Familiarity modulates both intra- and interspecific yawn contagion in red-capped mangabeys

Abstract

Yawn contagion (YC) is, compared to spontaneous yawning, an evolutionary recent phenomenon probably linked to behavioral synchronization in highly social species that is more likely when it involves familiar subjects. Here, we investigate for the first time in monkeys which factors modulate intra- and interspecific YC. Through an experimental approach, we exposed 17 red-capped mangabeys to video stimuli (Yawn vs Control) depicting familiar/unfamiliar red-capped mangabeys and humans, and unfamiliar hamadryas. We found that mangabeys yawned more often in response to Yawn than Control videos independently from the species depicted, demonstrating both intra- and interspecific YC in the tested species. Moreover, both mangabey and human familiar yawning stimuli evoked a stronger yawning response in the subjects compared to the unfamiliar counterparts. Neither the amount of time spent looking frontally at the screen (probability of stimulus perception) nor the levels of self-directed behaviors (a proxy of anxiety) accounted for the results. In conclusion, we provide the first evidence that in non-human primate familiarity modulates both intra- and inter-specific YC. Stimuli emitted by familiar faces somehow ease the mechanisms underlying YC, and this modulation can also apply to heterospecific subjects when previous shared experiences provide the prerequisites for the development of social bonds.

Interspecific Contagious Yawning in Humans

“…Contagious yawning is well-documented in both naturalistic and experimental studies on humans [ 5 , 24 , 57 , 65 , 77 ], and emerges during early childhood development [ 78 ]. While previous comparative research has provided evidence for interspecific, i.e., human-initiated, contagious yawning in chimpanzees [ 45 , 46 ], red-capped mangabeys [ 47 ], domesticated dogs [ 48 , 50 , 51 , 53 ], and African elephants [ 54 ], to date, there have been no studies examining whether humans yawn contagiously in response to non-human animals.…”

“…Chimpanzees have also been shown to yawn in response to yawns of computer animations of conspecifics [ 29 ], while orangutans do not show this reaction [ 32 ]. A recent paper also found evidence for interspecific yawn contagion among red-capped mangabeys, whereby individuals yawned more in response to conspecifics and familiar human caretakers compared to unfamiliar species (i.e., hamadryas) [ 47 ].…”

“…Whether the variation in this response is driven by social/emotional closeness or enhanced attention towards people we know and care about remains unclear [ 56 ], but the effect is robust. Likewise, many of the studies on interspecific contagious yawning in captive non-human animals have been linked to some degree with empathy and/or social closeness to human owners and handlers [ 46 , 47 , 50 , 51 ]. Therefore, since people tend to form strong bonds and attachments with their pet cats and dogs [ 66 , 67 , 68 ], we also predicted that contagious yawning would be high in the pet condition.…”

The sound of yawns makes geladas yawn

“…Yawning makes you yawn, we have all experienced that. The phenomenon of yawn contagion (YC) is not restricted to humans and seem present mostly in highly social species, across the primate lineage (great apes 1 , cercopithecines 2 – 4 , recently in a south American monkey 5 and in a lemur species 6 ) as well as in species from other orders (e.g., pigs 7 , wolves 8 , domestic dogs 9 , lions, 10 , spotted hyenas 11 , African painted dogs 12 , budgerigars 13 ). Despite the mysteries around the possible functions and neurobiology underpinning YC, recent findings suggest that the phenomenon could have evolved to promote group synchronization 10 and that it correlates to a certain extent with social closeness 14 .…”

Yawning informs behavioural state changing in wild spotted hyaenas

“…The behaviour is also sensitive to the relationship quality shared between interacting subjects: the higher the social closeness, the higher the probability of yawn contagion (Romero et al 2014;Palagi et al 2020;Kret and van Berlo 2021). The positive effect of social closeness on contagion works independently from the species the two interacting subjects belong to (Pedruzzi et al 2022).…”