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

Shaping behaviors through social experience and their proposed sensitivity to stress

Mammals have evolved with a range of innate drives, such as thirst and hunger, that promote motivated behaviors to ensure survival. A drive for social engagement promotes social interaction and bond formation. While a stable social environment maintains the opportunity for resource sharing and protection, an additional benefit is provided by the social transmission of information. Social experiences, and information obtained from conspecifics, can be used to learn about threats and opportunities in the environment. This review examines the primary forms of social learning and how they can shape behavior. Additionally, while there is much known about the effects of stress on learning and memory, there is much less known about its effects on social learning and memory. This review will therefore dissect the major factors that contribute to social learning and propose how stress may impact these factors. This may serve as a way to formulate new hypotheses about how stress might impact social learning and the effects of social experiences on behavior.

The relationship between psychopathy and autism: a systematic review and narrative synthesis

Background and methods

The aim of this systematic review was to synthesise research examining the relationship between autism and psychopathy to: (a) better understand the relationship between these two constructs, and (b) describe the clinical manifestation of the two when they co-occur. A systematic search of the literature returned 36 studies.

Results

Across all ages, autistic individuals and those with elevated autistic traits but no autistic diagnoses appeared to have increased callous and unemotional traits or psychopathy relative to the general population. Several studies evidenced that although both constructs are associated with empathetic dysfunction, the underlying mechanisms differ. In adults, psychopathy/psychopathic traits were associated with diminished affective empathy and intact cognitive empathy, whilst the opposite was seen autistic adults and those with elevated autistic traits. In children, those with autistic traits or a diagnosis of autism had diminished cognitive empathy, but not affective empathy, while the relationship between callous and unemotional traits/psychopathy and empathy amongst children was less clear. The co-occurrence of autism and psychopathy was seen to lead to additional empathic and cognitive impairment, but findings were mixed making it challenging to clearly describe the clinical manifestation.

Conclusion

There remains a paucity of research investigating the interaction between autism and psychopathy and included studies were characterised by multiple measurement difficulties. Attention should be directed toward developing better methods for identifying psychopathic traits in autistic individuals to advance our understanding of the relationship between autism and psychopathy to allow for the development of appropriate care pathways for this population.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=413672, identifier CRD42023413672.

Social Cognitive Correlates of Contagious Yawning and Smiling

It has been theorized that the contagion of behaviors may be related to social cognitive abilities, but empirical findings are inconsistent. We recorded young adults' behavioral expression of contagious yawning and contagious smiling to video stimuli and employed a multi-method assessment of sociocognitive abilities including self-reported internal experience of emotional contagion, self-reported trait empathy, accuracy on a theory of mind task, and observed helping behavior. Results revealed that contagious yawners reported increases in tiredness from pre- to post-video stimuli exposure, providing support for the internal experience of emotional contagion, and were more likely to provide help to the experimenter relative to non-contagious yawners. Contagious smilers showed stably high levels of self-reported happiness from pre- to post-video exposure, were more likely to provide help to the experimenter, and had increased accuracy on a theory of mind task relative to non-contagious smilers. There were no differences in self-reported trait empathy for contagious versus non-contagious yawners or smilers. Contagious yawning may be related to some basic (i.e., emotional contagion) and advanced (i.e., helping behavior) sociocognitive processes, whereas contagious smiling is related to some advanced sociocognitive processes (i.e., theory of mind and helping behavior).

The Role of Empathic Concern and Gender on Interspecific Contagious Yawning in Humans

Interspecific contagious yawning (CY), whereby yawns from one species trigger yawning in different species, has now been reported across various taxa. This response to human yawning appears common among animals in captivity and has been interpreted as an empathic response towards human handlers/caregivers. A recent study found that humans also display interspecific CY, though this response was not modulated by proxies of empathic processing (i.e., phylogenetic relatedness or social closeness to the animals). Here, we explored this relationship more explicitly by assessing how interspecific CY to yawns from common household pets relates to self-reported empathic concern. Participants (N = 103) completed a survey measuring empathic concern and then reported on their yawning behavior following exposure to a control condition or yawning images either from domesticated cats or domesticated dogs. The results provide further evidence for interspecific CY in humans, but empathic concern was negatively predictive of this response. There was also no sex difference in interspecific CY, though when comparing the sexes across CY conditions, women reported a higher frequency of yawning in response to dog yawns, and men reported a higher frequency of yawning in response to cat yawns. Overall, these findings do not support a strong connection between interspecific CY and empathy or emotional contagion.

Interspecific Contagious Yawning in Humans

Simple Summary

Contagious yawning has been observed in humans and a growing number of social vertebrates. While the majority of studies on yawn contagion have documented this phenomenon amongst conspecifics, there is also evidence for interspecific contagious yawning among non-human animals in captivity. This study was the first to formally investigate whether humans also yawn in response to yawns from different species. In particular, participants were exposed to yawning stimuli either from (1) fish, (2) amphibians, (3) reptiles, (4) birds, (5) non-primate mammals, (6) apes, or (7) domesticated cats and dogs. Overall, the results provide strong support for interspecific contagious yawning in humans, with 69% reporting yawn contagion during testing. This response was not altered by phylogenetic proximity or domestication, suggesting that the mechanisms governing yawn contagion are generalized, and can be triggered by varied representations of yawning across diverse taxa.

Abstract

Contagious yawning, or the reflexive tendency to yawn following the detection of yawning in others, is well-documented among humans and a growing number of social vertebrates. While the most common form of yawn contagion occurs between conspecifics, some non-human animals in captivity have been reported to yawn in response to yawns from human handlers/caregivers. The current research sought to provide the first formal investigation of whether people yawn contagiously in response to yawns from non-human animals. In addition, this study aimed to test whether this response was modulated by phylogenetic relatedness and domestication/social closeness. A total of 296 participants from Amazon Mechanical Turk self-reported on their yawning behavior following exposure to a (1) control (non-yawning) condition or a compilation of yawning stimuli either from (2) fish, (3) amphibians, (4) reptiles, (5) birds, (6) non-primate mammals, (7) apes, or (8) domesticated cats and dogs. The results provide strong support for interspecific yawn contagion. However, neither the propensity to yawn (binary) nor total yawn frequency varied significantly across interspecific conditions. Overall, these findings suggest that the mechanisms governing yawn contagion can be activated by varied forms of yawning stimuli, including those from distantly related and unfamiliar species.

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

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.

No Evidence for Contagious Yawning in Juvenile Ravens (Corvus corax): An Observational Study

The overt and reflexive matching of behaviors among conspecifics has been observed in a growing number of social vertebrates, including avian species. In general, behavioral contagion-such as the spread of yawning-may serve important functions in group synchronization and vigilance behavior. Here, we performed an exploratory study to investigate yawn contagion among 10 captive juvenile ravens (Corvus corax), across two groups. Using observational methods, we also examined the contagiousness of three other distinct behaviors: stretching, scratching, and shaking. A total of 44 20 min observations were made across both groups, including 28 in the morning and 16 in the afternoon. The time and occurrence of all the behaviors from each bird were coded, and the temporal pattern of each behavior across both groups was then analyzed to assess the degree of social contagion. Overall, we found no evidence for contagious yawning, stretching, scratching, or shaking. However, yawns were relatively infrequent per observation (0.052 ± 0.076 yawns/bird) and thus experimental methods should be used to support this finding.

People that score high on psychopathic traits are less likely to yawn contagiously

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, we 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.

Yawning Is More Contagious in Pregnant Than Nulliparous Women : Naturalistic and Experimental Evidence

Contrary to spontaneous yawning, which is widespread in vertebrates and probably evolutionary ancient, contagious yawning—yawning triggered by others’ yawns—is considered an evolutionarily recent phenomenon, found in species characterized by complex sociality. Whether the social asymmetry observed in the occurrence of contagious yawning is related to social and emotional attachment and may therefore reflect emotional contagion is a subject of debate. In this study we assessed whether yawn contagion was enhanced in pregnant women, a cohort of subjects who develop prenatal emotional attachment in preparation for parental care, via hormonal and neurobiological changes. We predicted that if yawn contagion underlies social and emotional attachment, pregnant women would be more likely to contagiously yawn than nonpregnant, nulliparous women of reproductive age. We gathered data in two different settings. In the experimental setting, 49 women were exposed to video stimuli of newborns either yawning or moving their mouth (control) and we video-recorded the women during repeated trials to measure their yawning response. In the naturalistic setting, 131 women were observed in a social environment and their yawning response was recorded. We tested the factors influencing the yawning response, including the reproductive status (pregnant vs. not pregnant). In both settings, yawn contagion occurred significantly more in pregnant than nonpregnant women. By showing that pregnant women were most likely to respond to others’ yawns, our results support the hypothesis that the social variation observed in yawn contagion may be influenced by emotional attachment and that yawning in highly social species might have been coopted for emotional contagion during evolution.