Gorillas are right-handed for their most frequent intraspecific gestures

doi:10.1016/j.anbehav.2016.06.008

Animal Behaviour

Volume 118, August 2016, Pages 165-170

https://doi.org/10.1016/j.anbehav.2016.06.008 Get rights and content

Highlights

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Gorillas are right handed for the most frequent intraspecific gestures considered.
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Laterality bias at the population level evidenced for intraspecific interactions.
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Gestural laterality would be a precursor of the language left-brain specialization.

Investigations of intraspecific laterality of primates' gestural communication aim to shed light on the evolutionary origins of human handedness and language. Currently, little is known concerning laterality of gestures for purely intraspecific communication. As far as we know, this study is the first to assess laterality of gorillas' purely intraspecific gestures at the population level. We analysed hand use in dyadic interactions in 35 gorillas, Gorilla gorilla gorilla, living in three groups in captivity focusing on their most frequent communication gesture types. We revealed a right-hand bias at the population level for the majority of the most frequent gestures recorded. Our findings support the evolutionary theories predicting that population level asymmetry should be found in fitness-relevant social behaviours and could be explained by an evolutionarily stable strategy based on intraspecific interactions. They also agree with reports evidencing predominant right-hand use for gestural communication by nonhuman primates and suggesting that gestural laterality is a precursor of the left-hemispheric lateralization of language.

Section snippets

Subjects

Thirty-five lowland gorillas, G. g. gorilla, raised under seminatural conditions were observed at three zoos: La Vallée des Singes (France), Apenheul Primate Park and Burgers' Zoo (The Netherlands). Age categories of subjects were based mainly on Breuer, Hockemba, Olejniczak, Parnell, and Stokes (2009) categories for infants (0–3 years), juveniles (4–6 years) and adolescents (7–11 years) and on Stoinski, Lukas, and Kuhar (2013) categories for young adults (12–20 years) and mature adults (>20

Results

We recorded 16 801 occurrences of gestures by our 35 subjects during 651 h of observation. After we applied the statistical criteria required for performing binomial tests (Siegel & Castellan, 1988), 16 471 occurrences of gestures were retained for descriptive statistics and related analyses. The mean number of gesture occurrences per subject was 470.60 (minimum = 6, maximum = 1771, SD = 504.34).

To assess gestural laterality at the population level, we analysed each of the 16 gestures separately.

Discussion

This study aimed to improve our understanding of gorillas' gestural laterality by analysing the most frequent gesture types of their natural repertoire. To achieve this goal, we evaluated gestural laterality bias at the population level.

Gorillas presented a right-hand bias at the population level for the majority (nine of 16) of their most frequent intraspecific gestures. As far as we know, the present study is the first to evidence a right-hand bias at the population level for gorillas'

Acknowledgments

We are very grateful to all the keepers and collaborators of the La Vallée des Singes zoo (France), the Apenheul zoo and the Burgers' zoo (Netherlands) and particularly Jean-Pascal Guéry, Frank Rietkerk and Wineke Schoo for allowing us to study their gorilla groups, as well as for their friendliness and helpfulness. We are also indebted to Amandine Chapelain for her advice about the design of the observation protocol, to Caroline Coste for entering some of the data as well as to Ann Cloarec for

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Asymmetries that are observed at the population level in social honeybees are present only at the individual level in solitary mason bees (Anfora, Frasnelli, Maccagnani, Rogers, & Vallortigara, 2010 and see also; Anfora et al., 2011; Rigosi et al., 2015; Frasnelli et al., 2011, 2014, 2010, Frasnelli and Vallortigara, 2017; Rigosi et al., 2011), apart from occasions on which the mason bees do interact socially, as in agonistic interactions (Rogers, Frasnelli, & Versace, 2016). In general, it seems very well documented that population lateralization is more likely to be observed in social contexts in both vertebrates (Lemaire, Viblanc, & Jozet-Alves, 2019; Prieur, Pika, Barbu, & Blois-Heulin, 2016; Robins, Goma, Quine, & Phillips, 2018; Stor, Rebstock, García Borboroglu, & Boersma, 2019; Williams & Anderson, 2012), and invertebrates (Benelli et al., 2017; Romano et al., 2016, 2015; Schnell, Jozet-Alves, Hall, Radday, & Hanlon, 2019; Frasnelli et al., 2012a, b; Frasnelli, Ponte, Vallortigara, & Fiorito, 2019; though see for a possible exception; Versace, Caffini, Werkhoven, & de Bivort, 2019). However, the hypothesis has also incurred some misunderstanding, such as the idea that the presence of lateralization would depend only on categorizing a species as social or non-social (see for a discussion Frasnelli & Vallortigara, 2017).
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View full text

Gorillas are right-handed for their most frequent intraspecific gestures

Highlights

Section snippets

Subjects

Results

Discussion

Acknowledgments

Behavioural Brain Research

Cortex

Neuroscience & Biobehavioral Reviews

Journal of Human Evolution

Behavioural Brain Research

Cortex

Animal Behaviour

Brain and Language

Applied Animal Behaviour Science

An introduction to human evolutionary anatomy

Observational study of behavior: Sampling methods

Behaviour

Examining the relationship between degree of handedness and degree of cerebral lateralization for processing facial emotion

Neuropsychology

Physical maturation, life-history classes and age estimates of free-ranging western gorillas-insights from Mbeli Bai, Republic of Congo

American Journal of Primatology

Manual dexterity in the gorilla, bimanual and digit role differentiation in a natural task

Animal Cognition

Asymmetric Broca's area in great apes

Nature

Hand preferences in bonobos (Pan paniscus) for a variety of actions: spontaneous daily actions (non-social and social), bimanual coordination (‘tube task’), tool-use (‘termite fishing’) and induced gestures (‘begging’)

Evolutionary origins of human handedness: Evaluating contrasting hypotheses

Animal Cognition

From hand to mouth: The origins of language

The evolution and genetics of cerebral asymmetry

Philosophical Transactions of the Royal Society of London B: Biological Sciences

Clapping in chimpanzees: Evidence of exclusive hand preference in a spontaneous, bimanual gesture

American Journal of Primatology

Laterality of hand function in naturalistically housed chimpanzees (Pan troglodytes)

Laterality

Target animacy influences gorilla handedness

Animal Cognition

Gestural communication of the gorilla (Gorilla gorilla): Repertoire, intentionality and possible origins

Animal Cognition

Intraspecific competition and coordination in the evolution of lateralization

Philosophical Transactions of the Royal Society of London B

The evolution of brain lateralization: A game-theoretical analysis of population structure

Proceedings of the Royal Society B: Biological Sciences

Hand preference for visually-guided reaching in human infants and adults

Handedness in captive gorillas (Gorilla gorilla)

Primates

Laterality in the gestural communication of wild chimpanzees

Annals of the New York Academy of Sciences

Culture in bonobos? Between-species and with-species variation in behavior

Current Anthropology

Intra- and intersexual aggression by bonobos in the context of mating

Behaviour

Behavioral laterality in captive bonobos (Pan paniscus)

Journal of Comparative Psychology

The use of bouts and frequencies in the evaluation of hand preferences for a coordinated bimanual task in chimpanzees (Pan troglodytes): An empirical study comparing two different indices of laterality

Journal of Comparative Psychology

Hand use and gestural communication in chimpanzees (Pan troglodytes)

Journal of Comparative Psychology

Handedness for manual gestures in great apes: A meta-analysis

Factors influencing the prevalence and handedness for throwing in captive chimpanzees (Pan troglodytes)

Journal of Comparative Psychology