Olive baboons, Papio anubis, adjust their visual and auditory intentional gestures to the visual attention of others

International audienceAlthough nonhuman primates' gestural communication is often considered to be a likely precursor of human language, the intentional properties in this communicative system have not yet been entirely elucidated. In particular, little is known about the intentional nature of monkeys' gestural signalling and related social understanding. We investigated whether olive baboons can (1) adjust their requesting gestures to the visual attention of the experimenter with special emphasis on the state of the eyes (open versus closed), and (2) flexibly tailor visual and auditory-based gestures to elaborate their communication as a function of whether or not the experimenter can see them. Using a food-requesting paradigm, we found monkeys able to favour either visual or auditory-based requesting gestures to match the experimenter's visual attention. Crucially, when the human was not visually attending, they silenced visual gestures to some extent but performed more attention-getting gestures. This is, to our knowledge, the first report of monkeys elaborating attention-getting signals to compensate for communication breakdown. Gestural communication was also supported by gaze alternation between the experimenter's face and the food, especially when the human was visually attending. These findings offer evidence that olive baboons understand the state of the eyes in others' visual attention and use requesting gestures intentionally. They emphasize that Old World monkeys shift to acoustic communication when the recipient is not visually attending. In contrast to that of human infants and great apes, this acoustic communication is purely gestural, not vocal

Survival is linked with reaction time and spatial memory in African striped mice

International audienceStudying the association between fitness and cognition in free-living animals is a fundamental step in the elucidation of the evolution of cognition. We assessed whether survival until the onset of the breeding season was related to reaction time or spatial memory in the African striped mouse Rhabdomys pumilio, a rodent that has to survive summer drought before breeding. We tested a total of 90 individuals at the beginning of summer. Female survival was related to a faster response to predation stimuli. Male survival increased with greater spatial memory, possibly because it is important for males to remember the configuration of the environment during dispersal. This study revealed that individual variation in reaction time and spatial memory can be related to survival probability, which is important for understanding the selection pressures acting on basic cognitive traits

Empreintes optiques intra-orales (comparaison de deux systèmes)

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocSudocFranceF

Latéralité manuelle, actes de préhension et gestes communicatifs (de l importance de considérer les variations entre individus et entre espèces)

La latéralité manuelle varie entre les individus et semble être fonction de la nature et de la complexité des tâches manuelles. Dans un premier temps, nous avons cherché à caractériser plus finement le lien existant entre niveau de complexité et caractéristiques individuelles et spécifiques. L'analyse de la latéralité manuelle exprimée pour des actes de préhension précise nécessitant une coordination bimanuelle ou réalisés en absence de guidage visuel, chez les singes de Brazza et les mangabés à collier, a révélé des variations entre adultes / juvéniles, mâles / femelles et aussi entre espèces des patterns de latéralité manuelle d'une part et des stratégies employées et/ou des performances d'autre part. Notre étude suggère que les aptitudes motrices, perceptuelles et cognitives des individus pourraient moduler la gestion de tâches manuelles complexes et ainsi entraîner des différences inter-individuelles et inter-spécifiques de la latéralité manuelle. Nos investigations chez les toupayes de Bélanger, une espèce phylogénétiquement proche des primates, soulignent quant à elles l'impact de la pression de prédation et du degré de socialité sur la force de latéralité manuelle. Dans un second temps, nous avons examiné la latéralité manuelle exprimée pour la production de gestes de quémande chez les mangabés à collier et les mones de Campbell. Ces travaux ont révélé une interaction entre aptitudes communicatives et préférences manuelleschez les mangabés à collier, puisque seuls les individus présentant les meilleures aptitudes référentielles montraient une utilisation plus importante de la main droite pour la production de gestes communicatifs comparativement à l'exécution d'actes de préhension unimanuelle. Chez les mangabés, la production de gestes communicatifs dirigés vers une audience semble ainsi être contrôlée par des aires cérébrales localisées dans l'hémisphère gauche; ces résultats penchent en faveur d'une origine gestuelle du langage.Manual laterality differs between individuals and seems to be related to both the type and complexity of the manual tasks. First, we aimed to characterize more finely the relationship between task complexity and individual and specific traits. The analysis of manual laterality exhibited for precise grasping requiring bimanual coordination or involving a lack of visual guidance, in de Brazza's monkey and red-capped mangabeys, revealed differences between adults/juveniles, males/females and also between species in the patterns of manual laterality on one hand and in strategy use and/or performance on the other hand. Out study suggests that motor, perceptual and cognitive abilities may affect the processing of complex manual tasks and thus lead to inter-individual and inter-specific variations in manual laterality. Our investigations in the Northern tree shrews, a species phylogenetically close to primates, underlined a potentiel influence of predation pressure and sociality on the strength of manual laterality. Second, we assessed manual laterality exhibited for the production requesting gestures in red-capped mangabeys and Campbell's monkeys. This research showed a an interaction between communicative abilities and hand preferences in red-capped mangabeys since only the individuals possessing the greatest referential abilities increased right-hand use for the production of communicative gestures compared to unimanual grasping actions. In mangabeys, the production of requesting gestures directed toward an audience might be controlled by left-hemisphere cerebral areas, this finding points to a gestural origin of language. Overall, our results stress the importance to consider inter-individual and inter-specific differences for the study of manual laterality and to strengthen the investigation of manual activities involved in social interactions.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Seasonal variation in attention and spatial performance in a wild population of the African striped mouse (Rhabdomys pumilio)

International audienceCognitive flexibility describes the reversiblechanges of cognition in response to environmental changes.Although various environmental factors such as temperature,photoperiod and rainfall change seasonally, seasonalvariation in cognitive performance has been reported inmerely a few birds and mammals. We assessed whethercognitive performance in a wild population of Africanstriped mice Rhabdomys pumilio, from the SucculentKaroo semidesert of South Africa, differed between summerand winter. In order to measure cognitive performance,striped mice were trapped in the field, tested under laboratoryconditions at our research station and returned to thefield within 5 h. We measured attention and spatial memoryusing the standardized orientation response test and theBarnes maze test. Males tested during summer orientedfaster toward a predator-stimulus but made more errors andtook longer to locate a shelter than males tested duringwinter. In contrast, females’ performance did not differbetween the two seasons. We discuss how the faster orientationin males during winter might be the consequenceof lower temperatures and/or prolonged food restriction.We suggest that the enhancement of spatial performanceduring winter might be due to a greater motivation forfuture dispersal in male striped mice, as spring representsthe breeding season

Manual laterality and strategy use for a coordinated bimanual task requiring precise and power grip in guenons and mangabeys

International audienceBimanual tasks have been repeatedly shown to elicit manual asymmetries supposed to reflect hemispheric specialization. And yet, a coordinated bimanual task, the BOX task, appears to be inefficient in detecting biases of hand preferences. The BOX task involves two sequential actions requiring a precise grip, lift the lid of a box and grasp a small item inside the box (while holding the lid). In the present study, we compared manual laterality exhibited for the classic bimanual BOX task and for a unimanual BOX task in 11 De Brazza's monkeys (Cercopithecus neglectus) and 19 red-capped mangabeys (Cercocebus torquatus). In addition, we assessed strategy use for solving the bimanual BOX task. We found that left-hand use for grasping the item was higher in the BOX-bimanual task than in the BOX-unimanual task. We propose that this increase in left-hand use for grasping the item results from both a hemispheric specialization for lifting the lid and an advantage in using a skillful strategy. Indeed, we revealed (1) group-level right biases for lifting the lid and (2) a complete differentiation between the roles of the two hands in subjects showing a left-hand preference for grasping the item. Finally, the bimanual BOX task showed age differences in the two species, either in manual laterality for grasping the item or in strategy use. This study provides additional evidence that manual laterality might be sensitive to maturational factors and characteristics of the bimanual tasks such as the order and the features of sequential actions

Les gestes de quémande des mangabés à collier : communication interspécifique ou simple conditionnement instrumental ?

National audienc

What the Bishop QHP task can tell us about manual laterality of guenons and mangabeys?

International audienc

Communication gestuelle chez les primates non humains : les gestes de quémande des mangabés à collier (Cercocebus torquatus) sont-ils influencés par l’état attentionnel des humains ?

National audienceAfin de déterminer les processus cognitifs qui sous-tendent la production de signaux de communication, il est indispensable de s’intéresser à leur contexte d’émission. On parle alors de signal fixé pour un signal émis en réponse à des stimulations précises de l’environnement, et de signal intentionnel pour un signal dont la production est flexible et interactive (i.e. ajustements par rapport au partenaire). Bien que les singes déploient une grande variété de signaux gestuels, la flexibilité d’usage de leurs gestes communicatifs reste peu étudiée. Nous avons donc choisi de nous intéresser à la production de ces gestes chez un singe de l’ancien monde, le mangabé à collier, lors d’interactions avec l’homme. Neuf mangabés (3 mâles, 6 femelles) ont tout d’abord été entrainés à solliciter un don de nourriture de la part d’un partenaire humain en effectuant un geste de quémande (extension du bras en direction d’un item alimentaire inaccessible). Nous avons ensuite testé la capacité de ces mangabés à moduler la production de ces gestes de quémande en fonction de l’état attentionnel de l’homme. Pour ce faire, nous avons fait varier l’orientation du corps, de la tête et des yeux de l’expérimentateur qui se tenait face au mangabé. Lorsque l’expérimentateur était de dos ou tournait la tête, les mangabés effectuaient moins de gestes de quémande, et la latence de quémande augmentait. Ces résultats suggèrent que les gestes de quémande des mangabés ne sont pas simplement émis en réponse à la présence conjointe d’un aliment inaccessible et d’un partenaire humain, mais que leur production est influencée par la capacité de ce dernier à les percevoir. Bien que cette étude ne permette pas de conclure que les mangabés utilisent leurs gestes de quémande de façon intentionnelle, elle est la première démonstration d’une production flexible d’un geste communicatif appris chez un singe de l’ancien monde