Developmental shifts in social cognition: socio-emotional biases across the lifespan in rhesus monkeys

Humans exhibit a suite of developmental changes in social cognition across the lifespan. To what extent are these developmental patterns unique? We first review several social domains in which humans undergo critical ontogenetic changes in socio-cognitive processing, including social attention and theory of mind. We then examine whether one human developmental transition—a shift in socioemotional preferences—also occurs in nonhuman primates. Specifically, we experimentally measured socioemotional processing in a large population of rhesus macaques (Macaca mulatta) ranging from infancy to old age. We tested whether macaques, like humans, also exhibited developmental shifts from a negativity bias at younger ages, indicating preferential attention to negative socioemotional stimuli, to a positivity bias at older ages. We first assessed monkeys’ (n = 337) responses to negative socioemotional stimuli by comparing their duration of looking towards photos of negative conspecific signals (threat displays) versus matched neutral expressions. In contrast to the pattern observed in humans, we found that older monkeys were more attentive to negative emotional stimuli than were younger monkeys. In a second study, we used the same method to examine monkeys’ (n = 132) attention to positive (affiliative displays) versus matched neutral expressions. Monkeys did not exhibit an overall preference for positive stimuli, nor major age-related changes in their attention. These results indicate that while monkeys show robust ontogenetic shifts in social preferences, they differ from humans by exhibiting an increasing negativity bias with age. Studies of comparative cognitive development can therefore provide insight into the evolutionary origins of human socio-cognitive development.

人类在整个生命周期中，社会认知会发生一系列发育变化。这些发育模式究竟具有多大程度的独特性？我们首先回顾了人类在社会认知加工过程中经历关键个体发育变化的若干社会领域，其中包括社会注意（social attention）与心理理论（Theory of Mind）。随后我们探究了人类的一项发育转变——社会情绪偏好的转变——是否同样存在于非人灵长类动物中。具体而言，我们通过实验对从幼年到老年的大种群恒河猴（Macaca mulatta）的社会情绪加工过程进行了测量。我们测试了恒河猴是否与人类一样，同样会出现发育转变：从幼年时期的消极偏向（negativity bias，即优先注意消极社会情绪刺激）转变为老年时期的积极偏向（positivity bias）。在第一项实验中，我们通过比较恒河猴（n = 337）注视消极同种信号（威胁展示）照片与匹配中性表情照片的时长，评估了它们对消极社会情绪刺激的反应。与人类观察到的模式相反，我们发现老年恒河猴比幼年恒河猴对消极情绪刺激的关注度更高。在第二项实验中，我们采用相同的方法，对恒河猴（n = 132）注视积极（亲和展示）照片与匹配中性表情照片的注意力情况进行了检测。恒河猴并未表现出对积极刺激的整体偏好，其注意力也未出现显著的年龄相关变化。上述结果表明，尽管恒河猴在社会偏好上表现出显著的个体发育转变，但它们与人类的差异在于：随着年龄增长，其消极偏向会愈发明显。因此，比较认知发育研究能够为人类社会认知发育的进化起源提供洞见。