The narrow gap between norms and cooperative behaviour in a reindeer herding community

Cooperation evolves on social networks and is shaped, in part, by norms: beliefs and expectations about the behaviour of others or of oneself. Networks of cooperative social partners and associated norms are vital for pastoralists, such as Saami reindeer herders in northern Norway. However, little is known quantitatively about how norms structure pastoralists' social networks or shape cooperation. Saami herders reported their social networks and participated in field experiments, allowing us to gauge the overlap between reported and emergent cooperation. We show that individuals' perceptions of reciprocal cooperation within their social networks exceeded actual reciprocity, although both occurred frequently and were concentrated within herding groups. Herders with more extensive cooperation networks received more rewards in an economic game. Although herders overestimated reciprocal helping, cooperation in this community was still extensive, suggesting that perceived norms potentially a...

合作行为在社交网络中演化，并在一定程度上受规范（norms）塑造——此处的规范指对他人或自身行为的信念与预期。拥有合作社交伙伴的网络及相关规范，对于游牧民而言至关重要，例如挪威北部的萨米（Saami）驯鹿牧民。然而，目前尚缺乏定量研究以揭示规范如何塑造游牧民的社交网络结构，或是影响合作行为。萨米牧民报告了自身的社交网络，并参与了实地实验，这使得我们能够衡量自我报告的合作与涌现合作（emergent cooperation）之间的重合度。我们的研究结果显示，个体对自身社交网络内互惠合作（reciprocal cooperation）的认知，超过了实际发生的互惠行为——尽管二者均频繁出现，且集中分布于牧民群体当中。拥有更广泛合作网络的牧民，在经济博弈实验中获得了更多奖励。尽管牧民高估了互惠互助的程度，但该社群内的合作依然广泛，这表明感知到的规范可能在……