The reason why cooperation occurs in repeated games has remained a puzzle. Earlier literature has maintained that reciprocal behavior that gives rise to cooperation can be entirely self-regarding. However, experimental evidence has shown that reciprocal behavior is other-regarding in many 1-shot games. This other-regarding behavior is believed to have an emotional foundation. We hypothesized that emotions play a role in reciprocal behavior in repeated games as well. We tested this hypothesis by measuring the psychophysiological correlates of emotions from pairs of subjects as they played a repeated Cournot duopoly game. The players, who were in different rooms and remained anonymous to each other, made adjustment decisions to their production quantities that determined their payoffs in each round. Autonomic nervous system arousal was activated when the payoffs of both players decreased in a round, whereas positive affect was expressed when the payoffs of both players increased in a round. The disgust expression was related to a player’s own 1-sided increase in the payoff. Anger was expressed occasionally but less frequently when the outcome was the player’s ideal outcome. An upward adjustment of the production quantity was observed when the other player did not cooperate. This had the effect of decreasing the payoffs of both players, and this was also related to an increase in the level of arousal. Our results provide evidence on how emotions are present in reciprocal behavior in a repeated social dilemma game. The results challenge recent behavioral research that has advocated self-regarded motivations of cooperation in repeated games.

中文翻译：

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重复古诺双头垄断游戏中的情绪：心理生理学实验。

重复博弈中出现合作的原因一直是个谜。早期的文献认为，导致合作的互惠行为可以完全是自私的。然而，实验证据表明，在许多单杆游戏中，互惠行为是其他方面的。这种与他人有关的行为被认为具有情感基础。我们假设情绪在重复游戏中的交互行为中也起作用。我们通过测量一对受试者在重复古诺双头垄断游戏时情绪的心理生理相关性来检验这一假设。处于不同房间并且彼此保持匿名的玩家对他们的产量做出调整决定，这决定了他们在每一轮中的收益。自主神经系统唤醒是在一轮双方的收益都减少时激活，而当双方的收益在一轮中增加时，则表现出积极的影响。厌恶的表达与玩家自己的收益单方面增加有关。当结果是玩家的理想结果时，愤怒偶尔会表达，但不那么频繁。当其他玩家不合作时，观察到产量向上调整。这具有降低双方玩家收益的效果，这也与提高唤醒水平有关。我们的研究结果提供了在重复的社会困境博弈中情绪如何在互惠行为中存在的证据。结果挑战了最近提倡在重复博弈中以自我为中心的合作动机的行为研究。