Oxytocin modulates selection of allies in intergroup conflict

Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 09/2012; 279(1731):1150-4. DOI: 10.1098/rspb.2011.1444
Source: PubMed


In intergroup competition and conflict, humans benefit from coalitions with strong partners who help them to protect their in-group and prevail over competing out-groups. Here, we link oxytocin, a neuropeptide produced in the hypothalamus, to ally selection in intergroup competition. In a double-blind placebo-controlled experiment, males self-administered oxytocin or placebo, and made selection decisions about six high-threat and six low-threat targets as potential allies in intergroup competition. Males given oxytocin rather than placebo viewed high-threat targets as more useful allies and more frequently selected them into their team than low-threat targets.

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    • "In free-living meerkats, infusion of oxytocin versus placebo motivated an array of cooperative behaviors including longer time-on-guard [37], in lactating rats bred for high anxiety it motivated maternal aggression against virgin intruders [38], and in breast-feeding mothers plasma oxytocin predicted hostility towards a female stranger [39]. In humans, intranasal oxytocin versus placebo motivated more positive evaluations of the in-group compared to rivaling out-groups [40], and non-cooperation towards rivaling out-groups especially when out-group threat was high [17], [41]. However, because in these studies the individual's self-interest perfectly correlated with in-group interests, it is unknown whether, in intergroup competition, oxytocin motivates protection of (i) immediate self-interest, (ii) vulnerable in-group members, or (iii) some combination of both. "
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    ABSTRACT: Intergroup conflict is often driven by an individual's motivation to protect oneself and fellow group members against the threat of out-group aggression, including the tendency to pre-empt out-group threat through a competitive approach. Here we link such defense-motivated competition to oxytocin, a hypothalamic neuropeptide involved in reproduction and social bonding. An intergroup conflict game was developed to disentangle whether oxytocin motivates competitive approach to protect (i) immediate self-interest, (ii) vulnerable in-group members, or (iii) both. Males self-administered oxytocin or placebo (double-blind placebo-controlled) and made decisions with financial consequences to themselves, their fellow in-group members, and a competing out-group. Game payoffs were manipulated between-subjects so that non-cooperation by the out-group had high vs. low impact on personal payoff (personal vulnerability), and high vs. low impact on payoff to fellow in-group members (in-group vulnerability). When personal vulnerability was high, non-cooperation was unaffected by treatment and in-group vulnerability. When personal vulnerability was low, however, in-group vulnerability motivated non-cooperation but only when males received oxytocin. Oxytocin fuels a defense-motivated competitive approach to protect vulnerable group members, even when personal fate is not at stake.
    Full-text · Article · Nov 2012 · PLoS ONE
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    • "The third possible explanation proceeds on the basis of the assumption that the availability of oxytocin in the brain alters cognitive-emotional schemas of others as untrustworthy, undependable, and unreliable into more benevolent views of others (Bartz et al., 2011). Indeed, intranasal oxytocin makes people less aversive of angry faces (Evans et al., 2010), more likely to accept allies displaying high — rather than low threat (De Dreu et al., 2011b), it de-activates neural circuitries associated with betrayal aversion (Baumgartner et al., 2008), increases perceived facial trustworthiness and attractiveness (Theodoridou et al., 2009), and activates neural circuitries associated with empathy such as the inferior frontal gyrus and the ventromedial prefrontal cortex Figure 2 (A) Oxytocin leads to stronger feeling at ease than placebo among individuals high (+1SD) but not low (À1SD) in attachment avoidance. (B) Oxytocin leads individuals to select secure attachment scenarios more, and insecure attachment scenarios less, than placebo. "
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    ABSTRACT: An experiment examined whether and how the relationship between individual differences in social attachment and cooperation is modulated by brain oxytocin, a neuropeptide implicated both in parent-child bonding, and in social approach. Healthy males completed a validated attachment style measure, received intranasal oxytocin or placebo, and privately chose between cooperation and non-cooperation in an incentivized social dilemma with an anonymous stranger. Attachment anxiety--the tendency to fear rejection by others--had few effects and was not modulated by oxytocin. However, oxytocin interacted with attachment avoidance--the tendency to fear dependency and closeness in interpersonal relations. Especially among participants high rather than low in attachment avoidance, oxytocin reduced betrayal aversion, and increased trust and cooperation compared to placebo. Effects of attachment avoidance and oxytocin on cooperation were mediated by betrayal aversion, and not by affiliation tendencies.
    Full-text · Article · Nov 2011 · Psychoneuroendocrinology
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    ABSTRACT: Purpose – Conflict models in international relations, particularly foreign policy decision-making models, have relied extensively upon the logic and explanatory power of rational choice theories. These models suggest that actors select a strategy, or foreign policy, that will maximize expected utility given the information available at the time and the beliefs about the state of the international system. However, prospect theory has shown us that context during conflict matters and evolutionary theory, supported by biopolitical science, has revealed how individual characteristics, and human nature in general, influence the decision-making process. Through these approaches, we can begin to understand that a comprehensive model of foreign policy analysis (FPA) requires an examination of how human behavioral traits are affected by different conflict scenarios, such as a context of ambiguity and risk as opposed to one of certainty.Approach – Drawing from recent neuroscience findings and taking a life sciences approach, this chapter seeks to challenge the rational choice theories of FPA by constructing a model of international conflict inclusive of a neural theory of decision-making.Findings – With a model founded on an evolutionary analysis and a neural theory of decision-making, we can begin to better understand not only the causes of war and deterrence failures, but also the frequency and intensity of genocide and ethnic conflict in the international system.Originality/value – Recent advances and technological breakthroughs in the fields of behavioral genetics and social neuroscience have revealed a plethora of new information valuable to the study of international conflict that shed light on brain-behavior processes within different decision-making contexts.
    No preview · Article · Jun 2012 · Research in Biopolitics
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