Variable expression of linguistic laws in ape gesture : a case study from chimpanzee sexual solicitation
Abstract
Two language laws have been identified as consistent patterns shaping animal behaviour, both acting on the organizational level of communicative systems. Zipf's law of brevity describes a negative relationship between behavioural length and frequency. Menzerath's law defines a negative correlation between the number of behaviours in a sequence and average length of the behaviour composing it. Both laws have been linked with the information-theoretic principle of compression, which tends to minimize code length. We investigated their presence in a case study of male chimpanzee sexual solicitation gesture. We failed to find evidence supporting Zipf's law of brevity, but solicitation gestures followed Menzerath's law: longer sequences had shorter average gesture duration. Our results extend previous findings suggesting gesturing may be limited by individual energetic constraints. However, such patterns may only emerge in sufficiently large datasets. Chimpanzee gestural repertoires do not appear to manifest a consistent principle of compression previously described in many other close-range systems of communication. Importantly, the same signallers and signals were previously shown to adhere to these laws in subsets of the repertoire when used in play; highlighting that, in addition to selection on the signal repertoire, ape gestural expression appears shaped by factors in the immediate socio-ecological context.
Citation
Safryghin , A , Cross , C P , Fallon , B L A , Heesen , R , Ferrer-i-Cancho , R & Hobaiter , C 2022 , ' Variable expression of linguistic laws in ape gesture : a case study from chimpanzee sexual solicitation ' , Royal Society Open Science , vol. 9 , no. 11 , 220849 . https://doi.org/10.1098/rsos.220849
Publication
Royal Society Open Science
Status
Peer reviewed
ISSN
2054-5703Type
Journal article
Rights
Copyright © 2022 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
Description
Funding: European Commission - European Union’s 8th Framework Programme, Horizon 2020.Collections
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