Page 114 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Chapter 5
Abstract
Primates show various forms of mimicry that are stronger between kin and friends. As a result, mimicry is thought to promote group coordination, social cohesion, and possibly state matching (or: emotion contagion). Aside from contagious yawning, little is known about the contagious effect of other behaviors. Self-scratching is commonly observed during arousal and as such may play a role within group dynamics. While the Bornean orangutan (Pongo pygmaeus) is commonly considered the least social great ape, orangutans do engage in social interactions. Therefore, their social organization makes them a suitable case for studying the social function of mimicry. Through behavioral observations of captive orangutans, we recorded all yawn and self-scratch events together with the corresponding behavior of all bystander group‐members. As yawning was rarely observed, no conclusions could be drawn regarding this behavior. Self-scratching was contagious and occurred within 90 s after the triggering self-scratch. Specifically, orangutans showed increased self-scratch contagion when they had seen a weakly bonded individual self-scratch during tense contexts. When the orangutan had not seen the triggering self-scratch, the contagiousness of self-scratching was not affected by context or relationship quality. Our results indicate that mimicry is not simply higher between individuals with stronger social relationships, but that the contagiousness of behaviors may vary based on the context and on social factors. We discuss these findings in light of an adaptive function that may reduce aggression.
Based on:
Laméris, D. W., Van Berlo, E., Sterck, E. H. M., Bionda, T., & Kret, M. E. (2020). Low relationship quality predicts scratch contagion during tense situations in orangutans (Pongo pygmaeus). American Journal of Primatology, 82, e23138. https://doi. org/10.1002/ajp.23138
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