title: Fear or greed? Oxytocin regulates inter-individual conflict by enhancing fear in men.
abstract: People may choose non-cooperation in social dilemmas either out of fear (if others choose to defect) or out of greed (when others choose to cooperate). Previous studies have shown that exogenous oxytocin motivates a "tend and defend" pattern in inter-group conflict in which oxytocin stimulates in-group cooperation and out-group defense. Using a double-blind placebo-controlled design combined with a modified Prisoner's dilemma game (PDG), we examined the effect of oxytocin on social motivations in inter-individual conflict in men. Results showed that compared with the placebo group, oxytocin-exposed participants were less cooperative in general. Specifically, oxytocin amplified the effect of fear on defection but did not influence the effect of greed. Another non-social control study confirmed participants' decisions were sensitive to social factors. Our findings suggest that even when social group conflict is removed, oxytocin promotes distrust of strangers in "me and you" inter-individual conflict by elevating social fear in men.
authors.affiliation: School of Psychology, Center for Studies of Psychological Application and Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Key Laboratory for Neuroinformation, Center for Information in Medicine, University of Electronic Science and Technology of China, Chengdu, China.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Kendrick
authors.affiliation: School of Psychology, Center for Studies of Psychological Application and Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou, China; Department of Psychology, National University of Singapore, Singapore; Neurobiology/Ageing Programme, Center for Life Sciences, National University of Singapore, Singapore; Institute for Neurotechnology (SINAPSE), Center for Life Sciences, National University of Singapore, Singapore. Electronic address: psyyr@nus.edu.sg.
authors.forename: Rongjun
authors.initials: R
authors.lastname: Yu
mesh_terms: D000328:Adult; D003220:Conflict, Psychological; D003299:Cooperative Behavior; D003657:Decision Making / Q000187:drug effects; D004311:Double-Blind Method; D005239:Fear / Q000187:drug effects*; D000067571:Financial Statements; D006126:Group Processes; D006801:Humans; D007206:Individuality; D007398:Interpersonal Relations; D008297:Male; D009042:Motivation / Q000187:drug effects*; D010121:Oxytocin / Q000008:administration & dosage / Q000494:pharmacology*; D000068956:Prisoner Dilemma; D012919:Social Behavior; D035502:Trust / Q000523:psychology; D055815:Young Adult
chemical_list: D010121:Oxytocin
keywords: Cooperation; Emotion; Fear; Greed; Oxytocin