How Basic are Behavioral Biases? Evidence from Capuchin Monkey Trading Behavior

Behavioral economics has demonstrated systematic decision-making biases in both lab and field data. Do these biases extend across contexts, cultures, or even species? We investigate this question by introducing fiat currency and trade to a colony of capuchin monkeys, and recovering their preferences over a range of goods and gambles. We show that capuchins react rationally to both price and wealth shocks, but display several hallmark biases when faced with gambles, including reference-dependence and loss-aversion. Given our capuchins ’ inexperience with trade and gambles, these results suggest that loss-aversion extends beyond humans, and may be innate rather than learned. ∗We would like to acknowledge financial support from Whitebox Advisors and the Russell Sage Founda-tion, without which this research would not have been possible. Alisia Eckert provided invaluable research assistance throughout this project. Many people gave generously of their time on this and earlier drafts; w