us better understand such pressing social issues as suicide terrorism, holy wars, sectarian violence, gang-related violence, and other forms of intergroup conflict.
authors.affiliation: Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 51-53 Banbury Road, Oxford OX2 6PE UK.
authors.forename: Harvey
authors.initials: H
authors.lastname: Whitehouse
authors.affiliation: Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 51-53 Banbury Road, Oxford OX2 6PE UK.|Centre for Research in Psychology, Behaviour and Achievement, Coventry University, Priory Street, Coventry CV1 5FB, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Jong
authors.affiliation: Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 51-53 Banbury Road, Oxford OX2 6PE UK.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Buhrmester
authors.affiliation: Departamento de Psicología Social y de las Organizaciones Universidad Nacional de Educación a Distancia, UNED C/Juan del Rosal 10, Dcho, 1.58 Madrid, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Gómez
authors.affiliation: Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 51-53 Banbury Road, Oxford OX2 6PE UK.|Melbourne School of Psychological Sciences, The University of Melbourne, Australia.
authors.forename: Brock
authors.initials: B
authors.lastname: Bastian
authors.affiliation: Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 51-53 Banbury Road, Oxford OX2 6PE UK.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Kavanagh
authors.affiliation: Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 51-53 Banbury Road, Oxford OX2 6PE UK.
authors.forename: Martha
authors.initials: M
authors.lastname: Newson
authors.affiliation: RAND Corporation, 1200 South Hayes Street, Arlington, VA 22202-5050 USA.
authors.forename: Miriam
authors.initials: M
authors.lastname: Matthews
authors.affiliation: Institute of Cognition and Culture, Queen's University Belfast, 2-4 Fitzwilliam Street, Belfast, BT7 1NN UK.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Lanman
authors.affiliation: ARC Centre of Excellence in Cognition and its Disorders, Department of Psychology, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK.
authors.forename: Ryan
authors.initials: R
authors.lastname: McKay
authors.affiliation: Department of Ecology and Evolutionary Biology, Department of Mathematics, National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996 USA.
authors.forename: Sergey
authors.initials: S
authors.lastname: Gavrilets
mesh_terms: D000328:Adult; D003299:Cooperative Behavior; D005059:Euphoria / Q000502:physiology; D006801:Humans; D008297:Male; D008398:Masochism / Q000523:psychology*; D008399:Mass Behavior; D008960:Models, Psychological; D009042:Motivation / Q000502:physiology; D023481:Terrorism / Q000523:psychology*; D014754:Violence / Q000523:psychology*