Biology subjects

Hirel, M.

Publications and source records attributed to Hirel, M..

4 recordsLinked to original sources

bioRxiv2025

Social evaluation of skilfulness in Tonkean macaques (Macaca tonkeana) and brown capuchins (Sapajus apella)

For optimal decision-making, social animals can benefit from evaluating others behaviours. Some species seemingly consider the skills of others when deciding who to interact with in different contexts. Yet, whether and how nonhuman animals form impressions about others competence is still unclear. In this study, we investigated whether Tonkean macaques (Macaca tonkeana) and brown capuchins (Sapajus apella) can evaluate the skilfulness of others. Subjects observed two human actors (one skilful, one unskilled) trying to open several food containers. Only the skilful actor successfully opened the containers and released food so the experimenter could give it to the subjects. Afterwards, subjects did not choose the skilful actor significantly more frequently than the unskilled one. Their choices for the skilful actor did not increase through trials, nor were they based on the outcomes experienced in previous trials. However, when we considered their initial preferences for the human actors, we observed a significant shift in preference for the skilful actor. Our subjects also looked preferentially at the skilful over the unskilled actor when both simultaneously manipulated a container. We observed substantial individual variation and species differences in choice and looking behaviours. While the cognitive mechanisms (impression formation vs outcome-based process) underlying these social decisions are still unclear, our findings indicate that Tonkean macaques and brown capuchins used social information about the actors skills to inform their decisions.

animal behavior and cognition↗

bioRxiv2025

Tonkean macaques do not prefer the helper or the hinderer in the hill paradigm

Evaluating others prosocial tendencies can benefit individuals by allowing them to interact with prosocial individuals and avoid antisocial ones. The ontogeny of humans strong prosocial preference has been widely investigated using the hill paradigm. Childrens preference for helper over hinderer agents was measured after they watched a scene in which the helper agent pushed a climber up a hill while the hinderer agent pushed the climber down the hill. Bonobos tested with the hill paradigm preferred the hinderer over the helper, contrasting previous findings for other nonhuman primates. We tested Tonkean macaques (Macaca tonkeana) using the same procedure as the one used with bonobos to see whether they would also exhibit a hinderer preference. Subjects did not prefer the helper over the hinderer (or vice versa). The low attentional level observed in our subjects suggests a lack of interest in the video stimuli. This finding relates to more general questions regarding how animals perceive abstract animated onscreen stimuli and the relevance of the hill paradigm in investigating prosocial preferences. Studies using various experimental paradigms with conspecifics or human actors as social agents are needed to investigate further the social evaluation of prosocial behaviours in Tonkean macaques, bonobos, and other primates.

animal behavior and cognition↗

bioRxiv2024

Idiosyncrasy in gestural communication: a case study of hand-clapping in a Barbary macaque (Macaca sylvanus)

While it is well established that apes invent or individually learn new gestures, cases of development and use of novel gestures in monkeys are more rarely described. We report a case of a novel, idiosyncratic gesture in a Barbary macaque (Macaca sylvanus) at La Foret des Singes, Rocamadour, France. One adult male, Jomanix, was observed hand-clapping. To our knowledge, hand-clapping has never been described before in this species. To hand-clap, the male briefly shifted his weight onto his legs, lifted his upper body, and clapped both hands together. We recorded 30 instances of hand-clapping. Twenty-five of these hand-claps occurred in combination with other agonistic signals, such as lunges and open mouth threats. Recipients either responded with counter-aggression (N = 9) or a submissive response (N = 16). In five of the 30 events, the context was unclear. These observations suggest that the gesture constitutes an agonistic signal. According to the staff at La Foret des Singes, the hand-clapping may have been copied from staff members who occasionally hand-clap to shoo the animals away from areas where they were not supposed to be, but that notion remains speculative. In the meantime, another subject from the same group reportedly started to hand-clap, but the subject had passed away before we could document the behaviour. The observations show that Jomanix can flexibly combine a novel gesture with other established communicative signals. The hand-clap is goal-directed and fulfils the criteria for first-order intentional communication. This case, as well as anecdotal reports from a Tonkean macaque (Macaca tonkeana) hand-clapping to get attention, reveals greater flexibility in the gestural communication of this genus than previously assumed but also underscores that social learning of the production of communicative gestures occurs rarely in this taxon.

animal behavior and cognition↗

bioRxiv2024

Choose your partner: Social evaluation of skilfulness at cooperative co-action tasks in Tonkean macaques (Macaca tonkeana)

Social evaluation - inferring individual characteristics of others from their past behaviours - is an adaptive strategy that helps to inform social decisions. However, how nonhuman primates form and use impressions about others to select their social partners strategically is still unclear. In this study, we investigated whether Tonkean macaques, Macaca tonkeana, can spontaneously use information, acquired by observation, to choose the optimal partners for cooperation in two co-action tasks from the same domain. The subjects (N=5) did not prefer to cooperate with the skilful partner compared to the unskilled partner, irrespective of the task or how much attention they paid to the partners actions solving a solo version of one task prior to the test. The probability of optimal choices did not increase through trials either, indicating no learning by experience with the partners across the 16 test trials. Our results contradict findings of previous studies that tested monkeys in different domains of competence and contexts, and thus encourage further investigation on monkeys social evaluation abilities. Our experimental design presents a promising way to investigate different contexts, the inter-individual differences, the different types of social information involved, and the cognitive mechanisms underlying social evaluation and partner selectivity in nonhuman primates.

animal behavior and cognition↗