Le bâillement, du réflexe à la pathologie
Le bâillement : de l'éthologie à la médecine clinique
Le bâillement : phylogenèse, éthologie, nosogénie
 Le bâillement : un comportement universel
La parakinésie brachiale oscitante
Yawning: its cycle, its role
Warum gähnen wir ?
 
Fetal yawning assessed by 3D and 4D sonography
Le bâillement foetal
Le bâillement, du réflexe à la pathologie
Le bâillement : de l'éthologie à la médecine clinique
Le bâillement : phylogenèse, éthologie, nosogénie
 Le bâillement : un comportement universel
La parakinésie brachiale oscitante
Yawning: its cycle, its role
Warum gähnen wir ?
 
Fetal yawning assessed by 3D and 4D sonography
Le bâillement foetal
http://www.baillement.com

mystery of yawning 

 

 

mise à jour du
28 mars 2019
Journal of Experimental Psychology
2018;147(12):1950-1958.
Contagious Yawning, Empathy
and Their Relation to Prosocial Behavior  
Axel Franzen and Sebastian Mader
University of Bern  
Fabian Winter
Max Planck Institute for Research on Collective Goods, Bonn, Germany

Chat-logomini

 Tous les articles sur la contagion du bâillement
All articles about contagious yawning
 
Abstract
Humans express facial mimicry across a variety of actions. This article explores a distinct example, contagious yawning, and the links to empathy and prosocial behavior. Prior studies have suggested that there is a positive link between empathy and the susceptibility to contagious yawning. However, the existing evidence has been sparse and contradictory. The authors present results from 2 laboratory studies conducted with 171 (Study 1) and 333 (Study 2) student volunteers. Subjects were video-recorded while watching muted videos of individuals yawning, scratching, or laughing. Empathy was measured using the Interpersonal Reactivity Index. Although subjects imitated all facial expressions to large extents, their studies show that only contagious yawning was related to empathy. Subjects who yawned in response to observing others yawn exhibited higher empathy values by half a standard deviation. However, they found no evidence that the susceptibility to contagious yawning is directly related to prosocial behavior.
 
Résumé
Les humains extériorisent leurs capacités mimétiques des expressions du visage de nombreuses façons. Cet article explore un exemple, la contagion du bâillement, et explore ses liens avec l'empathie et tente de déterminer sa nature de comportement prosocial. Des études antérieures ont suggéré qu'il existe un lien positif entre l'empathie et la susceptibilité à la réplication du bâillement. Cependant, les preuves existantes sont peu nombreuses et certaines contradictoires. Les auteurs présentent les résultats de deux études de laboratoire menées auprès de 171 étudiants volontaires (étude 1) et 333 (étude 2). Les sujets ont été enregistrés par vidéo tout en regardant des vidéos d'individus bâillant, se grattant ou riant. L'empathie a été mesurée à l'aide de l'indice de réactivité interpersonnelle. Bien que les sujets aient imité toutes les expressions faciales, ces études montrent que seul le bâillement contagieux est lié à l'empathie. Les sujets qui bâillent en observant les autres bâiller manifestent des valeurs d'empathie supérieures d'un demi-écart-type. Cependant, ils n'ont trouvé aucune preuve que la susceptibilité au bâillement soit directement liée au comportement prosocial.

Humans are social beings. They are highly skilled in interpreting the facial expressions and gestures of other humans and in re- sponding to the signals, expectations, and behaviors encoded in these actions. Some forms of emotional and behavioral imitation appear unconsciously and within milliseconds (e.g., Chartrand & Bargh, 1999; Dimberg, Thunberg, & Elmehed, 2000). Other reac- tions are more conscious and context-dependent (see Hess & Fischer, 2013, for a recent review). Both strands of the literature have suggested that mimicry, be it conscious or unconscious, facilitates social cohesion and coordination in groups (e.g., Lakin, Jefferis, Cheng, & Chartrand, 2003). The existing evidence has suggested that mimicry works in two ways: First, the mimickee infers from the imitation of his behavior or gestures that others understand his intentions or emotions. Second, the mimicker en- hances his empathy with the person he imitates. Thus, Stel, Van Baaren, and Vonk (2008) showed that subjects who were in- structed to mimic others also have higher levels of empathy for the imitated person. Hence, mimicking others can elevate empathy, which in turn increases prosocial behavior even toward others not related to the mimicking.
 
Also, the relation between empathy and prosocial behavior has been much discussed in the literature (Batson, 1991; Batson & Moran, 1999; de Waal, 2012; Eisenberg & Miller, 1987; Galinsky, Maddux, Gilin, & White, 2008; Stocks, Lishner, & Decker, 2009). Some authors have suggested that empathy is an unpleasant emo- tion (e.g. Batson, 1991). One way of reducing it is to either escape situations in which empathy emerges or help those in need. This hypothesis has been termed the aversivearousal reduction hy- pothesis (Batson, 1991). According to the hypothesis, prosocial behavior is basically a selfish response. An alternative mechanism is that empathy highlights an altruistic perspective. So far, most evidence has supported this empathyaltruism hypothesis (Doris & Stitch, 2007; Nichols, 2004; Stocks et al., 2009). In this article, we focus on a distinct and peculiar phenom- enon of mimicry, namely the contagiousness of yawning. Hu- mans, like most vertebrates, yawn occasionally.
 
The existing evidence has suggested that it is induced by sleepiness (e.g. Provine, 2005). Yawning increases the oxygen content of the blood and lowers the brain temperature, functioning as a wake-up call (Gallup & Gallup, 2007, 2008; Guggisberg, Ma- this, Schnider, & Hess, 2011; Provine, 2005; Zilli, Giganti, & Uga, 2008). However, yawning can also be contagious. Former studies have suggested that about 40% to 60% of humans are susceptible to contagious yawning (e.g., Gallup, Church, Miller, Risko, & Kingstone, 2016), and there is also evidence that it is contagious among some animals, like chimpanzees, dogs, and wolves (e.g., Romero, Ito, Saito, & Hasegawa, 2014; Romero, Konno, & Hasegawa, 2013). Moreover, some studies have suggested that the susceptibility of contagious yawning is linked to the degree of empathy (Lehmann, 1979; Norscia et al., 2016b; Palagi, Leone, Mancini, & Ferrari, 2009; Provine, 1986, 2005). For instance, Platek, Critton, Myers, and Gallup (2003) found that individuals who are more sensitive to contagious yawning also recognize social faux pas in written reports better than do subjects who are not susceptible to it. Yawning is also more contagious among individuals with close social ties, compared to strangers (Nors- cia, Demuru, & Palagi, 2016b; Norscia & Palagi, 2011; Palagi, Norscia, & Demuru, 2014). Moreover, Haker and Rössler (2009) found that individuals with schizophrenic disorders are less sensitive to contagious yawning and also display lower empathy values compared to healthy individuals.
 
Further evidence stems from studies in neuroscience that use functional magnetic resonance imaging. These results suggest that the urge to yawn when observing others yawning is related to neural activity in those areas of the brain that are involved in assessing self-referent information (Arnott, Singhal, & Goodale, 2009; Brown et al., 2017; Cooper et al., 2012; Haker, Kawohl, Her- wig, & Rössler, 2013; Platek, Mohamed, & Gallup, 2005). To sum up, research so far has suggested that asking indi- viduals to imitate others elevates their empathy and that empa- thy in turn increases prosocial behavior. In this article we investigate a slightly different question. We study the link of contagious yawning and empathy if researchers do not actively encourage the mimicry. Hence, we investigate whether the susceptibility of contagious yawning is also an indicator of individuals' baseline empathy level. Some existing evidence on contagious yawning has suggested this link. However, other studies have shown counterevidence.
 
Particularly, a study by Bartholomew and Cirulli (2014) using 328 subjects found no evidence that contagious yawning is related to empathy. Be- sides its comparatively large sample, the study by Bartholomew and Cirulli has the advantage of measuring empathy directly via the Interpersonal Reactivity Index (IRI), whereas studies reporting positive evidence relied on indirect measures such as the faux-pas test or the auxiliary assumption that empathy is higher among closer social ties. But Bartholomew and Cirulli's (2014) study also has some disadvantages. First, subjects had to self-report whether they yawned. Measuring yawning by self-report has the disadvan- tage of leaving the measurement to the subjects and their interpretation and thus withdraws it from the control of the experimenter. Second, the experimenters informed subjects of the phenomenon of contagious yawning before they partici- pated in the study, which may have stimulated the social desir- ability of contagious yawning. Yawning was reported by 67% of their subjects, which is a higher incidence of yawning than reported in other studies. The high incidence could have obscured the difference between yawners and nonyawners with respect to empathy. Furthermore, Bartholomew and Cirulli did not use any control group in their study. Therefore, it remains unclear what the rate of yawning would have been if subjects had watched other stimulus videos of nonyawning faces. This makes the distinction between yawning that occurs spontane- ously and yawning that occurs due to contagion impossible.
 
Taken together, the empirical evidence on whether conta- gious yawning is related to empathy is still unclear, and the existing evidence contradictory (e.g., Massen & Gallup, 2017). Studies that found positive evidence did not employ direct measurements of empathy (e.g., by using the IRI), and the study that found no evidence (Bartholomew & Cirulli, 2014) used a weak measure of the occurrence of contagious yawning. To gain further insight into the phenomenon of contagious yawning and its relation to empathy, we conducted two studies with large samples of healthy volunteers. Study 1 was conducted in a manner very similar to that in the Bartholomew and Cirulli (2014) study. However, we videotaped subjects while they were watching the stimulus videos and coded the occurrence of yawning from these videos. Because prior studies have pro- posed that empathy is an important prerequisite of altruism and prosocial behavior (Batson & Moran, 1999; de Waal, 2012; de Waal & Preston, 2017; Eisenberg & Miller, 1987; Galinsky et al., 2008; Stocks et al., 2009), we extend the existing literature on contagious yawning by also investigating whether it is directly related to prosocial behavior.
 
In Study 1, the test consisted of a dictator game in which subjects had the oppor- tunity to donate some (or all) of their endowment to an anonymous recipient. Because Study 1 also did not involve a control group, we conducted a second study, in which subjects were randomized into either a treatment group or a control group. In the treatment group, subjects watched videos of laughing faces, people scratching or touching their face or hair, and yawning faces. In the control group, subjects watched only laughing and scratching subjects. This experimental procedure allowed us to determine the natural occurrence of spontaneous yawning in comparison to contagious yawning. Moreover, it also allowed us to test whether other forms of mimicry (scratching and laughing) are related to empathy.
 
We also measured prosocial behavior in Study 2 by giving subjects the opportunity to donate some (or all) of their experimental payment to a charitable organization. Summing up, we investigated three hypotheses: Hypothesis A postulates that empathy is positively related to prosocial behavior. Hypothesis B suggests that empathy varies among individuals and that the susceptibility of contagious yawning is an indicator of empathy. Hypothesis C suggests that those who show contagious yawning also more likely show prosocial behavior. The remainder of the article proceeds in as follows: First, we describe the method used in Study 1, followed by the results. Then we discuss the limitations of Study 1 and describe the method used in Study 2, which responds to the limitations of Study 1 and extends the existing evidence. Specifically, Study 2 investigates whether other forms of facial mimicry are also indicators of empathy. Then we report the results of Study 2. Finally, the results of both studies are summarized and discussed.
 
 
Discussion
This study found clear evidence that susceptibility to contagious yawning is related to empathy. In Study 1, 24% of the subjects yawned, and yawning subjects showed higher empathy values by .49 standard deviation when compared to nonyawning subjects. This result was closely replicated in Study 2, in which 22% of the subjects yawned in response to the stimulus video. Our finding confirms results of previous research, which showed indirect evi- dence of yawning's being related to empathy (Arnott et al., 2009; Norscia et al., 2016b; Norscia & Palagi, 2011; Palagi et al., 2014; Platek et al., 2003, 2005), and disconfirms the missing evidence reported by Bartholomew and Cirulli (2014). We believe that the association between contagious yawning and empathy was ob- scured in the Bartholomew and Cirulli study for methodological reasons. The authors informed subjects beforehand about the nature of contagious yawning, and they relied on the subjects' self-reporting to measure the occurrence of yawning.
 
In contrast, we recorded the subjects on video and thus have a more objective and reliable measure of the occurrence of yawning. The contagion rate of 24% that we found is comparatively low. One reason for this might be that subjects watched the stimulus videos while other subjects were also present in the laboratory. All workplaces were separated by cubicles in such a way that subjects' faces were not directly observable by other subjects. However, the mere presence of others in the same room might have inhibited contagious yawning, as suggested by Gallup et al. (2016). Furthermore, Study 2 shows that other mimicry, for example, face scratching or laughing, is not an indicator of empathy. This finding is not in contradiction with the results of Stel et al. (2008), who instructed subjects to imitate others and found elevated em- pathy levels afterward. But our results suggest that the simple occurrence of a smile while watching others smile or laugh is not an indicator of empathy, as is contagious yawning. Taken together, these results suggest that contagious yawning is a special and distinct phenomenon. It is hard to control and seems to be biolog- ically ingrained in highly social species, such as monkeys, apes, and humans. Highly social species must often rely on the synchro- nization of behavior, particularly in situations of escaping from predators, coordinating sleepwake cycles, or adhering to social norms. Hence, it might have been evolutionarily advantageous to be highly susceptible to the emotions and intentions of others, and authors like de Waal (2008) have suggested that empathy provides the basis for synchronized motor action and synchronizes emo- tional states. This, in turn, has positive feedback effects on social cohesion (Palagi et al., 2009; Seyfarth & Cheney, 2013) and promotes helping behavior and identification with conspecifics (Preston & de Waal, 2002).
 
Our study found positive evidence for only Hypotheses A and B and not for Hypothesis C, that contagious yawning has a direct link to prosocial behavior. Yawning subjects did donate more money to an anonymous recipient in the dictator game (Study 1). However, the difference between yawners and nonyawners was not statisti- cally significant. The same results held true with respect to donat- ing to a charitable organization (Study 2). Hence, contagious yawning is a signal of empathy, but the signal is not very strong or clear. However, using a measure of general empathy and general prosocial behavior (as we did) does not take context into consid- eration. The relation between contagious yawning and prosocial behavior might indeed be stronger if the prosocial behavior is specific and directed toward members of one's own group.
Moreover, the degree of empathy is also determined by other factors such as gender (as also shown by our results) or presum- ably through education and socialization (not tested here). Norscia et al. (2016b) and Chan and Tseng (2017) reported that female subjects were more susceptible to contagious yawning. Also, in our studies, women were more susceptible to contagious yawning (24.4%) than were men (19.6%). However, this difference is not statistically significant, 2(1, N 354) .97, p .32, confirming the results of various other studies (e.g., Gallup & Massen, 2016). However, the IRI shows clearly higher values for women. Hence, we also conclude that women are more empathetic than are men, presumably because women are "hard-wired for maternity and parental care" (Norscia et al., 2016b, p. 1; for a detailed discussion of the gender effect, see also Norscia, Demuru, & Palagi, 2016a).
 
It is interesting that, and not easily explained why, only conta- gious yawning, and not scratching or laughing, was related to empathy in our study. One interpretation is that scratching, and more so laughing, are more easily controllable behaviors. Individ- uals might have learned that it is socially expected to imitate a smile or laugh. However, yawning is much harder to control or to suppress, and it is therefore harder to be shaped by cultural factors. We believe that the study results represent an important finding and indicate avenues for further research. First, susceptibility to contagious yawning seems to be an implicit test of empathy. Second, the finding that contagious yawning is not generally related to prosocial behavior raises questions about whether this association can be found in groups of closer social ties (e.g., as parochial prosocial behavior) along the lines suggested by De Dreu et al. (2010).