Money and Monkeys, or, What'll You Give for that Peanut?

Given the chance, monkeys handle cash in ways familiar to humans

• Hannah Schardt
• Mar 01, 2010

When it comes to shopping, capuchin monkeys—small natives of Central and South America—seem quite human. A new study from Yale University found that capuchins demonstrate the exact same rational and irrational behavior as humans when sent on shopping sprees.

Yale researchers taught capuchin monkeys to exchange shiny metal tokens for favorite foods, such as grapes or apple chunks. Once the monkeys grasped the concept they became, well, grasping—they even stole tokens from other monkeys.

In one experiment, the monkeys were given a budget of 10 tokens and allowed to exchange them for a variety of treats. Research assistants acted like shopkeepers, each assistant offering a different food for “sale.” As the monkeys “shopped,” researchers would change the value of the tokens. A token might be worth one grape one day but two grapes the next.

Keith Chen, the economist involved in the study, says the monkeys’ reaction to price fluctuation was perfectly rational—and quite human. When prices went up for one food, the monkeys bought less of it. When prices went down, they bought more. 

There are as yet no reports on whether the monkeys make use of credit cards or subprime loans.

Adapted from a National Wildlife magazine story, "Spend Like a Monkey," by Hannah Schardt, October/November 2005.