Monkey Business

Nathan Myhrvold gave me a very fun book, Superfreakonomics, and like all the books I read this week, it highlights Costa Rica by strange coincidence.

The book closes with the story of economics experiments (by Keith Chen from Stanford/Yale) introducing currency to capuchin monkeys such as this wild one (spotted today in the dry tropical forest canopy).

“Chen’s question was simply this: What would happen if I could teach a bunch of monkeys to use money?

For currency, Chen settled on a one-inch silver disc with a hole in the middle – kind of like Chinese money.

When the price of a given food rose, the monkeys bought less of it, and when the price fell, they bought more. The most basic law of economics held for monkeys as well as humans.

[They also] suffered from what psychologists call ‘loss aversion.’ They behaved as if the pain from losing a grape was greater than the pleasure from gaining one.

Day traders make the same kind of irrational decisions at a nearly identical rate. The data generated by the capuchin monkeys, Chen says, make them statistically indistinguishable from stock-market investors.

And then, the strangest thing happened in the lab.

One monkey, instead of handing his coin over to the humans for a grape, instead approached a second monkey and gave it to her. After a few seconds of grooming – bam! – the two capuchins were having sex. What Chen had seen…was the first instance of monkey prostitution in the recorded history of science. As soon as the sex was over, the capuchin who’d received the coin promptly brought it over to Chen to purchase some grapes.

Alas, Chen’s dream of capuchin capitalism never came to pass. The authorities who oversaw the monkey lab feared that introducing money to the capuchins would irreparably damage their social structure.

They were probably right.”