The Evolution of Our Preferences: Evidence from Capuchin-Monkey Trading Behavior
The Endowment Effect in Capuchin Monkeys
Joint with Venkat Lakshminarayanan & Laurie Santos
Philosophical Transactions of the Royal Society: Biological Sciences, December 2008
In humans, the capacity for economically rational choice is constrained by a variety of preference biases: humans evaluate gambles relative to arbitrary reference points; weigh losses heavier than equally sized gains; and demand a higher price for owned goods than for equally preferred goods that are not yet owned. To date, however, fewer studies have examined the origins of these biases. Here, we review previous work demonstrating that human economic biases such as loss aversion and reference dependence are shared with an ancestrally related New World primate, the capuchin monkey (Cebus apella). We then examine whether capuchins display an endowment effect in a token trading task. We identified pairs of treats (fruit discs versus cereal chunks) that were equally preferred by each monkey. When given a chance to trade away their owned fruit discs to obtain the equally valued cereal chunks (or vice versa), however, monkeys required a far greater compensation than the equally preferred treat. We show that these effects are not due to transaction costs or timing issues. These data suggest that biased preferences rely on cognitive systems that are more evolutionarily ancient than previously thought—and that common evolutionary ancestry shared by humans and capuchins may account for the occurrence of the endowment effect in both species.
Behavioral economics has demonstrated systematic decision-making biases in bothlab and ﬁeld data. But are these biases learned or innate? We investigate this questionusing experiments on a novel set of subjects — capuchin monkeys. By introducing a ﬁatcurrency and trade to a capuchin colony, we are able to recover their preferences over awide range of goods and risky choices. We show that standard price theory does a remarkably good job of describing capuchin purchasing behavior; capuchin monkeys reactrationally to both price and wealth shocks. However, when capuchins are faced withmore complex choices including risky gambles, they display many of the hallmark biases of human behavior, including reference-dependent choices and loss-aversion. Giventhat capuchins demonstrate little to no social learning and lack experience with abstract gambles, these results suggest that certain biases such as loss-aversion are aninnate function of how our brains code experiences, rather than learned behavior or theresult of misapplied heuristics.
It is amazing how the thought process of Cebus apella can be so relative to Homo sapiens, but does that make our (H. sapiens) thought process learned or innate as well? Everyone wants more for less, but I guess that only confirms the cognition of the author and researchers. I guess we’ll rule it a law of nature. MORE FOR LESS! Capuchin monkeys tend to be so ingenuitive and crafty. I think this is what makes them so compatible amongst the population each monkey be a part off. God truly graced the earth with these animals. Hopefully I can do similar research in grad-school.