Social coordination in animal vocal interactions.pdf

Frontiers in Psychology, 2015

Turn-taking in conversation appears to be a common feature in various human cultures and this universality raises questions about its biological basis and evolutionary trajectory. Functional convergence is a widespread phenomenon in evolution, revealing sometimes striking functional similarities between very distant species even though the mechanisms involved may be different. Studies on mammals (including non-human primates) and bird species with different levels of social coordination reveal that temporal and structural regularities in vocal interactions may depend on the species' social structure. Here we test the hypothesis that turn-taking and associated rules of conversations may be an adaptive response to the requirements of social life, by testing the applicability of turn-taking rules to an animal model, the European starling. Birdsong has for many decades been considered as one of the best models of human language and starling songs have been well described in terms of vocal production and perception. Starlings do have vocal interactions where alternating patterns predominate. Observational and experimental data on vocal interactions reveal that (1) there are indeed clear temporal and structural regularities, (2) the temporal and structural patterning is influenced by the immediate social context, the general social situation, the individual history, and the internal state of the emitter. Comparison of phylogenetically close species of Sturnids reveals that the alternating pattern of vocal interactions varies greatly according to the species' social structure, suggesting that interactional regularities may have evolved together with social systems. These findings lead to solid bases of discussion on the evolution of communication rules in relation to social evolution. They will be discussed also in terms of processes, at the light of recent neurobiological findings.

Scientific Reports

the origin of human speech is still a hotly debated topic in science. evidence of socially-guided acoustic flexibility and proto-conversational rules has been found in several monkey species, but is lacking in social and cooperative great apes. Here we investigated spontaneous vocal interactions within a peaceful context in captive bonobos to reveal that vocal interactions obey temporally and social rules. Dyadic vocal interactions were characterized by call overlap avoidance and short inter-call intervals. Bonobos preferentially responded to conspecifics with whom they maintained close bonds. We also found that vocal sharing rate (production rate of shared acoustic variants within each given dyad) was mostly explained by the age difference of callers, as other individual characteristics (sex, kinship) and social parameters (affinity in spatial proximity and in vocal interactions) were not. Our results show that great apes spontaneously display primitive conversation rules guided by social bonds. The demonstration that such coordinated vocal interactions are shared between monkeys, apes and humans fills a significant gap in our knowledge of vocal communication within the primate phylogeny and highlights the universal feature of social influence in vocal interactions. The evolutionary origins of language and speech remains a fundamental question in science. In particular, whether clues to the origins of speech are present in nonhuman primate communication remains a hotly debated topic 1-4. Despite the diversity of social cultures and languages in humans, universal features in conversations are found across all languages, such as the avoidance of overlapping and a minimum gap between turns 5-8. Orderly vocal exchanges (antiphony between two or more animals or duets within male-female pairs 9) have been found across the primate order: from lemurs 10 , to New World monkeys 11-15 , Old World monkeys 16 and lesser apes 17,18. Vocal turn-taking appears to be associated with social life and cooperation capacities 1,2,5,9,19-21. It is thought to maintain and reinforce social bonds between individuals (e.g. in non-human primates 10,22), enable the extraction of information in the absence of overlap (e.g. 23 but see 24) and reduce stress as in the case of social grooming 25. Vocal exchange is "a characteristic communication style in which a sender produces a vocalization to address a receiver, and the receiver emits a call in response within a brief interval" (cited from 26). Vocal exchange patterns are influenced by social factors in non-human primates. 'Interlocutors' are not randomly selected, and preference is given to elders 11,27-29 , social allies 12,14,22 or dominant individuals 30,31. The attention of the audience also influences vocal outputs leading to persistence (repetition of calls) and elaboration (changes in the acoustic structure of calls) in situations where no response has been received 32,33. Shared primitive forms of vocal turn-taking within non-human primate species might suggest an ancient evolutionary origin 1,34. Surprisingly, however, studies based on great apes are scarce and controversial. No evidence of spontaneous vocal coordinated exchanges has been found in wild chimpanzees 35 , who display complex social interactions and cooperative abilities 36. Indeed, Arcadi 35 found that chimpanzees do not "respond" to the majority of calls they heard (within 5 sec), and that instead, bonded males tend to chorus together, matching each-other's pant hoots 37,38. Nevertheless, a recent study in great apes found for the first time that captive gorillas display some rule-governed call exchanges 31. Relying on our current knowledge, vocal turn-taking is thus reported across phylogenetically distant species (monkeys and more generally in some social mammals such as African elephants 39 , bottlenose dolphins 40 , bats 41,42 , naked mole-rats 43) but with some apparent discontinuities among great apes. More investigations among great ape species, our closest, highly social, relatives, are thus necessary in order to ascertain if vocal-turn taking behavior is as a result of convergent evolution (analogies as adaptations to similar social requirements) or is shared ancestry (homologies which are inheritance behaviours) 34 .

Annals of the New York Academy of Sciences

The study of human language is progressively moving toward comparative and interactive frameworks, extending the concept of turn-taking to animal communication. While such an endeavor will help us understand the interactive origins of language, any theoretical account for cross-species turn-taking should consider three key points. First, animal turn-taking must incorporate biological studies on animal chorusing, namely how different species coordinate their signals over time. Second, while concepts employed in human communication and turn-taking, such as intentionality, are still debated in animal behavior, lower level mechanisms with clear neurobiological bases can explain much of animal interactive behavior. Third, social behavior, interactivity, and cooperation can be orthogonal, and the alternation of animal signals need not be cooperative. Considering turn-taking a subset of chorusing in the rhythmic dimension may avoid overinterpretation and enhance the comparability of future empirical work.

Frontiers in Psychology, 2013

Social factors play a key role in the structuring of vocal repertoires at the individual level, notably in non-human primates. Some authors suggested that, at the species level too, social life may have driven the evolution of communicative complexity, but this has rarely been empirically tested. Here, we use a comparative approach to address this issue. We investigated vocal variability, at both the call type and the repertoire levels, in three forest-dwelling species of Cercopithecinae presenting striking differences in their social systems, in terms of social organization as well as social structure. We collected female call recordings from twelve De Brazza's monkeys (Cercopithecus neglectus), six Campbell's monkeys (Cercopithecus campbelli) and seven red-capped mangabeys (Cercocebus torquatus) housed in similar conditions. First, we noted that the level of acoustic variability and individual distinctiveness found in several call types was related to their importance in social functioning. Contact calls, essential to intra-group cohesion, were the most individually distinctive regardless of the species, while threat calls were more structurally variable in mangabeys, the most "despotic" of our three species. Second, we found a parallel between the degree of complexity of the species' social structure and the size, diversity, and usage of its vocal repertoire. Mangabeys (most complex social structure) called twice as often as guenons and displayed the largest and most complex repertoire. De Brazza's monkeys (simplest social structure) displayed the smallest and simplest repertoire. Campbell's monkeys displayed an intermediate pattern.

Proceedings of the Royal Society B: Biological Sciences

Language, humans’ most distinctive trait, still remains a ‘mystery’ for evolutionary theory. It is underpinned by a universal infrastructure—cooperative turn-taking—which has been suggested as an ancient mechanism bridging the existing gap between the articulate human species and their inarticulate primate cousins. However, we know remarkably little about turn-taking systems of non-human animals, and methodological confounds have often prevented meaningful cross-species comparisons. Thus, the extent to which cooperative turn-taking is uniquely human or represents a homologous and/or analogous trait is currently unknown. The present paper draws attention to this promising research avenue by providing an overview of the state of the art of turn-taking in four animal taxa—birds, mammals, insects and anurans. It concludes with a new comparative framework to spur more research into this research domain and to test which elements of the human turn-taking system are shared across species a...

Naturwissenschaften, 2019

Vocal communication plays an important role in the regulation of social interactions and the coordination of activities in many animal species. Synchrony is an essential part of the establishment and maintenance of pair bonds, but few reports have investigated decision making at the pair level. We investigated temporal characteristics of call exchanges in palewinged starlings (Onychognathus nabouroup) that could predict whether one, two, or neither members of a pair would take off. Our analysis of these interactions revealed that the overall rhythm of a call exchange, as well as the acceleration towards the end of an interaction, were significantly associated with the type of behavioural outcome. Faster rhythms were associated with higher probabilities that both birds would fly away. Our results confirm the findings of previous studies showing that higher rates of alarm calls indicate imminent departure and highlight the relationship between temporal features of vocal interactions and their outcome.

HAL (Le Centre pour la Communication Scientifique Directe), 2017

Vocal communication plays an important role in the regulation of social interactions and the coordination of activities in many animal species. Synchrony is an essential part of the establishment and maintenance of pair bonds, but few reports have investigated decision-making at the pair level. We investigated temporal characteristics of call exchanges in pale-winged starlings (Onychognathus nabouroup) that could predict whether one, two, or neither members of a pair would take off. Our analysis of these interactions revealed that the overall rhythm of a call exchange, as well as the acceleration towards the end of an interaction, were significantly associated with the type of behavioural outcome. Faster rhythms were associated with higher probabilities that both birds would fly away. Our results confirm the findings of previous studies showing that higher rates of alarm calls indicate imminent departure and highlight the relationship between temporal features of vocal interactions and their outcome.

Biology Letters, 2005

Understanding the rules that link communication and social behaviour is an essential prerequisite for discerning how a communication system as complex as human language might have evolved. The comparative method offers a powerful tool for investigating the nature of these rules, since it provides a means to examine relationships between changes in communication abilities and changes in key aspects of social behaviour over evolutionary time. Here we present empirical evidence from phylogenetically controlled analyses indicating that evolutionary increases in the size of the vocal repertoire among non-human primate species were associated with increases in both group size and time spent grooming (our measure of extent of social bonding).

Springer eBooks, 2006

Semiotica, 1997

Conversation, coordination and vertebrate communication sets out a framework making it possible to compare how communicative activity is organized in arrange of species. While recognizing that humans explain language-systems, emphasis falls on biologically simpler patterns and, above all, interindividual coordination. To capture cross-species parallels, it begins by with differences between ‘using’ a language-system and taking part in the dialogical events of a conversation. Once this is clear, phonetic observations backed up with a acoustic measurements suffice to show close resemblance between how activity is managed and assessed in humans and other species. Human talk uses similar principles of organization to not only, say, the duetting of buff-breated wrens but also how many species of vertebrate coordinate around real-time activity.