Monkeys (Sapajus apella and Macaca tonkeana) and great apes (Gorilla gorilla, Pongo abelii, Pan paniscus, and Pan troglodytes) play for the highest bid.

Abstract

We thank E. Batôt and C. Dilger for their help with data collection. We are grateful to the animal carers of Leipzig Zoo, CIRMF, GFPA, and Edinburgh Zoo. Our thanks also go to J. Close and N. Poulin for their statistical advices, and to anonymous reviewers for their valuable comments on earlier version of the manuscript. This work was supported by grants from the Agence Nationale de la Recherche (ANR-08-412 BLAN-0042-01) and the European Science Foundation (Compcog Exchange Grant N°3648).

Variation in primate decision-making under uncertainty and the roots of human economic behaviour

“…In particular, primates are given a budget of allotted tokens they can distribute across experimenters with different exchange rates. Exchange paradigms involving either token or food trading have been used to test the four great apes [69,70], Tonkean macaques (Macaca tonkeana) [68,70], long-tailed macaques [68,69] and capuchins [68][69][70][71][72].…”

“…A final approach uses exchange tasks where animals learn to exchange tokens or food with a human. For example, animals may be initially provided with a food item, and then can exchange it for the opportunity to win a larger, equal or smaller food reward seen in one of several containers [68][69][70]. If the animal chooses to exchange, the content of one container is royalsocietypublishing.org/journal/rstb Phil.…”

Using natural ecology to predict higher cognition in human and non-human primates

“…This approach has been used across taxa, from corvids to hummingbirds to voles (Balda, & Kamil, 1989;Balda et al, 1995;Healy & Hurly, 2004;Okhovat, Berrio, Wallace, Ophir, & Phelps, 2015). Applying it to non-human primates, however, is less common but many such studies do exist (see Broihanne et al, 2019). Take a moment, however, to think about how it might apply to human cognition.…”

Non-human primates use combined rules when deciding under ambiguity

“…Lotteries were presented under four conditions (table 1): (a) risky: no cups were covered, thus all potential crackers were visible (figure 1a); (b) predictably advantageous: two of the six cups were covered, but the ranking of crackers by size enabled subjects to infer that two large crackers were hidden under the covers (see for example lottery 6, table 1); (c) predictably disadvantageous: two of the six cups were covered, and the individual could infer from their position that they contained small crackers (see for example lottery 22, table 1); and (d) ambiguous: two of the six cups were covered and subjects could not predict the size of the hidden crackers (figure 1b). Note that all subjects had already experienced the ordering of crackers by size in the lottery cups in a previous study on decision-making under risk [32].…”

“…This gradual decrease in the chances of winning probably facilitated the extraction of information about odds. Odds were modified from one trial to the next in a second version of this task [32], thus requiring individuals to pay close attention to the odds displayed to them at each trial. Here, many individuals applied a Maximax heuristic, and were more likely to gamble when there was at least one chance of winning (disregarding potential losses).…”