Ethological Study of Yawning in Primates. I. Quantitative Analysis and Study of Causation in Two Species of Old World Monkeys (Cercocebus albigena and Macaca fascicularis)

Abstract

Yawning is a common, species‐typical behaviour in vertebrates, generally associated with transitions from sleep to wakefulness. In primates, yawning occurs within a group in a variety of social contexts, suggesting that it has a communicative role, a hypothesis examined in this study. Yawning has rarely been studied. Quantitative studies have been concerned only with age, sex and social‐status differences in yawning frequency. The causation and function of yawning were examined in a quantitative, 796‐h ethological analysis of observations of two groups of Cercocebus albigena and one group of Macaca fascicularis. In both species, yawns occurred in two main contexts: during transitions from rest to activity (the ‘rest yawn’) and following social interactions (the ‘emotion yawn’). The rest yawn represents 90 % of yawns and is common to every age‐sex group. By contrast, the emotion yawn (10 %) is more frequent in adult males. Regardless of context, yawning was more frequent in males than females. Within males yawning frequency increased with age. Thus, sex hormones may modulate the physiological processes involved. Yawns were usually performed by individuals in seated, lying or standing positions. Yawns were frequently followed by short periods of rest, so that, when triggered by a social interaction, they occurred at its end. The morphology of the yawning act did not vary in regard to context age and/or sex of the yawner.

Temperature-Dependent Variation in Self-Reported Contagious Yawning

“…Observational research on non-human primates has documented that spontaneous yawning frequency becomes elevated in warm ambient temperatures (Campos and Fedigan 2009;Deputte 1994). Furthermore, experimental studies on birds and rats in the laboratory are consistent with the first two predictions of this model (Gallup et al 2009.…”

Dogs catch human yawns

“…Second, it is also possible that the dogs' yawns may have been induced by mildly heightened tension or stress. For example, macaques are known to exhibit 'emotion yawns' or 'social yawns' during antagonistic social encounters (Deputte 1994;Smith 1999;Paukner & Anderson 2006). Thus, we cannot rule out the possibility that human yawns are perceived as antagonistic to the dogs.…”

An investigation of auditory contagious yawning

“…However, because of the stereotypical head movements associated with the act of yawning (Deputte, 1994;Provine, 1986;Redican, 1975), this question is difficult to directly assess with functional neuroimaging. Nevertheless, there is good reason to believe that the pIFG may be associated with yawning.…”

“…Although what functional or evolutionary advantage that contagious yawning confers is unknown, one popular hypothesis is that it serves as some type of communicative gesture-that is, to synchronize moods in gregarious animals (Deputte, 1994), or to increase vigilance (Daquin, Micallef, & Blin, 2001;Gallup & Gallup, 2007). Certainly, the left pIFG is important for the production of verbal communication signals (Pazzaglia et al, 2008), and the homologous region in the right hemisphere appears to be important for nonverbal acoustic signals (Meyer & Jäncke, 2006).…”