Low relationship quality predicts scratch contagion during tense situations in orangutans (Pongo pygmaeus).

Daan W Laméris,Mariska E Kret,Evy Van Berlo,Thomas Bionda,Elisabeth H M Sterck

doi:10.1002/ajp.23138

Daan W Laméris, Mariska E Kret + Show 3 more

Open Access

https://doi.org/10.1002/ajp.23138

Copy DOI

Abstract

Primates show various forms of behavioral contagion that are stronger between kin and friends. As a result, behavioral contagion is thought to promote group coordination, social cohesion, and possibly state matching. Aside from contagious yawning, little is known about the contagious effect of other behaviors. 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 behavioral contagion. Through behavioral observations of captive orangutans, we recorded all yawn and 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. Scratching was contagious and occurred within 90 s after the triggering scratch. Specifically, orangutans showed increased scratch contagion when they had seen a weakly bonded individual scratch during tense contexts. When the orangutan had not seen the triggering scratch, the contagiousness of scratching was not affected by context or relationship quality. Our results indicate that behavioral contagion 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.

Highlights

Behavioral contagion is a phenomenon in which a behavior is automatically triggered by the perception of a similar behavior in others (Zentall, 2003)
When only considering the cases where the observer had seen the triggering scratch, we found that scratching is more contagious between individuals that shared a low relationship quality during tense contexts compared with relaxed contexts (z = 2.301, p = .021) and during tense context between individuals that shared a low relationship quality compared with a high relationship quality (z = 2.348, p = .019)
The current study aimed to investigate whether yawning and scratching are contagious in the orangutan and whether the contagion of these behaviors is linked to the context in which these behaviours occur and the quality of the bond between individuals

Summary

| INTRODUCTION

Behavioral contagion is a phenomenon in which a behavior is automatically triggered by the perception of a similar behavior in others (Zentall, 2003). The recognition and acquisition of the emotions of aroused individuals can result in fewer costly interactions (Whitehouse, Micheletta, Kaminski, & Waller, 2016) While these studies suggest that scratching may play an important role within social groups, the contagious effect of scratching and its potential function is poorly understood. Based on a previous study reporting the presence of rapid facial mimicry (Davila Ross et al, 2008), we hypothesize that behavioral contagion is present and extends to yawning and scratching behavior If these behaviors have a social function, we expect that the contagion of yawning and scratching will be influenced by the relationship quality of the expresser and observer and that contagion is higher between kin and friends

| METHODS

Findings

| DISCUSSION