Multicomponent and multisensory communicative acts in orang-utans may serve different functions

Marlen Fröhlich,Maria A Van Noordwijk,Colin Wagner,Caroline Fryns,Carel P Van Schaik,Natasha Bartolotta,Tatang Mitra Setia,Marvin Jaffrezic,Laurene Momon

doi:10.1038/s42003-021-02429-y

Marlen Fröhlich, Maria A Van Noordwijk + Show 7 more

Open Access

https://doi.org/10.1038/s42003-021-02429-y

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Abstract

From early infancy, human face-to-face communication is multimodal, comprising a plethora of interlinked communicative and sensory modalities. Although there is also growing evidence for this in nonhuman primates, previous research rarely disentangled production from perception of signals. Consequently, the functions of integrating articulators (i.e. production organs involved in multicomponent acts) and sensory channels (i.e. modalities involved in multisensory acts) remain poorly understood. Here, we studied close-range social interactions within and beyond mother-infant pairs of Bornean and Sumatran orang-utans living in wild and captive settings, to examine use of and responses to multicomponent and multisensory communication. From the perspective of production, results showed that multicomponent acts were used more than the respective unicomponent acts when the presumed goal did not match the dominant outcome for a specific communicative act, and were more common among non-mother-infant dyads and Sumatran orang-utans. From the perception perspective, we found that multisensory acts were more effective than the respective unisensory acts, and were used more in wild compared to captive populations. We argue that multisensory acts primarily facilitate effectiveness, whereas multicomponent acts become relevant when interaction outcomes are less predictable. These different functions underscore the importance of distinguishing between production and perception in studies of communication.

Highlights

From early infancy, human face-to-face communication is multimodal, comprising a plethora of interlinked communicative and sensory modalities
We found that individuals used multisensory communicative acts on average in 25% of observed cases, of which 15% were uni-component and about 10% were multicomponent
We found that communicative acts contained salient visual components in 49% of cases, tactile components in 75%, auditory components in 3%, and seismic components in 1%

Summary

Introduction

Human face-to-face communication is multimodal, comprising a plethora of interlinked communicative and sensory modalities. We argue that multisensory acts primarily facilitate effectiveness, whereas multicomponent acts become relevant when interaction outcomes are less predictable These different functions underscore the importance of distinguishing between production and perception in studies of communication. 1234567890():,; Human face-to-face communication is a multimodal phenomenon: our everyday speech is embedded in an interactional exchange of coordinated visual, auditory, and often even tactile signals Some parts of these complex displays are intrinsically coupled due to the effort of vocal production (such as mouth movement accompanying speech sounds), but others are flexible (e.g. gaze and co-speech gestures). The theoretical and empirical differences between these combination types are often ignored in comparative research[12,17], but addressing them would be key to draw conclusions about homologous features in the human/ape communication system[21]

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