Travel fosters tool use in wild chimpanzees

The research leading to these results has received funding from the People Programme (Marie Curie Actions) and from the European Research Council under the European Union’s Seventh Framework Programme for research, technological development and demonstration under REA grant agreement N°329197 awarded to TG, ERC grant agreement N°283871 awarded to KZ.Ecological variation influences the appearance and maintenance of tool use in animals, either due to necessity or opportunity, but little is known about the relative importance of these two factors. Here, we combined long-term behavioural data on feeding and travelling with six years of field experiments in a wild chimpanzee community. In the experiments, subjects engaged with natural logs, which contained energetically valuable honey that was only accessible through tool use. Engagement with the experiment was highest after periods of low fruit availability involving more travel between food patches, while instances of actual tool-using were significantly influenced by prior travel effort only. Additionally, combining data from the main chimpanzee study communities across Africa supported this result, insofar as groups with larger travel efforts had larger tool repertoires. Travel thus appears to foster tool use in wild chimpanzees and may also have been a driving force in early hominin technological evolution.Publisher PDFPeer reviewe

Wild-Born Orangutans ( Pongo abelii ) Engage in Triadic Interactions During Play

It has long been held that triadic interactions, or interactions between individuals that include shared perception and goals concerning an outside entity, require elaborate cognitive processes such as joint attention. With their connection to shared intentionality, triadic interactions have been a key topic of interest for developmental and evolutionary psychologists, notably when making comparisons between humans and other ape species. There is good evidence that chimpanzees and bonobos engage in triadic interactions; however, convincing evidence for orangutans are more limited and so far have been found only in the context of feeding. I engaged 11 wild-born sanctuary orangutans through the medium of a stick, allowing them to decide how to use the object and how to interact with me. The participating orangutans developed idiosyncratic ways of using the stick and engaging with me during the activity, and six of them alternated their gaze between the stick and me. When I interrupted the activity, the participating orangutans displayed more numerous and different behaviors than before the interruption to actively reengage me in the game. Much like human infants, they appeared more interested in the social interaction than in the stick. These findings confirm that triadic interactions occur in nonenculturated orangutans and are consistent with studies of other nonhuman great ape species, which also show triadic interactions, suggesting that joint attention and potentially shared intentionality may have an early origin in our evolutionary history

Kin-based cultural transmission of tool use in wild chimpanzees

Current research on animal culture has focused strongly on cataloging the diversity of socially transmitted behaviors and on the social learning mechanisms that sustain their spread. Comparably less is known about the persistence of cultural behavior following innovation in groups of wild animals. We present observational data and a field experiment designed to address this question in a wild chimpanzee community, capitalizing on a novel tool behavior, moss-sponging, which appeared naturally in the community in 2011. We found that, 3 years later, moss-sponging was still present in the individuals that acquired the behavior shortly after its emergence and that it had spread further, to other community members. Our field experiment suggests that this secondary radiation and consolidation of moss-sponging is the result of transmission through matrilines, in contrast to the previously documented association-based spread among the initial cohort. We conclude that the spread of cultural behavior in wild chimpanzees follows a sequential structure of initial proximity-based horizontal transmission followed by kin-based vertical transmission

Necessity creates opportunities for chimpanzee tool use

This work was funded by the European Research Council (FP7/2007–2013 / ERC grant number n° 283871) and the Swiss National Science Foundation (grant numbers 310030_143359 to K.Z.; CR13I1_162720, P300PA_164678 to T.G.).Although social transmission mechanisms of animal cultures are well studied, little is known about the origins of behavioral innovations, even in established tool users such as chimpanzees. Previous work has suggested that wild chimpanzees are especially prone to engaging with tools during extended periods of low food availability and after long travel, supporting the hypothesis that cultural innovation is facilitated by necessity revealing opportunities. Here, we tested this hypothesis with a field experiment that directly compared subjects' immediate variation in measures of current energy balance with their interest in a novel foraging problem, liquid honey enclosed in an apparatus accessible by tool use. We found that the previous distance traveled directly predicted subjects' manipulations of both the apparatus and the tool, whereas previous feeding time was negatively correlated to manipulation time. We conclude that "necessity" augments chimpanzees' likelihood of engaging with ecological "opportunities," suggesting that both factors are scaffolding foraging innovation in this and potentially other species.PostprintPostprintPeer reviewe

Variation in pedagogy affects overimitation in children and adolescents

S.D. was supported by The Société Académique Vaudoise and The Prepared Adult Initiative. A.F. was supported by a Leverhulme Early Career Research Fellowship (grant number ECF-2023-573). TG was supported by a grant from the Swiss National Science Foundation (PCEFP1_186832).Children are strong imitators, which sometimes leads to overimitation of causally unnecessary actions. Here, we tested whether learning from a peer decreases this tendency. First, sixty-five 7-10-year-old children performed the Hook task (i.e., retrieve a reward from a jar with tools) with child or adult demonstrators. The overimitation rate was lower after watching a peer than an adult. Second, we tested whether experiencing peer-to-peer learning versus adult-driven learning (i.e., Montessori versus traditional pedagogy) impacted overimitation. Sixty-six 4-18-year-old children performed the Hook task with adult demonstrators only. Montessori-schooled children had a lower propensity to overimitate. These findings emphasize the importance of the teaching model across the school years. While peer models favor selective imitation, adult models encourage overimitation.Peer reviewe