Humans are strongly lateralized for manual gestures at both individual and population levels. In contrast, the laterality bias in primates is less strong, leading some to suggest that lateralization evolved after the Pan and Homo lineages diverged. However, laterality in humans is also context-dependent, suggesting that observed differences in lateralization between primates and humans may be related to external factors such as the complexity of the social environment. Here we address this question in wild chimpanzees and examine the extent to (...) which the laterality of manual gestures is associated with social complexity. Right-handed gestures were more strongly associated with goal-directed communication such as repair through elaboration in response to communication failure than left-handed gestures. Right-handed gestures occurred in evolutionarily urgent contexts such as in interactions with central individuals in the network, including grooming reciprocity and mating, whereas left-handed gestures occurred in less-urgent contexts, such as travel and play. Right-handed gestures occurred in smaller parties and in the absence of social competition relative to left-handed gestures. Right-handed gestures increased the rate of activities indicating high physiological arousal in the recipient, whereas left-handed gestures reduced it. This shows that right- and left-handed gestures differ in cognitive and social complexity, with right-handed gestures facilitating more complex interactions in simpler social settings, whereas left-handed gestures facilitate more rewarding interactions in complex social settings. Differences in laterality between other primates and humans are likely to be driven by differences in the complexity of both the cognitive skills underpinning social interactions and the social environment. (shrink)

We call those gestures “instrumental” that can enhance certain thinking processes of an agent by offering him representational models of his actions in a virtual space of imaginary performative possibilities. We argue that pointing is an instrumental gesture in that it represents geometrical information on one’s own gaze direction, and provides a ritualized template for initiating gaze coordination and joint attention. We counter two possible objections, asserting respectively that the representational content of pointing is not constitutive, but derived from language, (...) and that pointing directly solicits gaze coordination, without representing it. We consider two studies suggesting that attention and spatial perception are actively modified by one’s own pointing activity: the first study shows that pointing gestures help children link sets of objects to their corresponding number words; the second, that adults are faster and more accurate in counting when they point. (shrink)

Language is a complex intentional, syntactical and referential system involving a left-hemispheric specialization of the brain in which some cerebral regions such as Broca’s and Wernicke’s areas play a key-role. Because nonhuman primates are phylogenetically close to humans, research on our primate cousins might help providing clues for reconstructing the features of our ancestral communicative systems. In the present paper, after emphasising the tight relation between gestures and language in humans, we underlie the specific significance of communicative gestures and of (...) the progressive control of the oro-facial system and the vocal tract in the course of the language evolution. For this purpose, we will then review the findings related to the features, the lateralization and brain correlates of both vocal and gestural systems in nonhuman primates. (shrink)

Numerous evolutionary linguists have indicated that human pointing behaviour might be associated with the evolution of language. At an ontogenetic level, and in normal individuals, pointing develops spontaneously and the onset of human pointing precedes as well as facilitates phases in speech and language development. Phylogenetically, pointing behaviour might have preceded and facilitated the evolutionary origin of both gestural and vocal language. Contrary to wild non-human primates, captive and human-reared nonhuman primates also demonstrate pointing behaviour. In this article, we analyse (...) the debates on pointing and its role it might have played in language evolution from a meta-level. From within an Applied Evolutionary Epistemological approach, we examine how exactly we can determine whether pointing has been a unit, a level or a mechanism in language evolution. (shrink)

Against the prior view that primate communication is based only on signal decoding, comparative evidence suggests that primates are able, no less than humans, to intentionally perform or understand impulsive or habitual communicational actions with a structured evaluative nonconceptual content. These signals convey an affordance-sensing that immediately motivates conspecifics to act. Although humans have access to a strategic form of propositional communication adapted to teaching and persuasion, they share with nonhuman primates the capacity to communicate in impulsive or habitual ways. (...) They are also similarly able to monitor fluency, informativeness and relevance of messages or signals through nonconceptual cues. (shrink)

Ape species-specific communication is grounded on the present, possesses some referential qualities and is mostly used to request objects or actions from others. Artificial systems of communication borrowed from humans transform apes' communicative exchanges by freeing them from the present (i.e. displaced reference) although requests still predominate as the main reason for communicating with others. Symbol use appears to enhance apes' relational abilities and their inhibitory control. Despite these substantial changes, it is concluded that even though artificial communication enhances thought (...) and enables its expression more openly, it does not create it or modify the motivation behind communicative exchanges. (shrink)

We review major developmental evidence on the continuity from action to gesture to word and sign in human children, highlighting the important role of caregivers in the development of multimodal communication. In particular, the basic issues considered here and contributing to the current debate on the origins and development of the language-ready brain are: (1) links between early actions, gestures and words and similarities in representational strategies; (2) importance of multimodal communication and the interplay between gestures and spoken words; (3) (...) interconnections between early actions, gestures and signs. The innovation of this report is in connecting these themes together to relevant findings from studies on children between 6 and 36 months of age and highlighting interesting parallels in studies on ape communicative behavior. (shrink)

The linguistic and cognitive sciences have severely underestimated the degree of linguistic diversity in the world. Part of the reason for this is that we have projected assumptions based on English and familiar languages onto the rest. We focus on some distortions this has introduced, especially in the study of semantics.

How does intentional communication evolve? Comparative studies can shed light on the evolutionary history of this relevant feature of human language and its distribution before modern humans. The current animal literature on intentional signaling consists mostly of ape gestural studies with evidence of subjects persisting and elaborating with sometimes arbitrary signals toward a desired outcome. Although vocalizations can also have such imperative qualities, they are typically produced in a functionally fixed manner, as if evolved for a specific purpose. Yet, intentionality (...) can sometimes transpire even in functionally fixed calls, for example, if production is adapted to audience composition. In this study, we carried out field experiments to test whether free-ranging sooty mangabeys adjusted snake alarm call production to their audiences. We found a positive relation between alarm call production and naïve individuals arriving, suggesting that callers attempted to influence their behaviors relative to the snake. Subjects called more with smaller audiences, if they had not heard other calls before, and if socially important individuals were in the area. We concluded that sooty mangabeys alarm call production can be explained as an active attempt to refer to an external event, rather than a mere readout of an internal state. (shrink)

We call those gestures “instrumental” that can enhance certain thinking processes of an agent by offering him representational models of his actions in a virtual space of imaginary performative possibilities. We argue that pointing is an instrumental gesture in that it represents geometrical information on one’s own gaze direction, and provides a ritualized template for initiating gaze coordination and joint attention. We counter two possible objections, asserting respectively that the representational content of pointing is not constitutive, but derived from language, (...) and that pointing directly solicits gaze coordination, without representing it. We consider two studies suggesting that attention and spatial perception are actively modified by one’s own pointing activity: the first study shows that pointing gestures help children link sets of objects to their corresponding number words; the second, that adults are faster and more accurate in counting when they point. (shrink)