Behavioral, psychopharmacological and gender effects of stress on parochial altruism

人类是社会性的动物，他们与他人合作，考虑他们的福祉，并接受个人成本来帮助他们。然而，无私的行为并不总是以增加他人的福祉为目的。有时，个人会接受伤害他人的代价，即使伤害他人并不会带来更高的回报。利他主义的群体内合作和群体外的攻击，即所谓的狭隘利他主义，普遍存在，潜在的认知、神经和内分泌机制可能是共同进化的。在第一个筹资阶段，我们已经获得了行为和精神药理学证据，表明压力调节社会折扣，即依赖于社会距离的慷慨程度。我们已经证明，压力会选择性地增加对社交亲密的其他人(家人、朋友和其他群体成员)的慷慨，但不会增加社交遥远的其他人(邻居、陌生人等)的慷慨。有趣的是，我们第一项研究的相关数据以及第二项研究的精神药理学证据表明，内分泌应激反应中的去甲肾上腺素成分可能会减少而不是增加对他人的慷慨，这表明行为应激反应不仅仅是慷慨。此外，各学科之间有一个显著的共识，即压力也会增加攻击性倾向，例如，战斗反应。因此，我们假设，与压力相关的对社交亲密的人(内部群体)的慷慨增加，伴随着对外部群体成员的利他主义攻击的增加。此外，有假设认为，压力后慷慨和/或攻击性的变化与性别有关，尽管性别差异的证据还远未明确。因此，在第二个资助阶段，我们申请资助，以研究压力对教区利他主义的行为、神经内分泌和性别影响。我们将利用一种自然的内部群体-外部群体结构来研究现实的群体间竞争：政党选民之间存在的竞争。我们将使用几个行为任务来解决1)狭隘是否在总体上在男性和女性之间有所不同，即在没有压力的情况下，2)使用Trier社会压力测试的团体版本引发的心理社会压力是否放大了群体内的合作和外部的仇恨，以及3)这些对狭隘的压力影响是否与性别有关。最后，我们预测，通过精神药理学手段增强交感神经(去甲肾上腺素)，但不一定增强糖皮质激素活动(皮质醇)，可以模拟应激对地方性利他主义的影响。我们提出的研究将完善我们对压力的社会反应以及其中的性别差异的理解，但它们可能被概括为对促进和维持群体间冲突以及反社会行为的因素的重要见解。

Humans are social animals who cooperate with others, consider their well-being and accept personal costs to help them. However, selfless behavior is not always directed at increasing the well-being of other people. Sometimes, individuals accept costs to inflict harm on others, even if harming others does not result in higher own-payoff. Altruistic ingroup cooperation together with outgroup aggression, so-called parochial altruism, is widespread and the underlying cognitive, neural and endocrine mechanisms possibly coevolved. In a first funding phase, we have obtained behavioral and psychopharmacological evidence that stress modulates social discounting, i.e., social-distance-dependent levels of generosity. We have shown that stress selectively increases generosity towards socially close others (family, friends and other ingroup members), but not socially remote others (neighbors, strangers etc.). Interestingly, correlational data from our first study as well as psychopharmacological evidence from a second study suggests that the noradrenergic component of the endocrine stress response may decrease, rather than increase, generosity towards others, suggesting that there is more to the behavioral stress response than mere generosity. Moreover, there is remarkable consensus across disciplines that stress can also increase aggressive tendencies, e.g., fighting responses. We therefore hypothesize that the stress-related increase in generosity towards socially close people (ingroup) goes along with an increase in altruistic aggression against outgroup members. Moreover, it has been hypothesized that changes in generosity and/or aggression after stress are gender-dependent, although evidence for gender differences is far from clear. In a second funding phase, we therefore apply for funding to investigate the behavioral, neuroendocrine and gender effects of stress on parochial altruism. We will exploit a natural ingroup-outgroup structure to study realistic intergroup rivalry: existing rivalries between political party voters. We will employ several behavioral tasks allowing us to address 1) whether parochialism is different between men and women in general, i.e., in the absence of stress, 2) whether psychosocial stress, elicited using the group version of the Trier Social Stress Test, amplifies ingroup cooperation together with outgroup hate, and 3) whether these stress-effects on parochialism are gender-dependent. Finally, we predict that enhancing sympathetic (noradrenaline), but not necessarily glucocorticoid activity (cortisol) by psychopharmacological means mimics the effects of stress on parochial altruism. Our proposed studies will refine our understanding of the social response to stress, and gender differences therein, but they may be generalized to yield important insights into the factors promoting and maintaining intergroup conflicts as well as antisocial behavior.