<figure><img src="image_1.png" /></figure>

HAL
open science

# Human language emergence and mother-infant communication in primates: A developmental and comparative study

Mawa Dafreville, Charlotte Canteloup, Erica van de Waal

► To cite this version:

Mawa Dafreville, Charlotte Canteloup, Erica van de Waal. Human language emergence and mother-infant communication in primates: A developmental and comparative study. Culture Conference, Feb 2024, Zürich, Switzerland, Switzerland. [hal-04757634](https://hal.science/hal-04757634v1)

HAL Id: hal-04757634

https://hal.science/hal-04757634v1

Submitted on 29 Oct 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

Public Domain
# Human language emergence and mother-infant communication in primates: A developmental and comparative study

Mawa Dafreville*<fnref n="1" />,<fnref n="2" />, Charlotte Canteloup<fnref n="2" />,<fnref n="3" />, Erica van de Waal<fnref n="1" />,<fnref n="2" />,<fnref n="4" />

From the *evo-devo* perspective, some hypotheses about the origins of language suggest that the volitional control of the voice may have appeared in the human lineage to maintain parental attention and investment. Our investigation aimed at expanding our knowledge of the primates' communication development within this theoretical perspective. We quantified the infants' attention-sensitive signaling indexed to maternal visual attention and inattention in mother-infant dyads of humans (N=30) and wild chimpanzees (N=11). The naturalistic observation of attention-sensitive signalling was tested through *unimodal* and *cross-modal* adjustments, respectively defined by the capacity of young primates to address visually inattentive mothers (i) by avoiding silent-visual signals (i.e., communication mismatches) and/or (ii) favouring communication matches through audible-or-contact signals. Human infants adjusted their silent-visual signals (i.e., *unimodal* adjustment) before adjusting their audible and tactile ones (i.e., *cross-modal* adjustment) during development while the young chimpanzees displayed a reverse order of emergence. Regarding some *evo-devo* hypotheses, these results may therefore support the plausibility of a putative human specificity in the development of signals use within mother-infant multimodal interaction. Indeed, audible communication, prominent in mature individuals in humans, may depend on more socio-ecological environment and thus may take longer to be mastered and adjusted than other signals. However, these finding calls for further comparative and acoustic analyses with other species as well as other human populations to refine these hypotheses with empirical data. Along these lines, vervet monkeys are a species of interest since (i) they use both gestures and vocalisations, with prominent vocal use, (ii) young vervet monkeys may require social learning in their vocal development and (iii) this species show different behavioural phenotypes depending on their group. This investigation will be conducted on wild juvenile vervet monkeys (N≥20) belonging to different groups and discussed within an evo-devo framework related to the evolution of communication within the primate lineage.

**Application for an oral presentation in-person**

<footnote n="1">¹Department of Ecology and Evolution, University of Lausanne, Switzerland</footnote>

<footnote n="2">²Center of Primatology, University of Strasbourg, France</footnote>

<footnote n="3">³Laboratory of Cognitive and Adaptive Neurosciences, CNRS, UMR 7364, University of Strasbourg, France</footnote>

<footnote n="4">⁴Inkawu Vervet Project, Mawana Game Reserve, Swart Mfolozi, KwaZulu Natal, South Africa</footnote>

<footnote>*Presenter (She/Her)</footnote>