Auditory Contagious Yawning Is Highest Between Friends and Family Members: Support to the Emotional Bias Hypothesis

Abstract

Contagious yawning differs from spontaneous yawning because it occurs when an individual yawns in response to someone else's yawn. In Homo sapiens and some nonhuman primates contagious yawning is higher between strongly than weakly bonded individuals. Up to date, it is still unclear whether this social asymmetry underlies emotional contagion (a basic form of empathy preferentially involving familiar individuals) as predicted by the Emotional Bias Hypothesis (EBH) or is linked to a top-down, selective visual attention bias (with selective attention being preferentially directed toward familiar faces) as predicted by the Attentional Bias Hypothesis (ABH). To verify whether the visual attentional bias explained the yawn contagion bias or not, in this study, we considered only yawns that could be heard but not seen by potential responders (auditory yawns). Around 294 of auditory yawning occurrences were extrapolated from over 2000 yawning bouts collected in free ranging humans for over nine years. Via GLMM, we tested the effect of intrinsic features (i.e., gender and age) and social bond (from strangers to family members) on yawn. The individual identity of the subjects (trigger and potential responder) was included as random factor. The social bond significantly predicted the occurrence of auditory yawn contagion, which was highest between friends and family members. A gender bias was also observed, with women responding most frequently to others' yawns and men being responded to most frequently by others. These results confirm that social bond is per se one of the main drivers of the differences in yawn contagion rates between individuals in support of the EBH of yawn contagion.

Yawn contagion in domestic pigs (Sus scrofa)

“…Inter-sexual biases in the power of eliciting a yawning response have been found in bonobos, where yawning in group mates can be induced most frequently by females 18 , and in humans (for vocalized yawns perceived only by hearing 31 ) and chimpanzees 30 where males as triggers are particularly effective in triggering others’ yawns. In humans, for vocalized yawns that are heard but not seen, it is possible that men’s vocalizations are better heard than women’s in natural settings, often characterized by background noises 31 . In chimpanzees and bonobos, the sex bias has been related to the dominance or social relevance of the triggering subjects, considering that in chimpanzees males are dominant 30 whereas in bonobos females acquire leadership by forming coalitions 18 .…”

“…In humans and great apes individual features can influence yawn contagion. These features include: (1) age (with the yawning response increasing from the immature period to adulthood; humans 28 ; chimpanzees 29 ; geladas 4 ); (2) sex of the trigger (females can elicit more yawns in bonobos 18 ; males can elicit more yawns in chimpanzees and in humans for yawns that are heard but not seen 30 , 31 ); (3) sex of the responder (with human females showing highest frequencies of response at least under certain conditions 32 ). Moreover, social factors, such as familiarity between trigger and responder, can also affect yawn contagion (humans 33 ; bonobos 18 , 34 ; chimpanzees 17 ; geladas 4 ; wolves 20 ).…”

“…Indeed, in both human and non-human mammals, spontaneous yawning can be linked to physiological and behavioral transitions, such as those occurring over the sleep-wake cycle or during the transitions around emotional arousal (humans, Homo sapiens 24 ; South American sea lions, Otaria flavescens 25 ; Verreaux' sifaka, Propithecus verreauxi and ring-tailed lemurs 26 ; rats, Rattus norvegicus 27 ).In humans and great apes individual features can influence yawn contagion. These features include: (1) age (with the yawning response increasing from the immature period to adulthood; humans 28 ; chimpanzees 29 ; geladas 4 ); (2) sex of the trigger (females can elicit more yawns in bonobos 18 ; males can elicit more yawns in chimpanzees and in humans for yawns that are heard but not seen 30,31 ); (3) sex of the responder (with human females showing highest frequencies of response at least under certain conditions 32 ). Moreover, social factors, such as familiarity between trigger and responder, can also affect yawn contagion (humans 33 ; bonobos 18,34 ; chimpanzees 17 ; geladas 4 ; wolves 20 ).…”

“…No yawn was vocalized (via vocal folds). The possible yawning response was collected in blocks of three minutes, used in previous studies 15,18,33 , to reduce autocorrelation probability 31,47 . For each yawn, we recorded the identity of the yawner (trigger) and the identity of the animals present on videos (hereafter potential responders).…”

Patterns of Contagious Yawning and Itching Differ Amongst Adults With Autistic Traits vs. Psychopathic Traits

“…For example, susceptibility to contagious yawning is positively related to performance on cognitive empathy measures, such as Theory of mind tasks, and negatively related to schizotypal traits (Platek et al, 2003). In addition, contagious yawning tends to be greatest in response to kin, then friends, then acquaintances, and lastly strangers (Norscia and Palagi, 2011;Norscia et al, 2020)a pattern consistent with other empathic behaviors (Preston andde-Waal, 2002, although Massen et al, 2015, reported that participants were no more likely to yawn contagiously to a member of their political "in" vs. "out" group). Furthermore, contagious yawning is not present in infants or toddlers (Helt et al, 2010) but rather develops during the preschool years (Cordoni et al, 2021) along the same timeline as other empathic abilities (Perner and Lang, 1999).…”