Spread of arbitrary conventions among chimpanzees: a controlled experiment

Abstract

Wild chimpanzees (Pan troglodytes) have a rich cultural repertoire-traditions common in some communities are not present in others. The majority of reports describe functional, material traditions, such as tool use. Arbitrary conventions have received far less attention. In the same way that observations of material culture in wild apes led to experiments to confirm social transmission and identify underlying learning mechanisms, experiments investigating how arbitrary habits or conventions arise and spread within a group are also required. The few relevant experimental studies reported thus far have relied on cross-species (i.e. human-ape) interaction offering limited ecological validity, and no study has successfully generated a tradition not involving tool use in an established group. We seeded one of two rewarded alternative endpoints to a complex sequence of behaviour in each of two chimpanzee groups. Each sequence spread in the group in which it was seeded, with many individuals unambiguously adopting the sequence demonstrated by a group member. In one group, the alternative sequence was discovered by a low ranking female, but was not learned by others. Since the action-sequences lacked meaning before the experiment and had no logical connection with reward, chimpanzees must have extracted both the form and benefits of these sequences through observation of others.

Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus)

“…In a recent study on translocation events of zoo chimpanzees (which mimics the immigration events in the wild), it was found that the immigrating individuals conform to vocalization pattern of their new group [81]. Studies in captivity have shown that adjustments based on the desire to create or maintain a positive group sense might exist in chimpanzees [64,65,82,83]. Adjusting behaviour potentially could reduce differences between the local group member and the immigrant and favour acceptance into the group.…”

Conformity without majority? The case for demarcating social from majority influences

“…Starting with one skilled individual (natural invention or trained skill), the rest of the group acquires the same particular way of behaving by means of social learning (Hopper et al, 2011;Perry, 2009;Whiten et al, 2005). On the other hand, the label 'conformity' has been used to describe the process by which primates would revert back to the majority strategy after discovering an alternative strategy (chimpanzees: Bonnie et al, 2007;Hopper et al, 2011;Whiten et al, 2005;capuchin monkeys: Dindo et al, 2008capuchin monkeys: Dindo et al, , 2009). Here, after socially acquiring a particular way of behaving, some individuals would occasionally explore an alternative strategy, but then change back to preferring the majority strategy.…”

“…In recent years, majority influence has become a favourable research topic for behavioural biologists. One line of research has focused on our closest living relatives, the nonhuman primates (chimpanzees, Pan troglodytes: Bonnie, Horner, Whiten, & de Waal, 2007;Haun, Rekers, & Tomasello, 2012;Hopper, Schapiro, Lambeth, & Brosnan, 2011;Whiten, Horner, & de Waal, 2005; capuchin monkeys, Cebus apella: Dindo, Thierry, & Whiten, 2008;Dindo, Whiten, & de Waal, 2009;Perry, 2009), which could enable intriguing analysis of the evolutionary roots of this human phenomenon (MacLean et al, 2012). Another line of research has aimed to investigate the possibility of convergent evolution of conformity by focusing on phylogenetically more distant species, such as fish (Day, MacDonald, Brown, Laland, & Reader, 2001;Kendal, Coolen, & Laland, 2004;Pike & Laland, 2010), rats (Galef & Whiskin, 2008;Jolles, de Visser, & van den Bos, 2011;Konopasky & Telegdy, 1977) and fruit flies (Battesti, Moreno, Joly, & Mery, 2012).…”

Evolutionary precursors of social norms in chimpanzees: a new approach

“…They are characterized 225 by a functional and goal-directed task and constitute efficient means to achieve physical ends; 226 for example, termites must be extracted from their mound to be eaten. Thus, chimpanzees 227 most certainly do not use specific tools because everybody else does so, although this might 228 be the case for an individual's first use of a tool, but because after some experience they 229 understand the utility and effectiveness of the practice (Bonnie et al 2007;Turiel 1983). 230…”