-Emotional contagion -the alignment of emotions between individuals through behavioral synchronization -is proposed as a key, basic component of human social cognition and empathy. In the field of cognitive zoology, contagious behaviors have also received attention. Several such behaviors have been documented in various species. Nevertheless, emotional and behavioral contagion differ. Emotional contagion -a term predominantly used in human psychology -requires that the contagious behavior leads to converging emotional states. In non-linguistic animals, it is difficult to determine whether a behavior "caught" from someone else results in a similar affective state or remains a purely behavioral response. Some studies suggest the latter as a possibility. To disentangle the problem, we explored instances of contagious behaviors within the play domain. In several species, play involves a variety of behaviors falling into different categories: social, object and locomotor play. If a category of play in one individual induces a different category of play in another, this suggests the spread of a generally playful mood rather than a species-specific motor response. Although some studies suggest emotional contagion in mammals, it is not known whether it occurs in birds. We investigated play contagion in a group of ravens, well known for their complex social skills. The results indicate emotional contagion: the birds engaged in all categories of play on a higher level under the condition where contagion was likely to occur.

Human children show unique cognitive skills for dealing with the social world but their cognitive performance is paralleled by great apes in many tasks dealing with the physical world. Recent studies suggested that members of a songbird family—corvids—also evolved complex cognitive skills but a detailed understanding of the full scope of their cognition was, until now, not existent. Furthermore, relatively little is known about their cognitive development. Here, we conducted the first systematic, quantitative large-scale assessment of physical and social cognitive performance of common ravens with a special focus on development. To do so, we fine-tuned one of the most comprehensive experimental test-batteries, the Primate Cognition Test Battery (PCTB), to raven features enabling also a direct, quantitative comparison with the cognitive performance of two great ape species. Full-blown cognitive skills were already present at the age of four months with subadult ravens’ cognitive performance appearing very similar to that of adult apes in tasks of physical (quantities, and causality) and social cognition (social learning, communication, and theory of mind). These unprecedented findings strengthen recent assessments of ravens’ general intelligence, and aid to the growing evidence that the lack of a specific cortical architecture does not hinder advanced cognitive skills. Difficulties in certain cognitive scales further emphasize the quest to develop comparative test batteries that tap into true species rather than human specific cognitive skills, and suggest that socialization of test individuals may play a crucial role. We conclude to pay more attention to the impact of personality on cognitive output, and a currently neglected topic in Animal Cognition—the linkage between ontogeny and cognitive performance.

Conflict management strategies such as reconciliation and bystander affiliation have been described for a variety of species. A common determinant seems to be a 'complex' social life, with individuals relying on affiliate relationships or social bonds. Little is known, however, about the strategic and flexible use of conflict management skills in experimental settings in species other than primates. We here investigated conflict and post-conflict behaviour of ravens by manipulating the accessibility of food and, thus, the likelihood of aggressive interactions while foraging. Specifically, we presented birds with a certain amount of highly preferred food that varied in the number of pieces (one piece, two pieces or, as a control, small pieces matching the number of participating birds) and observed their agonistic behaviour during feeding and their affiliative behaviour afterwards. The results showed that high levels of conflicts during feeding in the 1-piece and 2-piece conditions led to high levels of affiliation after feeding. Depending on the experimental condition, this effect is best explained (a) by the affiliative behaviour of former aggressors (1-piece condition) and (b) by the affiliation directed to the receivers of aggression after feeding (2-piece condition). Those dyads that engaged in allo-preening after feeding also engaged in allo-preening outside the experimental setting, suggesting that socially bonded individuals provided third-party affiliation to victims of aggression. Moreover, socially bonded ravens fed close to each other in the experiment when food was clumped, indicating that they actively coordinated their behaviour when there was a high conflict potential. Taken together, these findings support the assumption that ravens use their social bonds to avoid conflicts by choosing with whom to feed, and to buffer effects of conflicts by engaging in third-party affiliation as post-conflict behaviour.

Conflicts are costly because they can damage social relationships. To buffer conflicts, various species use post-conflict behaviour, such as reconciliation or third-party affiliation. Both behaviours have predominantly been studied in non-human primates.However, recently, studies revealed post-conflict behaviour in other mammalian and some bird species (e.g., corvids). While third-party affiliation has been reported in several corvid species, reconciliation has only rarely been observed. The social structure of the studied groups has been postulated as a reason for the absence of reconciliation. Here, we investigated whether post-conflict behaviours in corvids indeed mirror the relationship structure. We studied the behaviour of a newly established group of juvenile carrion crows (Corvus corone corone), where pair bonds had not yet been established. We applied a combination of observations and food monopolisation experiments to quantify the use of post-conflict behaviours. Provisioning food in one or two pieces induced different patterns of aggression during feeding and differently affected the affiliation patterns after feeding. Specifically, victims of severe aggression affiliated with third parties after conflicts in the two-piece condition, while aggressors affiliated with victims of mild aggression in the one-piece condition. We thus provide the first evidence that a corvid species, crows, flexibly engage in both third-party affiliation and reconciliation. K E Y W O R D Scorvids, Corvus corone, post-conflict behaviour, reconciliation, social relationships, third-party affiliation