When is emotional contagion adaptive?

Emotions spread like contagious diseases

Emotional contagion, that is, the spontaneous synchronization of emotions among individuals, is the basic mechanism of social cohesion and survival of different species. Emotional contagion can be observed in humans and many animals, and it has become an effective means to protect individuals from danger. The study of emotional contagion in different animals is of evolutionary significance, and in human society, emotional contagion has an important impact on mental health and group behavior. However, the existing research still has obvious shortcomings in the similarities and differences of cross-species emotional contagion, the communication dynamics in virtual space and the infectious effect of positive emotions. This paper reviews the mechanisms of emotional contagion in different species, such as rodents, nonhuman primates, dogs, crows and zebrafish, highlighting evolutionary conservatism and species-specific adaptation, and analyzes the role of human children's behavioral mimicry in its early development. Furthermore, we extend the discussion of emotional contagion to virtual social networks, revealing the unique communication mechanism in online environment. In addition, by combing the sociological model and the emerging neurocognitive model, the complex process of emotional contagion can be explained more comprehensively. Through multidisciplinary perspective, it provides systematic theoretical and empirical support for us to understand emotional contagion.

A dyadic investigation of shy children's behavioral and affective responses to delivering a speech

Shyness is typically associated with avoidant social behavior and restricted affect in new social situations. However, we know considerably less about how one child's shyness influences another child's behavior and affect in new social situations. Children's shyness was parent-reported when children were age 3 (N = 105, 52 girls, Mage = 3.50 years), and children were tested approximately 1 year later (Mage = 4.76 years) in same-gender dyads where they were asked to give an impromptu speech about their most recent birthday in front of an experimenter and the other member of the dyad. We examined whether children's shyness and speech order influenced their own and their social partner's observed behavior and affect during the speech. Regardless of speech order, children's own shyness was positively associated with their own avoidant social behavior and gaze aversion. Regardless of shyness, children who gave their speech second averted their gaze more than children who gave their speech first. We also found that children who gave their speech second displayed less positive affect if their social partner who they watched give the speech first was shyer. We speculate that some 4-year-old children may be sensitive to the avoidant behaviors of their shy peers and, in turn, respond with less animation when it is their turn to participate in the same activity. RESEARCH HIGHLIGHTS: We examined whether preschool children's shyness and speech order influenced their own and their social partner's observed behavior and affect during a dyadic speech task Children's own shyness was positively associated with their own avoidant social behavior and gaze aversion Children who gave their speech second averted their gaze more than children who gave their speech first. Children who gave their speech second displayed less positive affect if their social partner who they watched give a speech first was shyer These findings suggest that preschool-aged children are sensitive to learning about their environment indirectly through social observation.

Cheerful tails: Delving into positive emotional contagion

This review delves into the phenomenon of positive emotional contagion (PEC) in rodents, an area that remains relatively understudied compared to the well-explored realm of negative emotions such as fear or pain. Rodents exhibit clear preferences for individuals expressing positive emotions over neutral counterparts, underscoring the importance of detecting and responding to positive emotional signals from others. We thoroughly examine the adaptive function of PEC, highlighting its pivotal role in social learning and environmental adaptation. The developmental aspect of the ability to interpret positive emotions is explored, intricately linked to maternal care and social interactions, with oxytocin playing a central role in these processes. We discuss the potential involvement of the reward system and draw attention to persisting gaps in our understanding of the neural mechanisms governing PEC. Presenting a comprehensive overview of the existing literature, we focus on food-related protocols such as the Social Transmission of Food Preferences paradigm and tickling behaviour. Our review emphasizes the pressing need for further research to address lingering questions and advance our comprehension of positive emotional contagion.

Emotional contagion in rodents: A comprehensive exploration of mechanisms and multimodal perspectives

Emotional contagion, a fundamental aspect of empathy, is an automatic and unconscious process in which individuals mimic and synchronize with the emotions of others. Extensively studied in rodents, this phenomenon is mediated through a range of sensory pathways, each contributing distinct insights. The olfactory pathway, marked by two types of pheromones modulated by oxytocin, plays a crucial role in transmitting emotional states. The auditory pathway, involving both squeaks and specific ultrasonic vocalizations, correlates with various emotional states and is essential for expression and communication in rodents. The visual pathway, though less relied upon, encompasses observational motions and facial expressions. The tactile pathway, a more recent focus, underscores the significance of physical interactions such as allogrooming and socio-affective touch in modulating emotional states. This comprehensive review not only highlights plausible neural mechanisms but also poses key questions for future research. It underscores the complexity of multimodal integration in emotional contagion, offering valuable insights for human psychology, neuroscience, animal welfare, and the burgeoning field of animal-human-AI interactions, thereby contributing to the development of a more empathetic intelligent future.

The effects of adapted physical education sessions on the empathy of female students with overweight

The global prevalence of childhood and adolescent overweight and obesity increases rapidly. Physical activity plays a major role in the prevention of obesity. The present study aimed to analyze the effect of adapted basketball sessions according to the empathic capacity of adolescent girls with overweight. Forty-two girls with overweight (age: 16.09 ± 0.85; years; height: 1.64 ± 0.67 m: weight: 73.02 ± 0.61 kg; BMI: 27.15 ± 1.37) volunteered to participate in the study and were randomly assigned to the experimental group (EG, n = 21) and control group (CG, n = 21). EG was submitted to a basketball intervention adapted to students with obesity while the CG performed classic basketball exercises for 7 weeks. Each week girls had 2 basketball teaching-learning sessions, lasting 50 min. The participants' empathy was assessed before and after the intervention using the Favre CEC. The results showed that adaptation intervention was associated with a significant emotional contagion decrease (Δ% = 0.466) and splitting with emotions (Δ% = 0.375), and with an empathy increase (Δ% = 1.387), in EG compared to CG. No significant difference was assessed in the empathy CG, before and after the intervention. This study demonstrated that adapted physical education classes could be an effective strategy to improve empathetic skills and inclusion of overweight girls as well as a means to prevent obesity.

Entropy and Fractal Techniques for Monitoring Fish Behaviour and Welfare in Aquacultural Precision Fish Farming-A Review

In a non-linear system, such as a biological system, the change of the output (e.g., behaviour) is not proportional to the change of the input (e.g., exposure to stressors). In addition, biological systems also change over time, i.e., they are dynamic. Non-linear dynamical analyses of biological systems have revealed hidden structures and patterns of behaviour that are not discernible by classical methods. Entropy analyses can quantify their degree of predictability and the directionality of individual interactions, while fractal dimension (FD) analyses can expose patterns of behaviour within apparently random ones. The incorporation of these techniques into the architecture of precision fish farming (PFF) and intelligent aquaculture (IA) is becoming increasingly necessary to understand and predict the evolution of the status of farmed fish. This review summarizes recent works on the application of entropy and FD techniques to selected individual and collective fish behaviours influenced by the number of fish, tagging, pain, preying/feed search, fear/anxiety (and its modulation) and positive emotional contagion (the social contagion of positive emotions). Furthermore, it presents an investigation of collective and individual interactions in shoals, an exposure of the dynamics of inter-individual relationships and hierarchies, and the identification of individuals in groups. While most of the works have been carried out using model species, we believe that they have clear applications in PFF. The review ends by describing some of the major challenges in the field, two of which are, unsurprisingly, the acquisition of high-quality, reliable raw data and the construction of large, reliable databases of non-linear behavioural data for different species and farming conditions.

Tickle contagion in the rat somatosensory cortex

The cellular mechanisms of emotional contagion are unknown. We investigated tickle contagion and the underlying neuronal representations in playful rats. We recorded trunk somatosensory cortex activity of observer rats while they received tickling and audiovisual playback of tickling footage and while they witnessed tickling of demonstrator rats. Observers vocalized and showed "Freudensprünge" ("joy jumps") during witnessing live tickling, while they showed little behavioral responses to playbacks. Deep layers in the trunk somatosensory neurons showed a larger correlation between direct and witnessed tickling responses compared to superficial layers. Trunk somatosensory neurons discharged upon emission of own and demonstrator's vocalizations and might drive contagious "laughter". We conclude that trunk somatosensory cortex might represent ticklishness contagion.

Reading emotions in Dogs' eyes and Dogs' faces

Our primary goal was to investigate human ability to recognize basic emotions from only the eyes of dogs in comparison to the whole face. Simultaneously, we replicated and extended previous research (Bloom et al., 2021), while validating American canine emotional facial expression photographs cross-culturally to Brazil. Participants (N = 120) viewed behaviorally-anchored photographs of three breeds. Half the participants in each condition (faces or eyes-only) viewed two-word forced choice items while the other half viewed four-word forced choice items. Participants identified target emotions from images of both dogs' faces and eyes-only at a higher rate than chance. Fear was accurately recognized more than the other emotions. When dogs are afraid, they open their eyes and expose the sclera, a conspicuous signal. Emotion identification accuracy was highest for the Rhodesian Ridgeback, who is similar in morphology to common Brazilian stray dogs (Vira-Latas Carmelo). We conjectured that Brazilians were more accustomed to seeing dogs with the Rhodesian Ridgeback morphology than the erect-eared breeds, thus increasing accuracy for this breed. Further studies with additional dog morphologies are desirable. In addition to research interest, our Canine Eyes task has the potential to become a test of individual differences in Theory of Mind with clinical applications.

The social transmission of stress in animal collectives

The stress systems are powerful mediators between the organism's systemic dynamic equilibrium and changes in its environment beyond the level of anticipated fluctuations. Over- or under-activation of the stress systems' responses can impact an animal's health, survival and reproductive success. While physiological stress responses and their influence on behaviour and performance are well understood at the individual level, it remains largely unknown whether-and how-stressed individuals can affect the stress systems of other group members, and consequently their collective behaviour. Stressed individuals could directly signal the presence of a stressor (e.g. via an alarm call or pheromones), or an acute or chronic activation of the stress systems could be perceived by others (as an indirect cue) and spread via social contagion. Such social transmission of stress responses could then amplify the effects of stressors by impacting social interactions, social dynamics and the collective performance of groups. As the neuroendocrine pathways of the stress response are highly conserved among vertebrates, transmission of physiological stress states could be more widespread among non-human animals than previously thought. We therefore suggest that identifying the extent to which stress transmission modulates animal collectives represents an important research avenue.

Contagious Depression: Automatic Mimicry and the Mirror Neuron System - A Review

Contagious depression is a theory proposing that depression can be induced or triggered by our social environment. This theory is based on emotional contagion, the idea that affective states can be transferred during social interaction, since humans can use emotional contagion to communicate feelings and emotions in conscious and unconscious ways. This review presents behavioral, physiological, and neuroanatomical aspects of two essential contagious depression mechanisms, automatic mimicry and the mirror neuron system.

Collective Emotional Contagion in Zebrafish

Seeking to match our emotional state with one of those around us is known as emotional contagion-a fundamental biological process that underlies social behavior across several species and taxa. While emotional contagion has been traditionally considered to be a prerogative of mammals and birds, recent findings are demonstrating otherwise. Here, we investigate emotional contagion in groups of zebrafish, a freshwater model species which is gaining momentum in preclinical studies. Zebrafish have high genetic homology to humans, and they exhibit a complex behavioral repertoire amenable to study social behavior. To investigate whether individual emotional states can be transmitted to group members, we pharmacologically modulated anxiety-related behaviors of a single fish through Citalopram administration and we assessed whether the altered emotional state spread to a group of four untreated conspecifics. By capitalizing upon our in-house developed tracking algorithm, we successfully preserved the identity of all the subjects and thoroughly described their individual and social behavioral phenotypes. In accordance with our predictions, we observed that Citalopram administration consistently reduced behavioral anxiety of the treated individual, in the form of reduced geotaxis, and that such a behavioral pattern readily generalized to the untreated subjects. A transfer entropy analysis of causal interactions within the group revealed that emotional contagion was directional, whereby the treated individual influenced untreated subjects, but not vice-versa. This study offers additional evidence that emotional contagion is biologically preserved in simpler living organisms amenable to preclinical investigations.

A Social Learning Perspective on the Trickle-Down of Psychological Empowerment from Supervisor to Subordinate

Abstract. Because of its relevance for organizations and their employees, psychological empowerment (PE) has received a great deal of attention in research and practice. Supervisors play an important role in the promotion of subordinates’ PE. In the present article, and on the basis of social learning theory, we examine how the supervisor’s perceived and self-reported PE influence the subordinate’s PE. The results of two multi-wave studies involving more than 1,000 participants suggest that the supervisor’s perceived PE can predict the subordinate’s PE. The supervisor’s self-reported PE did not affect the subordinate’s PE: PE does not seem to trickle down from supervisor to subordinate. The relationship between the supervisor’s perceived PE and the subordinate’s PE was stronger when trust in the supervisor was higher. Supervisors who want to promote subordinates’ PE through modeling should therefore ensure that they are perceived as psychologically empowered and invest in relationships of trust with their subordinates.

Earlier than previously thought: Yawn contagion in preschool children

Yawning is a primitive and stereotyped motor action involving orofacial, laryngeal, pharyngeal, thoracic and abdominal muscles. Contagious yawning, an involuntarily action induced by viewing or listening to others' yawns, has been demonstrated in human and several non-human species. Previous studies with humans showed that infants and preschool children, socially separated during video experiments, were not infected by others' yawns. Here, we tested the occurrence of yawn contagion in 129 preschool children (ranging from 2.5 to 5.5 years) belonging to five different classes by video recording them in their classrooms during the ordinary school activities. As it occurs in adult humans, children of all ages were infected by others' yawns within the 2 min after the perception of the stimulus. The yawn contagion occurred earlier than previously thought. For children, it appears that the natural social setting is more conducive to yawn contagion than the inherently artificial experimental approach. Moreover, children's gender did not affect the level of contagious yawning. The neural, emotional and behavioural traits of preschool children are probably not sufficiently mature to express variability between boys and girls; nevertheless, children appeared to be already well equipped with the 'neural toolkit' necessary for expressing yawn contagion.

Challenges in the comparative study of empathy and related phenomena in animals

The aim of this review is to discuss recent arguments and findings in the comparative study of empathy. Based on a multidisciplinary approach including psychology and ethology, we review the non-human animal literature concerning theoretical frameworks, methodology, and research outcomes. One specific objective is to highlight discrepancies between theory and empirical findings, and to discuss ambiguities present in current data and their interpretation. In particular, we focus on emotional contagion and its experimental investigation, and on consolation and targeted helping as measures for sympathy. Additionally, we address the feasibility of comparing across species with behavioural data alone. One main conclusion of our review is that animal research on empathy still faces the challenge of closing the gap between theoretical concepts and empirical evidence. To advance our knowledge, we propose to focus more on the emotional basis of empathy, rather than on possibly ambiguous behavioural indicators, and we provide suggestions to overcome the limitations of previous research .

Conformity-like behaviour in mice observing the freezing of other mice: a model of empathy

Background

Empathy refers to the ability to recognise and share emotions with others. Several research groups have recognised observational fear in mice as a useful behavioural model for assessing their ability to empathise. However, in these observation systems, it remains unclear whether the observer mouse truly recognises the movements of, and empathises with, the demonstrator mouse. We examined changes in the behaviour of an observer mouse when a demonstrator mouse was anaesthetised, when the demonstrator’s activity was increased, and when the interval of electrical stimulation was altered. If mice exhibit an ability to empathise, then the observer should display empathic behaviour when the demonstrator experiences pain or discomfort under any circumstances.

Results

Relative to low-frequency stimulation, frequent electrical stimulation reduced immobility time among observer mice. Moreover, when demonstrators exhibited excessive activity, the activity of the observers significantly increased. In addition, the proportion of immobility time among observer mice significantly increased when demonstrator mice exhibited fear learning and excessive immobility.

Conclusion

Although our results indicate that observer mice change their behaviour based on the movements of demonstrator mice, increases in immobility time may reflect conformity-like behaviour rather than emotional empathy. Thus, not only visual but also auditory and odour information additionally influenced the conformity-like behaviour shown by observer mice. Thus, our findings suggest that methods other than the fear observation system should be used to investigate rodent empathy-like behaviour.

The social life of Norway rats (Rattus norvegicus)

The Norway rat has important impacts on our life. They are amongst the most used research subjects, resulting in ground-breaking advances. At the same time, wild rats live in close association with us, leading to various adverse interactions. In face of this relevance, it is surprising how little is known about their natural behaviour. While recent laboratory studies revealed their complex social skills, little is known about their social behaviour in the wild. An integration of these different scientific approaches is crucial to understand their social life, which will enable us to design more valid research paradigms, develop more effective management strategies, and to provide better welfare standards. Hence, I first summarise the literature on their natural social behaviour. Second, I provide an overview of recent developments concerning their social cognition. Third, I illustrate why an integration of these areas would be beneficial to optimise our interactions with them.

Intraspecific Motor and Emotional Alignment in Dogs and Wolves: The Basic Building Blocks of Dog-Human Affective Connectedness

Involuntary synchronization occurs when individuals perform the same motor action patterns during a very short time lapse. This phenomenon serves an important adaptive value for animals permitting them to socially align with group fellows thus increasing integration and fitness benefits. Rapid mimicry (RM) and yawn contagion (YC) are two behavioral processes intermingled in the animal synchronization domain. Several studies demonstrated that RM and YC are socially modulated being more frequently performed by individuals sharing close relationships. This evidence highlights the relation between RM/YC and emotional contagion that is the capacity of two or more individuals to share the same affective state. In this review, we try to delineate a possible developmental trajectory of emotional sharing phenomena by using, as a model species, the domestic dog (Canis lupus familiaris), a valid example of empathic predisposition towards individuals belonging both to the same and the different species. We contrast available findings on RM and YC in dog-dog and dog-human dyads with those in wolf-wolf dyads, in order to investigate if the ability to emotionally engage with conspecifics (wolf-wolf and dog-dog) is evolutionary rooted in canids and if provides the basis for the development of inter-specific emotional sharing (dog-human).

Sharing playful mood: rapid facial mimicry in Suricata suricatta

One of the most productive behavioural domains to study visual communication in mammals is social play. The ability to manage play-fighting interactions can favour the development of communicative modules and their correct decoding. Due to their high levels of social cohesion and cooperation, slender-tailed meerkats (Suricata suricatta) are a very good model to test some hypotheses on the role of facial communication in synchronizing playful motor actions. We found that the relaxed open mouth (ROM), a playful facial expression conveying a positive mood in several social mammals, is also present in meerkats. ROM was mainly perceived during dyadic playful sessions compared to polyadic ones. We also found that meerkats mimic in a very rapid and automatic way the ROM emitted by playmates (Rapid Facial Mimicry, RFM). RFM was positively correlated with the relationship quality shared by subjects, thus suggesting that the mimicry phenomenon is socially modulated. Moreover, more than the mere presence of isolated ROMs, the presence of at RFM prolonged the duration of the play session. Through RFM animals can share the emotional mood, they are experiencing and this appears to be particularly adaptive in those species, whose relationships are not inhibited by rank rules and when animals build and maintain their bonds through social affiliation. The meerkat society is cohesive and cooperative. Such features could have, therefore, favoured the evolution of facial mimicry, a phenomenon linked to emotional contagion, one of the most basic forms of empathy.

The complexity of understanding others as the evolutionary origin of empathy and emotional contagion

Contagious yawning, emotional contagion and empathy are characterized by the activation of similar neurophysiological states or responses in an observed individual and an observer. For example, it is hard to keep one’s mouth closed when imagining someone yawning, or not feeling distressed while observing other individuals perceiving pain. The evolutionary origin of these widespread phenomena is unclear, since a direct benefit is not always apparent. We explore a game theoretical model for the evolution of mind-reading strategies, used to predict and respond to others’ behavior. In particular we explore the evolutionary scenarios favoring simulative strategies, which recruit overlapping neural circuits when performing as well as when observing a specific behavior. We show that these mechanisms are advantageous in complex environments, by allowing an observer to use information about its own behavior to interpret that of others. However, without inhibition of the recruited neural circuits, the observer would perform the corresponding downstream action, rather than produce the appropriate social response. We identify evolutionary trade-offs that could hinder this inhibition, leading to emotional contagion as a by-product of mind-reading. The interaction of this model with kinship is complex. We show that empathy likely evolved in a scenario where kin- and other indirect benefits co-opt strategies originally evolved for mind-reading, and that this model explains observed patterns of emotional contagion with kin or group members.

Looking on the Bright Side of Livestock Emotions-the Potential of Their Transmission to Promote Positive Welfare

Emotions can be defined as an individual's affective reaction to an external and/or internal event that, in turn, generates a simultaneous cascade of behavioral, physiological, and cognitive changes. Those changes that can be perceived by conspecifics have the potential to also affect other's emotional states, a process labeled as "emotional contagion." Especially in the case of gregarious species, such as livestock, emotional contagion can have an impact on the whole group by, for instance, improving group coordination and strengthening social bonds. We noticed that the current trend of research on emotions in livestock, i.e., investigating affective states as a tool to assess and improve animal welfare, appears to be unbalanced. A majority of studies focuses on the individual rather than the social component of emotions. In this paper, we highlight current limitations in the latter line of research and suggest a stronger emphasis on the mechanisms of how emotions in livestock are transmitted and shared, which could serve as a promising tool to synergistically enhance the welfare of all individuals within a group.

Evolution of emotional contagion in group-living animals

Emotional contagion refers to an instantaneous matching of an emotional state between a subject and an object. It is believed to form one of the bases of empathy and it causes consistent group behavior in many animals. However, how this emotional process relates to group size remains unclear. Individuals with the ability of emotional contagion can instantaneously copy the emotion of another group member and can take relevant behavior driven by this emotion, but this would entail both cost and benefit to them because the behavior can be either appropriate or inappropriate depending on the situation. For example, emotional contagion may help them escape from a predator but sometimes induce mass panic. We theoretically study how these two aspects of emotional contagion affect its evolution in group-living animals. We consider a situation where an environmental cue sometimes indicates a serious event and individuals have to make a decision whether to react to them. We show that, as the group size increases, individuals with the ability of emotional contagion would evolutionarily weaken their sensitivity to environmental cues. We also show that a larger group yields a larger benefit to them through such evolutionary change. However, larger group size prevents the invasion of mutants with the ability of emotional contagion into the population of residents who react to environmental cues independently of other group members. These results provide important suggestions on the evolutionary relationship between emotional contagion and group living.

Effects of 25 mg oxazepam on emotional mimicry and empathy for pain: a randomized controlled experiment

Emotional mimicry and empathy are mechanisms underlying social interaction. Benzodiazepines have been proposed to inhibit empathy and promote antisocial behaviour. First, we aimed to investigate the effects of oxazepam on emotional mimicry and empathy for pain, and second, we aimed to investigate the association of personality traits to emotional mimicry and empathy. Participants (n=76) were randomized to 25 mg oxazepam or placebo. Emotional mimicry was examined using video clips with emotional expressions. Empathy was investigated by pain stimulating the participant and a confederate. We recorded self-rated experience, activity in major zygomatic and superciliary corrugator muscles, skin conductance, and heart rate. In the mimicry experiment, oxazepam inhibited corrugator activity. In the empathy experiment, oxazepam caused increased self-rated unpleasantness and skin conductance. However, oxazepam specifically inhibited neither emotional mimicry nor empathy for pain. Responses in both experiments were associated with self-rated empathic, psychopathic and alexithymic traits. The present results do not support a specific effect of 25 mg oxazepam on emotional mimicry or empathy.

Effects of 25 mg oxazepam on emotional mimicry and empathy for pain: a randomized controlled experiment

Emotional mimicry and empathy are mechanisms underlying social interaction. Benzodiazepines have been proposed to inhibit empathy and promote antisocial behaviour. First, we aimed to investigate the effects of oxazepam on emotional mimicry and empathy for pain, and second, we aimed to investigate the association of personality traits to emotional mimicry and empathy. Participants (n=76) were randomized to 25 mg oxazepam or placebo. Emotional mimicry was examined using video clips with emotional expressions. Empathy was investigated by pain stimulating the participant and a confederate. We recorded self-rated experience, activity in major zygomatic and superciliary corrugator muscles, skin conductance, and heart rate. In the mimicry experiment, oxazepam inhibited corrugator activity. In the empathy experiment, oxazepam caused increased self-rated unpleasantness and skin conductance. However, oxazepam specifically inhibited neither emotional mimicry nor empathy for pain. Responses in both experiments were associated with self-rated empathic, psychopathic and alexithymic traits. The present results do not support a specific effect of 25 mg oxazepam on emotional mimicry or empathy.

Differential influence of social versus isolate housing on vicarious fear learning in adolescent mice

Laboratory rodents can adopt the pain or fear of nearby conspecifics. This phenotype conceptually lies within the domain of empathy, a bio-psycho-social process through which individuals come to share each other's emotion. Using a model of cue-conditioned fear, we show here that the expression of vicarious fear varies with respect to whether mice are raised socially or in solitude during adolescence. The impact of the adolescent housing environment was selective: (a) vicarious fear was more influenced than directly acquired fear, (b) "long-term" (24-h postconditioning) vicarious fear memories were stronger than "short-term" (15-min postconditioning) memories in socially reared mice whereas the opposite was true for isolate mice, and (c) females were more fearful than males. Housing differences during adolescence did not alter the general mobility of mice or their vocal response to receiving the unconditioned stimulus. Previous work with this mouse model underscored a genetic influence on vicarious fear learning, and the present study complements these findings by elucidating an interaction between the adolescent social environment and vicarious experience. Collectively, these findings are relevant to developing models of empathy amenable to mechanistic exploitation in the laboratory. (PsycINFO Database Record

Rapid mimicry and emotional contagion in domestic dogs

Emotional contagion is a basic form of empathy that makes individuals able to experience others' emotions. In human and non-human primates, emotional contagion can be linked to facial mimicry, an automatic and fast response (less than 1 s) in which individuals involuntary mimic others' expressions. Here, we tested whether body (play bow, PBOW) and facial (relaxed open-mouth, ROM) rapid mimicry is present in domestic dogs (Canis lupus familiaris) during dyadic intraspecific play. During their free playful interactions, dogs showed a stronger and rapid mimicry response (less than 1 s) after perceiving PBOW and ROM (two signals typical of play in dogs) than after perceiving JUMP and BITE (two play patterns resembling PBOW and ROM in motor performance). Playful sessions punctuated by rapid mimicry lasted longer that those sessions punctuated only by signals. Moreover, the distribution of rapid mimicry was strongly affected by the familiarity linking the subjects involved: the stronger the social bonding, the higher the level of rapid mimicry. In conclusion, our results demonstrate the presence of rapid mimicry in dogs, the involvement of mimicry in sharing playful motivation and the social modulation of the phenomenon. All these findings concur in supporting the idea that a possible linkage between rapid mimicry and emotional contagion (a building-block of empathy) exists in dogs.