The Evolutionary Roots of Social Comparison

社会比较过程是人类行为的一个基本特征，其潜在的心理机制和过程在过去几十年里得到了深入的研究。然而，到目前为止，人们对社会比较的进化基础知之甚少。非人类动物也会进行自我与他人的比较吗？还是这些广泛的社会比较仅限于人类？对非人类灵长类动物的研究表明，动物可能对他人的行为很敏感，并能调整自己的反应。例如，黑猩猩和卷尾猴拒绝参与实验，如果伴侣动物在同样的任务中得到更好的奖励。乌鸦和渡鸦也表现出这种“不平等厌恶”。这些研究表明，社会比较可能存在进化基础，但直到现在，其潜在机制还没有被系统地探索过。为了填补这一重要的理解空白，本项目旨在阐明社会比较的进化根源。我们将采用比较的方法，并将社会心理学的实验范式与动物行为研究方法相结合。具体来说，与人类社会比较过程的经典研究类似，我们将研究伴侣的表现如何影响猴子（长尾猕猴，Macaca fascicularis）和鸟类（腐肉乌鸦，Corvus corone）的表现行为。这些物种特别擅长社会任务，因此非常适合我们的比较研究。更具体地说，为了研究社会比较的特定特征在非人类动物中是否已经很明显，我们将使用已经开发的经典范式来研究人类社会比较的潜在机制。通过在触摸屏上的平行表演，我们将研究猴子和鸟类的社会比较是否受到受试者和合作演员表演之间的相对差异、他们之间的个人关系（第一行）、受试者在其群体中的社会地位（第二行）以及将焦点分别转移到相似或不同特征上的先验启动程序（第三行）的影响。为了验证比较方法，我们也将对人类参与者进行1号线和3号线的实验。此外，2号线的实验与P7密切合作，反映了我们追求真正跨学科方法的雄心。

Social comparison processes are a fundamental characteristic of human behavior, and the underlying psychological mechanisms and processes have been intensively investigated in the last decades. Yet, until now, relatively little is known about the evolutionary foundations of social comparisons. Do non-human animals also engage in self-other comparisons or are these extensive social comparisons restricted to humans? Studies on non-human primates indicate that animals may be sensitive to the actions of others and adjust their responses. Chimpanzees and capuchin monkeys, for example, refuse to participate in experiments, if a partner animal is receiving better rewards for the same task. Crows and ravens also show this `inequity aversion¿. These studies suggest that there may be an evolutionary basis for social comparisons, but until now the underlying mechanisms have never been explored systematically. In an attempt to fill this important gap in understanding, the present project aims to elucidate the evolutionary roots of social comparisons. We will adopt a comparative approach and combine experimental paradigms from social psychology with animal behavior research methods. Specifically, in an analogy to classic research on social comparison processes in humans, we will examine how the performance of a partner influences subjects¿ performance behavior in monkeys (long-tailed macaques, Macaca fascicularis) and birds (carrion crows, Corvus corone). These species are particularly skilled at social tasks and thus ideally suited for our comparative research endeavor. More specifically, to examine whether specific features of social comparisons are already evident in non-human animals, we will use classic paradigms that have been developed to examine the underlying mechanisms of social comparisons in humans. Using parallel performances on touch-screen setups, we will investigate whether social comparisons in monkeys and birds are influenced by the relative difference between the subject¿s and the co-actor¿s performance as well as the personal relationship between them (Line 1), the social status of the subject within its group (Line 2) as well as prior priming procedures to shift the focus to similarity or dissimilarity features, respectively (Line 3). To validate the comparative approach we will conduct the experiments of Line 1 and 3 with human participants, too. Furthermore, experiments of Line 2 are in close collaboration to P7 reflecting our ambition to strive for a truly interdisciplinary approach.