Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More Efficient Tool-Use Technique

Abstract

BackgroundThe evidence for culture in non-human animals has been growing incrementally over the past two decades. However, the ability for cumulative cultural evolution, with successive generations building on earlier achievements, in non-human animals remains debated. Faithful social learning of incremental improvements in technique is considered to be a defining feature of human culture, differentiating human from non-human cultures. This study presents the first experimental evidence for chimpanzees' social transmission of a more efficient tool-use technique invented by a conspecific group member.Methodology/Principal FindingsThe chimpanzees were provided with a straw-tube, and spontaneously demonstrated two different techniques in obtaining juice through a small hole: “dipping” and “straw-sucking”. Both the “dipping” and “straw-sucking” techniques depended on the use of the same tool (straw-tube) for the same target (juice) accessible from exactly the same location (small hole 1 cm in diameter). Therefore the difference between “dipping” and “straw-sucking” was only in “technique”. Although the two techniques differed significantly in their efficiency, their cognitive and perceptuo-motor complexity were comparable. All five chimpanzees who initially performed the “dipping” technique switched to using the more efficient “straw-sucking” technique upon observing a conspecific or human demonstrate the more proficient alternate “straw-sucking” technique.Conclusions/SignificanceThe social learning mechanism involved here was clearly not local or stimulus enhancement, but imitation or emulation of a tool-use technique. When there is no biologically relevant difference in cognitive or perceptuo-motor complexity between two techniques, and when chimpanzees are dissatisfied with their own technique, chimpanzees may socially learn an improved technique upon close observation of a proficient demonstrator. This study provides important insights into the cognitive basis for cumulative culture in chimpanzees, and also suggests possible conditions in which cumulative cultural evolution could arise even in non-human animals.

Cultural Evolution: A Review of Theory, Findings and Controversies

“…These studies with phylogenetically diverse species show that adaptive social learning rules likely evolved independently in response to particular ecological conditions rather than exclusively in our own species' recent ancestors. Indeed, chimpanzees are surprisingly reluctant to switch to higher-payoff behaviours (Marshall-Pescini and Whiten 2008; although see Yamamoto et al 2013) and while they do exhibit social learning, and this is sometimes labelled 'conformity' (e.g. Whiten et al 2005), conformity has not been demonstrated in chimpanzees in the specific sense of being disproportionately more likely to copy the majority (van Leeuwen and Haun 2013).…”

The Psychology of Cows

“…Many animals engage in social learning (see Galef & Laland, 2005), including chimpanzees (e.g., Bering, Bjorklund, & Ragan, 2000;Whiten, 1998;Yamamoto, Humley, & Tanaka, 2013), orangutans (Pongo pygmaeus; Bering et al, 2000), capuchin monkeys (Cebus apella; Ottoni & Mannu, 2001), and other social mammals, as well as birds, such as ravens (Bugnyar & Kotrschal, 2002), quail (Köksal & Domjan, 1998), and chickens (Nicol, 2006), and fish (e.g., nine-spined sticklebacks, Pungitius pungitius; Kendal, Rendell, Pike, & Laland, 2009), and reptiles (bearded dragon, Pogona vitticeps; Kis, Huber, & Wilkinson, 2015).…”

Acquisition of a socially learned tool use sequence in chimpanzees: Implications for cumulative culture

“…Thus, we see a modification, in terms of complexity and efficiency, of an existing cultural behavior. However, investigation with captive chimpanzees concluded that cumulative learning of increasingly complex skills may be absent in chimpanzees (Dean et al, 2012; Marshall-Pescini & Whiten, 2008) or limited to small modifications in behavioral efficiency that may easily be invented by a few adept individuals (Yamamoto, Humle, & Tanaka, 2013). In Dean et al (2012) groups of capuchins, chimpanzees, and nursery school children were presented with a puzzle box containing three, increasingly difficult, task solutions.…”