Attraction for familiar conspecifics in young chicks (Gallus gallus): An interbreed study.

From the beginning of life, discriminating between familiar and unfamiliar individuals and staying in contact with conspecifics are important to establish social relationships. To better understand these early social behaviours, we studied the different responses to familiar/unfamiliar individuals in 4-day-old domestic chicks (Gallus gallus) in three genetically isolated breeds: Padovana, Polverara and Robusta maculata. Chicks discriminated between familiar and unfamiliar individuals, staying closer to familiar individuals. Social reinstatement and fear responses were measured as the average distance between subjects, the latency of the first step and exploration of the arena differed between breeds. More socially motivated chicks, that stayed in closer proximity, were less afraid of starting to move and explored the environment more extensively. Interbreed differences in social reinstatement indicate that social attraction shows genetic variability from the early stages of life.

Embracing in a female-bonded monkey species (Theropithecus gelada).

[Correction Notice: An Erratum for this article was reported online in Journal of Comparative Psychology on May 9 2019 (see record 2019-25503-001). In the article "Embracing in a Female-Bonded Monkey Species (Theropithecus gelada)" by Virginia Pallante, Pier Francesco Ferrari, Marco Gamba, and Elisabetta Palagi (Journal of Comparative Psychology, Advance online publication. March 25, 2019. http://dx.doi.org/10.1037/ com0000173), the title incorrectly read "Embracing in a Female-Bonded Monkey Specie (Theropithecus gelada)" All versions of this article have been corrected.] In several primate species, including humans, embracing predicts the level of affiliation between subjects. To explore the functional meaning of embracing, we selected Theropithecus gelada as a model species. The basic level of the gelada society is the 1-male unit, and the integrity of the group is maintained by the strong bonds between females. In our study group, we observed 3 different kinds of embracing: the frontal and side embraces involving a face-to-face and chest-to-chest interaction and the posterior embrace that consists in putting the arms around conspecifics' back and posing a cheek on it. We verified that the quality of relationships between subjects predicts the type of embracing. Frontal and side embraces were more frequent between females sharing strong bonds. Posterior embracing was randomly distributed. We found a high level of female embracing among the mothers during the first months of lactation. This may improve female cohesiveness against males, thus reducing the risk of infanticide, which is particularly high in geladas. Embracing seems also to act as an ice-breaker favoring grooming. Female embracing could be an affiliative strategy that has evolved to maintain group integrity and high social cohesion among females, especially mothers. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Calming an aggressor through spontaneous post-conflict triadic contacts: Appeasement in Macaca tonkeana.

Peaceful third-party interventions usually occur after an aggressive encounter and can be directed toward the victim or the aggressor. Macaca tonkeana, a cercopithecine species characterized by high levels of tolerance, frequently engage in consolatory contacts, which both calm the victim and reduce the probability of further attacks against him/her. Other post-conflict affiliative interventions such as reconciliation and quadratic affiliation are also common in this species. However, little attention has been given to contacts directed toward the aggressor. Here, we explore the role of bystander affiliative interventions toward the aggressor in influencing the affective state of the aggressor and the consequences of triadic interventions at group level. We found that triadic post-conflict affiliation occurred independently from the intensity of the conflict and that it was more frequent in absence of the conciliatory contact between the opponents (reconciliation). Bystanders showed a higher amount of post-conflict affiliation toward low ranking aggressors. Post-conflict triadic affiliation functioned as a tension reduction mechanism by lowering the arousal of the aggressor, which less frequently engaged in renewed aggression. All these findings suggest that post-conflict triadic contacts in Tonkean macaques can be considered as a strategic mechanism to calm the aggressor and reduce the risk of retaliatory aggression.