Sharing emotions builds bridges between individuals and between species

Many animal species express, perceive and share emotions. These abilities have been favoured by natural selection because they allow subjects to respond to various situations in an appropriate way, thus facilitating survival and increasing fitness. The same-face/same-emotion phenomenon is at the basis of sharing feelings and emotions. Recent studies show that this capacity is not unique to humans and that it plays an important role in creating cohesive societies in many different species

Not just for fun! social play as a springboard for adult social competence in human and non-human primates

Play is one of the most difficult behaviors to quantify and for this reason, its study has had a very rocky history. Social play is ephemeral, difficult to distinguish from the other so-called serious behaviors, not so frequent (especially in sexually mature subjects), fast, and complex to describe. Due to its multifaceted nature, it has often been considered as a wastebasket category that has included all kinds of the behaviors not showing any immediate, obvious goal. Yet, play is widespread across the whole primate order and can have a strong impact on the development of cognitive, psychological, and social skills of many species, including humans. Unlike functional behaviors that are specifically and economically performed to reduce uncertainty and to increase the opportunity to gain resources, play seems to introduce and increase uncertainty, creating new challenges for the animals. For this reason, social play has been hypothesized to be the engine of behavioral innovation in ontogeny. From the first mild and gentle interactions with the mother to the most sophisticated play fighting sessions and acrobatic action sequences with peers, play represents for juveniles (and not only for them!) a window onto the social and physical environment. In this review, I focus on social play and its relation to adult social competence. By playing, juveniles acquire competence to manage interactions with conspecifics, enlarge their social networks, and test their physical power and motor skills (i.e., long-term benefits). At the same time, I propose the view that play—due to its plastic and versatile nature—can be used in an opportunistic way, as a joker behavior, throughout life to strategically obtain short-term or immediate benefits. I put forward the hypothesis that, during ontogeny, the joker function of play can be modulated according to the differing inter-individual relationships present in the diverse societies, characterizing the primate order

Ontogenetic Trajectories of Chimpanzee Social Play: Similarities with Humans

Social play, a widespread phenomenon in mammals, is a multifunctional behavior, which can have many different roles according to species, sex, age, relationship quality between playmates, group membership, context, and habitat. Play joins and cuts across a variety of disciplines leading directly to inquiries relating to individual developmental changes and species adaptation, thus the importance of comparative studies appears evident. Here, we aim at proposing a possible ontogenetic pathway of chimpanzee play (Pan troglodytes) and contrast our data with those of human play. Chimpanzee play shows a number of changes from infancy to juvenility. Particularly, solitary and social play follows different developmental trajectories. While solitary play peaks in infancy, social play does not show any quantitative variation between infancy and juvenility but shows a strong qualitative variation in complexity, asymmetry, and playmate choice. Like laughter in humans, the playful expressions in chimpanzees (at the different age phases) seem to have a role in advertising cooperative dispositions and intentions thus increasing the likelihood of engaging in solid social relationships. In conclusion, in chimpanzees, as in humans, both play behavior and the signals that accompany play serve multiple functions according to the different age phases

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

The right time to happen: play developmental divergence in the two Pan species

Bonobos, compared to chimpanzees, are highly motivated to play as adults. Therefore, it is interesting to compare the two species at earlier developmental stages to determine how and when these differences arise. We measured and compared some play parameters between the two species including frequency, number of partners (solitary, dyadic, and polyadic play), session length, and escalation into overt aggression. Since solitary play has a role in developing cognitive and physical skills, it is not surprising that chimpanzees and bonobos share similar developmental trajectories in the motivation to engage in this activity. The striking divergence in play developmental pathways emerged for social play. Infants of the two species showed comparable social play levels, which began to diverge during the juvenile period, a ‘timing hotspot’ for play development. Compared to chimpanzees, social play sessions in juvenile bonobos escalated less frequently into overt aggression, lasted longer, and frequently involved more than two partners concurrently (polyadic play). In this view, play fighting in juvenile bonobos seems to maintain a cooperative mood, whereas in juvenile chimpanzees it acquires more competitive elements. The retention of juvenile traits into adulthood typical of bonobos can be due to a developmental delay in social inhibition. Our findings show that the divergence of play ontogenetic pathways between the two Pan species and the relative emergence of play neotenic traits in bonobos can be detected before individuals reach sexual maturity. The high play motivation showed by adult bonobos compared to chimpanzees is probably the result of a long developmental process, rooted in the delicate transitional phase, which leads subjects from infancy to juvenilit

The Season for Peace: Reconciliation in a Despotic Species (Lemur catta)

However despotic a social group may be, managing conflicts of interest is crucial to preserve group living benefits, mainly based on cooperation. In despotic groups, post-conflict management via reconciliation (the first post-conflict reunion between former opponents) can occur, even if conciliatory rates are considerably different. Lemur catta is defined as a despotic species because groups are characterized by a strict linear hierarchy maintained by the adult females (the dominant sex) mainly via aggression. Reconciliation was reported in one out of four captive groups of L. catta. Here we investigate which variables influence the occurrence of reconciliation in these despotic groups. We analyzed 2339 Post Conflict (PC)-Matched Control (MC) observation pairs, collected on eight groups (five in the Berenty forest, Madagascar; three hosted at the Pistoia Zoo, Italy). Since L. catta is characterized by steep female dominance but shows female-female coalitionary support, we expected to confirm the presence of reconciliation in the study species. Consistently, we found reconciliation in one captive group and two wild groups, thus providing the first evidence of the presence of this phenomenon in wild L. catta. Moreover, because this species is a seasonal breeder (with mating occurring once a year), we expected seasonal fluctuations in reconciliation levels. Via a GLMM analysis using data from all wild groups and on a captive group followed for more than one year, we found that season (but not rank; individuals’ identity, sex, and age; or group identity) significantly affected individual reconciliation rates, and such rates were lowest during the mating period. Thus, reconciliation can be present in groups in which dominants strongly influence and limit social relationships (steep dominance hierarchy) except when the advantages of intra-group cooperation are overcome by competition, as occurs in seasonal breeders when reproduction is at stake. We conclude that in despotic social groups in which coalitions are observed, the right question is not if but when reconciliation can be present. Introductio

Laughter, play faces and mimicry in animals: evolution and social functions

Human laughter and laugh faces show similarities in morphology and function with animal playful expressions. To better understand primordial uses and effects of human laughter and laugh faces, it is important to examine these posi tive expressions in animals from both homologous and analogous systems. Phylogenetic research on hominids provided empirical evidence on shared ancestry across these emotional expressions, including human laughter and laugh faces. In addition, playful expressions of animals, in general, arguably have a key role in the development of social cognitive skills, a role that may help explain their polyphyletic history. The present work examines the evol ution and function of playful expressions in primates and other animals. As part of this effort, we also coded for muscle activations of six carnivore taxa with regard to their open-mouth faces of play; our findings provide evidence that these carnivore expressions are homologues of primate open-mouth faces of play. Furthermore, our work discusses how the expressions of animal play may communicate positive emotions to conspecifics and how the motor reson ance of these expressions increases affiliation and bonding between the subjects, resembling in a number of ways the important social–emotional effects that laughter and laugh faces have in humans

Yawn contagion in humans and bonobos: emotional affinity matters more than species.

In humans and apes, yawn contagion echoes emotional contagion, the basal layer of empathy. Hence, yawn contagion is a unique tool to compare empathy across species. If humans are the most empathic animal species, they should show the highest empathic response also at the level of emotional contagion. We gathered data on yawn contagion in humans (Homo sapiens) and bonobos (Pan paniscus) by applying the same observational paradigm and identical operational definitions .W eselected a naturalistic approach because experimental management practices can produce different psychological and behavioural biases in the two species, and differential attention to artificia lstimuli .Withi nspecies ,yaw ncontagio nwa shighes tbetween strongly bonded subjects. Between species, sensitivity to others\u27 yawns was higher in humans than in bonobos when involving kin and friends but was similar when considering weakly-bonded subjects. Thus, emotional contagion is not always high- est in humans. The cognitive components concur in empowering emotional affinity between individuals. Yet, when they are not in play, humans climb down from the empathic podium to return to the "understory", which our species shares with apes