Year-end Sale % OFF 
Abstract
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.
Highlights
The evolutionary origins of language and speech remains a fundamental question in science
Successive calling, sometimes referred to antiphony, consisted of a temporal synchronization with no overlap of the call utterances between two consecutive callers (Fig. 1; see a typical sequence of vocal exchanges in the Supporting Audio File)
Vocal exchanges have been reported in the context of long-distance communication in chimpanzees[61] and bonobos[62], as a means to coordinate their movement between parties
Summary
The evolutionary origins of language and speech remains a fundamental question in science. Vocal exchange patterns are influenced by social factors in non-human primates. Shared primitive forms of vocal turn-taking within non-human primate species might suggest an ancient evolutionary origin[1,34]. More investigations among great ape species, our closest, highly social, relatives, are 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]. Social influences on the acoustic patterns of calls can be assessed by examining the rate of vocal sharing, defined as the production rate of vocal ‘variants’ between individuals at a given time[26]. We attempted to identify features that are already known to characterize both monkey call exchanges and human conversations in a great ape species, the bonobo (Pan paniscus). We predicted more frequent vocal interactions and a higher rate of vocal exchanges between preferred social partners
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
