The Root of All Monkey Evil

The first installment of Freakonomists Stephen Dubner and Steven Levitt's new New York Times column is almost as intriguing as it is hilarious.

It details Yale behavioral economist Keith Chen's recent work with capuchin monkeys, namely teaching them to use currency.  Impressively, the monkeys seemed to develop an appreciation for stored value, budgeting, even relative valuation and utility maximization.

The monkey marketplace offered wholesome monkey staples like grapes, jello, and cucumbers.  The inevitable monkey black marketplace, however, wrought various societal ills on the fledgling monkey economy, including theft, gambling, and prostitution.  (And the occasional poo-fling).

Once, a capuchin in the testing chamber picked up an entire tray of tokens, flung them into the main chamber and then scurried in after them -- a combination jailbreak and bank heist ...

Something else happened during that chaotic scene, something that convinced Chen of the monkeys' true grasp of money. Perhaps the most distinguishing characteristic of money, after all, is its fungibility, the fact that it can be used to buy not just food but anything. During the chaos in the monkey cage, Chen saw something out of the corner of his eye that he would later try to play down but in his heart of hearts he knew to be true. What he witnessed was probably the first observed exchange of money for sex in the history of monkeykind. (Further proof that the monkeys truly understood money: the monkey who was paid for sex immediately traded the token in for a grape.)