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
14 décembre 2021
Sci Rep
2021 Dec 10;11(1):23779
People that score high on psychopathic traits
are less likely to yawn contagiously
Gallup AC, Kret ME, Eldakar OT, Folz J, Massen JJM.

Chat-logomini

Abstract
Considerable variation exists in the contagiousness of yawning, and numerous studies have been conducted to investigate the proximate mechanisms involved in this response. Yet, findings within the psychological literature are mixed, with many studies conducted on relatively small and homogeneous samples. Here, the authors aimed to replicate and extend upon research suggesting a negative relationship between psychopathic traits and yawn contagion in community samples. In the largest study of contagious yawning to date (N_=_458), which included both university students and community members from across 50 nationalities, participants completed an online study in which they self-reported on their yawn contagion to a video stimulus and completed four measures of psychopathy: the primary and secondary psychopathy scales from the Levenson Self-Report Psychopathy Scale (LSRPS), the psychopathy construct from the Dirty Dozen, and the Psychopathic Personality Traits Scale (PPTS). Results support previous findings in that participants that yawned contagiously tended to score lower on the combined and primary measures of psychopathy. That said, tiredness was the strongest predictor across all models. These findings align with functional accounts of spontaneous and contagious yawning and a generalized impairment in overall patterns of behavioral contagion and biobehavioral synchrony among people high in psychopathic traits.
 
Résumé
Il existe des variations considérables de la contagiosité du bâillement, et de nombreuses études ont été menées pour étudier les mécanismes immédiats impliqués dans cette réponse. Pourtant, les résultats de la littérature psychologique demeurent confus, après de nombreuses études menées sur des échantillons relativement petits et homogènes. Ici, les auteurs ont cherché à reproduire et à étendre les recherches suggérant une relation négative entre les traits psychopathiques et la contagion du bâillement. Dans la plus grande étude sur la contagion du bâillement à ce jour (N_=_458), qui comprenait à la fois des étudiants d'universités et un public de 50 nationalités différentes, les participants ont complété une étude en ligne dans laquelle ils ont autodéclaré leur contagion du bâillement à un stimulus vidéo et ont complété quatre mesures de la psychopathie : les échelles de psychopathie primaire et secondaire de l'échelle de psychopathie d'auto-évaluation de Levenson (LSRPS), la construction de psychopathie de la Dirty Dozen et l'échelle des traits de personnalité psychopathiques (PPTS). Les résultats corroborent les conclusions précédentes selon lesquelles les participants qui bâillaient de manière contagieuse avaient tendance à obtenir des scores inférieurs aux mesures combinées et primaires de la psychopathie. Cela dit, la fatigue était le prédicteur le plus fort dans tous les modèles. Ces résultats correspondent aux critères des bâillements spontanés et contagieux et à une réduction de la sensibilité à la contagion comportementale et de la synchronie bio-comportementale chez les personnes présentant des traits psychopathiques élevés.
 
Tous les articles d'Andrew Gallup
Tous les articles sur la contagion du bâillement
All articles about contagious yawning
 
Introduction
The automatic and reflexive tendency to yawn in response to sensing the yawns of others, i.e., contagious yawning, is well-documented in humans1,2, and has been observed in a growing number of non-human species including non-human great apes3,4, dogs5, pigs6, and birds7,8, among others. Unlike spontaneous yawning, which begins in utero9, is ubiquitous across vertebrates10, and appears to be a human universal11, contagious yawning does not emerge until early childhood12,13, is limited to social species14, and psychological studies reveal considerable variability in the tendency for people to yawn contagiously. In particular, the percentage of participants that yawn in response to video and/or audio stimuli of others yawning typically ranges between 30 and 60% (e.g.1,2,15,16,17,18,19).
 
This variability in yawn contagion has drawn considerable attention over the last two decades (e.g.2,20,21), with numerous published works examining factors that contribute to this response. Overall, the primary emphasis of research in this area has been to explore associations between contagious yawning and empathy or emotional contagion (reviewed by22,23). The proposed link between contagious yawning and empathic processing originates from a monograph by Lehmann24, and has been elaborated more recently in its inclusion in the Perception&endash;Action-Model (PAM) proposed by Preston and de Waal25,26. Accordingly, the motor mimicry of yawn contagion results from a perception&endash;action mechanism that permits the rapid synchronization of states between individuals27. Extending from the PAM, contagious yawning has been proposed to represent a basic form of emotional contagion, whereby the yawns, and accompanied emotional or mental state of the yawner, are passed on to another individual22. Similarly, automatic facial mimicry is hypothesized to enhance emotional recognition28, and has been considered to be a critical feature of emotional contagion29. While the motor action pattern of yawning is clearly contagious, as referenced by works above, this theory lacks empirical evidence when it comes to the transfer of emotional states during yawn contagion23. Moreover, in general, the role of facial mimicry in the transfer of emotional states is not unequivocal30. Therefore, this phenomenon might be better explained by simple behavioral contagion or facial mimicry31,32,33. In contrast to emotional contagion, whereby the synchrony of behaviors and emotions are neurologically linked, simple behavioral contagion represents the copying of the behavior itself. Yawn contagion could be adaptive in the absence of emotional coupling in facilitating collective vigilance and coordinated group behavior23. Nonetheless, the idea that contagious yawning is perhaps reflective of empathy or emotional contagion has drawn considerable interest and investigation.
 
Platek et al.2 garnered initial support for a connection between contagious yawning and mental state attribution (a form of cognitive empathy) among samples of university students. These authors found that contagious yawning was positively correlated with performance on self-face recognition and faux pas theory of mind tests, and negatively correlated with measures of schizotypal personality traits. Since then, psychological studies examining associations between individual differences on empathy measures and yawn contagion have revealed mixed findings (e.g.20,21,34,35,36), with most studies reporting no clear relationship (reviewed by23). For example, in what was the largest study at the time (N_=_328), Bartholomew and Cirulli20 found highly consistent individual differences in yawn contagion to video stimuli in an online format, but when accounting for the age of the participants, yawn contagion was not related to empathy as measured by the Interpersonal Reactivity Index (IRI)37. More recently, however, Franzen et al.21 conducted two large laboratory studies (N_=_171; N_=_333) and found that participants who yawned contagiously reported significantly higher empathy levels as measured by the IRI. Yet, in a smaller study (N_=_97) published recently, contagious yawning was unrelated to the total IRI score, or any of the subscales (cognitive: perspective taking and fantasy; affective: empathic concern and personal distress)19. In sum, results from studies linking individual differences in yawn contagion to measures of empathy remain inconsistent.
 
As an indirect measure of empathy, studies have also examined ingroup or familiarity biases in yawn contagion. Observational studies suggest that naturalistic instances of yawn contagion appear to occur more regularly among friends and family compared to acquaintances and strangers38,39. Yet, enhanced attention towards familiar individuals and the tendency to avoid the gaze of strangers or less familiar acquaintances, could have contributed to this effect40. To date, the only experimental research to examine in-group or familiarity biases in yawn contagion among humans failed to show an effect41. Researchers have also explored gender differences in yawn contagion, as there are marked differences in empathy between men and women42. In support of this notion, Norscia and colleagues43 reanalyzed data from the aforementioned observational study38 and found that women yawned contagiously more so than men. These authors have also noted a similar effect for auditory yawn contagion39. However, an analysis across the broader literature demonstrated no differences in contagious yawning between men and women44.
 
Another approach to assessing the link between contagious yawning and empathy has been to study clinical populations with deficits in empathy and to assess variability in other psychological attributes predictive of empathic processing in non-clinical populations. This area of research has led to the examination of (1) group differences in contagious yawning among children with autism spectrum disorder (ASD), and (2) correlational studies measuring individual differences in psychopathic traits and the susceptibility to yawn contagiously. Individuals with ASD tend to be characterized by impairments in cognitive empathy or perspective taking (i.e., theory of mind), while psychopathic traits are associated with reduced affective empathy, including diminished primary emotions such as fear and sadness45. Interestingly, both ASD and the prevalence of psychopathic traits are more common among males46,47. These populations are also of interest to study with regards to the hypothesized functional significance of yawn contagion in promoting collective vigilance and synchronized group behavior/movement48,49,50,51,52,53. Impairments in imitation and joint attention among individuals with ASD diminish cooperation and coordinated actions54. Individuals with ASD also show diminished facial mimicry55,56 and less synchronization during interpersonal coordination57. Similarly, psychopathy is marked by deceit and a lack of cooperation58, and individuals that score high on callous-unemotional traits also display reduced facial mimicry30,59 and diminished group cohesion60. In addition, a general impairment in biobehavioral synchrony has been implicated in psychopathy61.
 
The first such study on contagious yawning involving individuals with ASD was conducted by Senju et al.62. Using standard laboratory procedures, i.e., the presentation of video stimuli with people yawning, children with ASD showed diminished yawn contagion&emdash;an effect that garnered significant interest in the scientific community and was subsequently replicated by Giganti and Ziello63 and Helt and colleagues64. While initially taken as strong support for a link between contagious yawning and empathy, further work refined this view showing that the diminished contagion among children with ASD results from reduced attention to yawning stimuli. When instructed to focus their attention on the eyes of the yawning target in the stimuli, individuals with ASD displayed rates of contagious yawning equivalent to aged-matched control samples (e.g.18,65). Moreover, when using eye-tracking to confirm that visual attention is allocated to the stimuli during testing, both typically developing children and those with ASD yawn more often to depictions of yawning than to control clips66. In another study, Mariscal et al.67 measured contagious yawning along with blood oxytocin levels from both children with ASD and those that were typically developing. Again, no group differences in yawn contagion were found, i.e., children with ASD yawned just as often as typically developing children. However, a positive relationship was reported between contagious yawning and oxytocin among children with ASD, while no such relationship was present in the control group. Although links between contagious yawning and oxytocin continue to be discussed68, attempts to experimentally manipulate oxytocin through intranasal administration have found no effect on yawn contagion69,70.
 
To date, only two studies have examined the link between contagious yawning and psychopathic traits. Rundle, Vaughn, and Stanford71 had university students (N_=_135) from the United States complete the Psychopathic Personality Inventory-Revised (PPI-R)72 and watch a series of yawning videos to obtain physiologically defined measures of yawn contagion using facial electromyography and galvanic skin response. When comparing participants that did and did not yawn, there was no difference in overall scores on the PPI-R. However, when examining the individual subscales of the PPI-R, which include fearless dominance, self-centered impulsivity, and cold-heartedness, the latter predicted yawn contagion. That is, participants who scored higher on measures of cold-heartedness were less likely to yawn contagiously. Males from the sample (N_=_57) also took part in an eyeblink startle paradigm, and consistent with a link to psychopathy, contagious yawning was less common in men with a lower startle response71. The negative association between contagious yawning and psychopathic traits was also recently examined by Helt et al.19. Drawing from a slightly smaller sample of university students in (N_=_97) also from the United States, participants completed the PPI-R, the Autism Spectrum Quotient (AQ), and the IRI (see above). Unlike Rundle et al.71, a negative relationship was revealed between the combined PPI-R and video confirmed yawn contagion (yes/no), i.e., participants that scored higher on psychopathic traits were less likely to yawn contagiously, though no analyses were conducted across the subscales of this measure. By employing eye-tracking, the researchers were also able to show that the negative relationship between contagious yawning and scores on the PPI-R was not moderated by visual attention. A similar negative relationship was found between the AQ and contagious yawning, but unlike measures of psychopathy, the relationship between yawn contagion and the AQ was moderated by eye gaze19. Lastly, contagious yawning was not significantly correlated with total empathy or any of the subscales of the IRI.
 
Based on the overall mixed findings within the psychological literature, and the relatively limited investigation into the link between psychopathic traits and yawn contagion in particular, the current study aimed to provide resolution to this anticipated association. In particular, this investigation sought to replicate and extend upon the findings from Rundle et al.71 and Helt et al.19, but with a larger and more heterogeneous sample of online participants. Four distinct measures of psychopathy were included to assess the generalizability of this association, and given the importance of physiological variables in influencing yawn contagion (e.g.15,48,73,74,75,76,77,78), measures of sleep and fatigue were taken into consideration. Lastly, given recent debates on the importance of attention in contributing to yawn contagion22,23,34,65, both objective and subjective measures of attention to the contagious yawning video stimulus were included.
 
 
Discussion
In a large-scale conceptual replication of two previous publications19,71, the findings from this study demonstrate a small, but significant negative relationship between yawn contagion and psychopathic traits in a community sample. While these previous studies included a single measure of psychopathy (PPI-R) among university student populations in the United States, the current study assessed the generalizability of this relationship across different scales in a much larger and more heterogenous sample. Consistent with previous reports, we show that participants who failed to show contagious yawning (37.3%) tended to score higher on various measures of psychopathy, including the primary psychopathy scale of the LSRPS79, the psychopathy construct of the Dirty Dozen80, and the combined PPTS81. However, the effect sizes from these comparisons were small (Rank biserial correlations_=_0.126&endash;0.141). When considering participant gender, age, prior sleep, current tiredness, and objective and subjective measures of attention, only the primary psychopathy scale of the LSRPS and the combined PPTS remained significant, with tiredness of participants serving as the best predictor of yawn contagion across all models. Consistent with a previous review of the literature44, and replicating the findings of Rundle et al.71, we show no difference in contagious yawning between men and women.
 
Given that psychopathy is characterized by deficits in emotional empathy, or the ability to be affected by&emdash;or share&emdash;the emotional states of others45, the impetus for examining the connection between psychopathic traits and contagious yawning has focused on purported links between contagious yawning and empathy19,71. In particular, Rundle et al.71 found that scores on the social-emotional component of the PPR-I, i.e., cold-heartedness, negatively predicted yawn contagion. Since cold-heartedness represents the inconsideration of the emotional state of others72, this result was consistent with the notion that contagious yawning represents a basic form of emotional contagion22,24,25,26. In line this view, Helt et al.19 found an inverse relationship between combined PPR-I scores and yawn contagion, and that the overall measure of psychopathy was negatively correlated with personal distress in social interactions. Based on these findings, the authors proposed that callous and unemotional traits producing less personal distress might contribute to the inability to achieve bodily resonance with others, and that diminished yawn contagion is due to a malfunctioning of the empathic system.
 
With regards to the current study, the primary psychopathy scale of the LSRPS&emdash;which was the best predictor of contagious yawning from all psychopathy measures&emdash;captures indices of individual callousness, egocentricity, manipulation, selfishness, and deceit79, and is thus in line with these previous reports. The four questions within the psychopathy construct of the Dirty Dozen measure these dimensions as well80, and individuals that scored higher on this instrument were also less likely to yawn contagiously. In addition, the results revealed a significant negative relationship to the combined PPTS, which also emphasizes primary psychopathic personality characteristics81. Low internal consistency precluded the assessment of the affective responsiveness subscale of the PPTS, which is most closely related to the cold-heartedness subfactor of the PPI-R found to be significant in Rundle et al.71. However, the results did reveal a significant negative relationship to the combined PPTS. The secondary psychopathy measure of the LSRPS was the only instrument unrelated to yawn contagion. Unlike the other measures, secondary psychopathy is associated with antisociality, anxiety-driven impulsivity, and irresponsibility, and reflects more of an antisocial-behavioral dimension of psychopathy82. In particular, the PPTS was designed with the intention to place a greater emphasis on personality rather than behavior81. Thus, yawn contagion appears to be largely associated with affective-interpersonal personality characteristics.
 
These findings are consistent with the view that contagious yawning is associated with empathy or emotional contagion22. In line with this perspective, and as it relates to the current findings, prior works have shown that adolescent males that score high on callous-unemotional traits both score lower on self-report empathy and have reduced facial mimicry, as measured by electromyography, to empathy-inducing video clips59 and dynamic emotional expressions30. However, it is important to acknowledge that psychopathic traits only represent an indirect measure of empathy, such that yawn contagion could merely reflect a simple feature of behavioral contagion or facial mimicry31,32,33. While empathy represents a superordinate category of PAM25,26, features explained by this model, and subclasses of phenomena with the same mechanism, such as imitation and state matching, do not require empathy. This is similar to the Russian-doll model for the evolution of empathy, whereby components of empathy are layered on top of and dependent upon one another27. In this case, motor mimicry is at the core within a perception&endash;action mechanism, but in and of itself does not reflect empathy.
 
Therefore, as an alternative interpretation, the characteristic features of psychopathy might represent an impairment in attachment, social affiliative behaviors, and social connectedness that affects more general features of behavioral contagion61. Consistent with the view, Helt et al.19 found a similar negative relationship between psychopathic traits and itch contagion, which is not implicated in empathic processing. In addition, a growing number of studies have found that yawn contagion does not correlate significantly with measures of empathy20,35,36. In an attempt to delineate between the role of emotional and behavioral contagion in the contagious yawning reflex, Chan and Tseng34 compared the effects of empathy, emotional processing, and detection sensitivity to yawning in typically developing populations, finding that only the latter predicts contagious yawning. This same study found that people more likely to detect yawning, but not emotional expressions, are most likely to show contagious yawning. As it relates to group dynamics, psychopathy is thought to originate from disrupted biobehavioral synchrony61, which represents the coordination of biological and behavioral processes during social contact and is considered critical for attachment, affiliative bonds, and promoting survival activities in groups83. Thus, the reduced tendency to yawn contagiously among individuals scoring high in psychopathic traits could reflect a generalized impairment in biobehavioral synchrony. Moreover, it has been theorized that contagious yawning evolved to enhance collective vigilance48,49 and coordinate or synchronize group behavior50,51,52,53, and these functional accounts for yawn contagion can explain the negative association between contagious yawning and psychopathy in the absence of emotional contagion. For example, groups characterized by higher levels of psychopathy have previously been shown to have more dysfunctional interactions and lower levels of cohesion60.
 
An often-neglected area of study when examining variation in contagious yawning concerns underlying physiologic and circadian factors that contribute to non-social (i.e., spontaneous) yawning. Spontaneous yawns represent the primitive feature of this stereotyped action pattern, and are physiologically driven. Contagious yawning, however, represents a derived characteristic that has appeared more recently among a select group of social species14. Since the action patterns of both yawn types appear indistinguishable, the neurological mechanisms governing yawn contagion are likely mediated by the same physiological variables affecting patterns of spontaneous yawning. In support of this view, and consistent with the hypothesis that the motor action pattern of yawning evolved to increase arousal and state change1,84 via intracranial circulation and brain cooling85,86, socially-elicited forms of contagious yawning can be modulated by different methods of breathing48, time of day74, cooling/heating to the surface of forehead and neck48,78, chewing on gum76, ambient temperature variation and seasonal climactic conditions15,73,77, and acute physical stress75. Collectively these studies support the view that spontaneous and contagious forms of yawning share fundamental mechanistic pathways87. In line with this perspective, previous research has shown that both spontaneous and contagious forms of yawning are positively correlated with subjective ratings of sleepiness74,88, and the best predictor of contagious yawning here was self-reported tiredness during testing. Thus, when assessing variation in yawn contagion, we propose more attention should be given to a combination of both psychological traits as well as internal physiologic states. Franzen et al.21 provides a good example of this approach, measuring pulse rate as an indicator of sleepiness during contagious yawning trials.
 
With regards to the overall levels of psychopathy reported in this study, the mean scores and measures of variability are similar to previous community samples79,80. Previous studies have also used these instruments within incarcerated populations. In comparison to a sample of male inmates in a minimum-security prison, the current levels on the LRSPS were appreciably lower, particularly for the primary measure89. In a separate study90, which used a different Likert scale, psychopathy levels on the Dirty Dozen were also significantly higher among an incarcerated population compared to a community sample. The PPTS was designed to measure psychopathic personality regardless of respondents' criminal history, but was initially measured in two incarcerated samples81,91. In this case, the levels in these previous studies were quite similar to those reported here. Thus, future research could examine whether the negative association between psychopathy and contagious yawning would replicate in clinical or incarcerated populations.
 
While the advantages to this study include the large sample size and relatively diverse composition, there remain limitations. The reliance on self-reported contagious yawning, rather than recording physiologic- or video-confirmed instances of yawning, as was the case in Rundle et al.71 and Helt et al.19, is a notable limitation. Unfortunately, the Covid-19 pandemic dictated the online format for this study, and prevented the possibility to obtain other measures of yawn contagion. That said, there are two reasons to remain confident in the findings presented here. First, the current results largely replicate earlier studies, an effect not expected if we had obtained inaccurate measures of contagious yawning. Second, prior research has thoroughly demonstrated that self-report is a valid measure of contagious yawning based on substantial agreement between self-report and video-confirmed yawns41,69,92. That said, only a binary measure of contagious yawning was assessed, and capturing self-reported yawn frequency could have provided an important source of variability. Another limitation to this study was the lack of a non-yawning control condition. As a result, we were unable to distinguish between spontaneous yawns that could have been reported as contagious. However, we do not view this as a major concern given prior research has shown a very low rate of spontaneous yawning in response to control stimuli (3.3%)21. Overall, this study also shares limitations with most research on contagious yawning with regards to the external validity of the contagion stimuli93. In this case, participants were shown 50 consecutive yawning clips in short duration and without sound. Thus, in the future, researchers could work to develop and incorporate more ecologically valid stimuli for contagious yawning research.
 
Our measures of attention were also a limitation. We found no relationship between contagious yawning and the subjective measure of attention to the video stimulus, and an unexpected inverse association between contagious yawning and the objective measure of attention. That is, participants that correctly recalled more details from the video were less likely to report contagious yawning. These findings are difficult to reconcile with previous studies showing a significant effect of visual attention to yawning stimuli on yawn contagion19,65. It is possible that rather than providing an index of attention towards yawning, as it was intended, our measure of objective attention inadvertently captured participant attention towards other aspects of the video, such as the running tally of the total number of yawns in the upper-righthand portion of the screen. Thus, participants scoring higher on this measure may have been more attuned to outside features and actually spent less time focused on yawns, which could explain the pattern of results here. Given these limitations, and the continued debate over the roles of visual attention compared to social-connectedness in contributing to contagious yawning22,34,40,65, it is recommended that future studies use eye-tracking to assess visual attention to different features of the yawning stimulus19.
 
In summary, the current results, which to our knowledge come from the largest and most diverse sample in the study of contagious yawning to date, show a small, but significant negative relationship between psychopathic traits and the susceptibility to yawn contagiously. Limitations notwithstanding, this study provides a conceptual replication of previous research using multiple measures of psychopathy, suggesting that variability along this dimension is a true and reliable contributor to individual differences in contagious yawning in the general population. While these findings are consistent with an indirect link between contagious yawning and empathy, they also align with functional accounts of spontaneous and contagious yawning and a generalized impairment in overall patterns of behavioral contagion among people high in psychopathic traits19. Given the mixed and inconsistent psychological literature on contagious yawning, we hope this research spurs further replication efforts within this area.