In-Group Bounded Cooperation: Carsten K.W. De Dreu University of Amsterdam Department of Psychology, and Center for Experimental Economics and Political Decision Making (CREED) and Netherlands Institute for Advanced Study

Background and Overview –Multilevel Perspective –1. Individuals are nested in groups that compare, cooperate, compete with other groups; Individuals are interdependent within and between groups –2. Individuals rely on their in-group for survival/prosperity; Group survival/prosperity depends on individual contributions –3. Individuals are prepared to (enforce in others) 4Cs Cooperating:making costly contributions to group efficiencyCooperating:making costly contributions to group efficiency Conforming: aligning with majority views, norms, practicesConforming: aligning with majority views, norms, practices Creating: advancing new and useful insights/ideas/productsCreating: advancing new and useful insights/ideas/products Competing: aggressing those that threaten in-group functioningCompeting: aggressing those that threaten in-group functioning

Background and Overview –Multilevel Perspective (c’tnd) –4. These 4Cs should be particularly likely when serving in-group (rather than out-group), and can be traced to the individual (rather than not)can be traced to the individual (rather than not) reputation; (in)direct reciprocity prevent in-group harm (vs. promoting in-group gain)prevent in-group harm (vs. promoting in-group gain) loss aversion; survival trumps prosperity needs; reactive vs. instrumental aggression –5. Because of evolutionary pressures (viz. Darwin), humans may be biologically prepared for In-group Bounded 4Cs; if true 4Cs should be readily observable in “abstract” settings4Cs should be readily observable in “abstract” settings 4Cs should be intuitive, and not requiring deliberation4Cs should be intuitive, and not requiring deliberation 4Cs should have clear correlates in (evolutionary ancient, sub- cortical) neurobiological circuitries and systems.4Cs should have clear correlates in (evolutionary ancient, sub- cortical) neurobiological circuitries and systems.

Background and Overview: Key Findings Evidence accumulates that 4Cs are (i)motivated by a desire to benefit the in-group and its members, rather than to hurt or derogate competing outgroups; (ii)Stronger when mechanism for (in)direct reciprocity are present; (iii)Stronger when stable preferences are pro-social rather than pro-self (iv)Intuitive and habitual rather than calculated and pre-meditated (v)Enhanced under increased availability of oxytocin, a hypothalamic neuropeptide involved in pair-bond formation, parent-offspring interactions, and maternal defense.

(i) motivated by in-group love not out-group hate Economic Games (Dictator, Trust Game, PDG, PPG); Protagonist classified as in- group vs. out-group, stranger; k = 205 effect sizes; Random Effects Model Balliet, Wu, De Dreu, Psych Bull 2014 In-group bounded cooperation

(ii) stronger when (in)direct reciprocity is enabled –Full Info: Experiments in which decision maker knows that partner knows decision maker si from same/different group vs –Partial Info: Experiments in which decision maker knows that partner does NOT know decision maker’s group In-group bounded cooperation Balliet, Wu, De Dreu, Psych Bull 2014

tronger when stable preferences are pro-social rather than pro-self (iii) stronger when stable preferences are pro-social rather than pro-self – –Intergroup Competition Game – –Players pre-classified as cooperators (pro-socials) vs. non-cooperators (pro-selves) – –Players have (no) option to punish in-group members following (lack of) investment Fig.2 Mean aggregate conflict expenditures (total of both groups) over the 20 rounds. The shaded area illustrates the range in which total investments in fighting exceed the value of the prize. From Abbink et al., 2012; Economics Letters Abbink, Brandts et al., Econ Lett 2012

tronger when stable preferences are pro-social rather than pro-self (iii) stronger when stable preferences are pro-social rather than pro-self ( De Dreu, Group Process Intergr Relat, 2010)

(iv) intuitive rather than calculated and pre-meditated (De Dreu, Dussel, & Ten Velden, Fr Human Neuroscience, 2015)

(iv) intuitive rather than calculated and pre-meditated (De Dreu, Dussel, & Ten Velden, Fr Human Neuroscience, 2015)

(v) enhanced under increased availability of oxytocin Dreu, Horm & Behav, 2012; De Dreu & Kret, Biol Psychiatry 2015

(v) enhanced under increased availability of oxytocin ( Overview of Materials and Methods) MedicationMedication –Double-Blind Placebo Controlled Study Designs Syntocinon Spray (Oxytocin). Placebo manufactured for this study (GCP, Helsinki Protocols).Syntocinon Spray (Oxytocin). Placebo manufactured for this study (GCP, Helsinki Protocols). Intranasal administration; loading time 35-40min; 20 – 30 Ss per treatment conditionIntranasal administration; loading time 35-40min; 20 – 30 Ss per treatment condition SubjectsSubjects –Healthy males (age M = 21); Tested between Noon—4PM; no smoking or intense physical exercise 2h prior to test sessionTested between Noon—4PM; no smoking or intense physical exercise 2h prior to test session Experimental Procedures and TasksExperimental Procedures and Tasks –Individual testing in soundproof cubicles; computer-guided; self-paced Instructions, behavioral responses, post-test questions, debriefingInstructions, behavioral responses, post-test questions, debriefing No deception; performance-contingent pay (range 0 – 35€).No deception; performance-contingent pay (range 0 – 35€).

(v) enhanced under increased availability of oxytocin Keep 1€ = 1€ In-Group Stallen, De Dreu et al., Psych Science, 2012

(v) enhanced under increased availability of oxytocin 10€ Keep 1€ = 1€ In-Group Love Out-Group Hate 1€ = +0.5€ 1€ = -0.5€ In-Group Out-Group De Dreu et al., Science, 2010

(v) enhanced under increased availability of oxytocin In PDG, Defection is motivated by Greed (Temptation) and/or Fear (Sucker) Payoffs manipulated to increase/reduce Fear (i.e., vulnerability to exploitation by out- group) and Greed (i.e., temptation to exploit out-group) De Dreu et al., Science, 2010; PLoS One, C C D D C D C C D D C D Subject Out-Group

(v) enhanced under increased availability of oxytocin Summary:Summary: Oxytocin promotes conformity, esp. to in-groupOxytocin promotes conformity, esp. to in-group Oxytocin promotes in-group bounded cooperation and trustOxytocin promotes in-group bounded cooperation and trust Oxytocin promotes defense-motivated competitionOxytocin promotes defense-motivated competition No evidence for out-group spite and exploitative aggressionNo evidence for out-group spite and exploitative aggression

Summary of Key Findings Evidence accumulates that 4Cs (cooperating, conforming, creating, competing) are: (i)motivated by a desire to benefit the in-group and its members, rather than to hurt or derogate competing outgroups; (ii)Stronger when mechanism for (in)direct reciprocity are present; (iii)Stronger when stable preferences are pro-social rather than pro-self (iv)Intuitive and habitual rather than calculated and pre-meditated (v)Enhanced under increased availability of oxytocin, a hypothalamic neuropeptide involved in pair-bond formation, parent-offspring interactions, and maternal defense.

Implications  Fitting an evolutionary account (Theory of Bounded Generalized Reciprocity) on the root causes of human propensity for cooperation specifically (and group living in general)  New avenues for future research:  structurally mapping 4Cs (little w/r Creating);  role of social identity;  other neurohormonal mechanisms (e.g., testosterone, cortisol)  calibrating intervention in (reducing) prejudice and (reducing) intergroup violence  Reconciling findings with work on intergroup contact, diffusion of innovation, between-group exchange and trade  Predicting when the world seizes to exist

Thank You – –And… Conflict & Creativity Lab: Hillie Aaldering, Matthijs Baas, Lindy Greer, Michel Handgraaf, Mariska Kret, Shaul Shalvi, Femke ten Velden, Eric van Dijk, Gerben Van Kleef, and Jorg Gross Funding Agencies: Roy Netherl Acad Sci; Netherl Sci Found; Dutch Judicial Council; U of Amsterdam

Disclosure Ethics approval, obtained written informed consentEthics approval, obtained written informed consent Complied with Helsinki Protocol;Complied with Helsinki Protocol; Did not involve deception; Ss received payment depending on performance;Did not involve deception; Ss received payment depending on performance; No conflict of interest; funding sources include:No conflict of interest; funding sources include: