Have you ever seen a dog trade a toy for food? Neither have I, and that’s because Adam Smith, the founder of classical economics stated that monetary exchange belongs to human beings alone, meaning, Humans are the only species that will trade money for something else. But in a Yale-New Haven Hospital laboratory, Capuchin monkeys were taught to use money, and to their surprise, the monkeys began to trade money for sex.

The capuchin monkey is a brown monkey about the size of a human baby. These monkeys always have two things on their minds, Food and Sex. Keith Chen, a Yale economist, and Laurie Santos, a psychologist exploited the monkey’s natural desires to figure out what would happen when they introduced a currency into their society. To be honest, the researchers were NOT teaching the monkey’s how to trade money for sex. They simply taught the monkeys how to trade coins for grapes or Jell-O.

The idea was to give a monkey a dollar and see what it did with it. The currency Chen settled on was a silver disc, one inch in diameter, with a hole in the middle — ”kind of like Chinese money,” he says. It took several months of rudimentary repetition to teach the monkeys that these tokens were valuable as a means of exchange for a treat and would be similarly valuable the next day. Having gained that understanding, a capuchin would then be presented with 12 tokens on a tray and have to decide how many to surrender for, say, Jell-O cubes versus grapes. This first step allowed each capuchin to reveal its preferences and to grasp the concept of budgeting.

But then strange things started to happen, when the monkeys were presented with the 12 tokens, the monkey would grab the coins and toss them to the neighboring cell where all the monkeys would grab as many coins as they could. This meant that monkeys knew they could steal the coins and then hold the coins as ransom in effect creating a bank heist. Which is a interesting, but not as interesting as what happened next.

When the monkeys from the opposing cell – where the coins were thrown to – collected the money, not all of the monkeys were lucky enough to get coins. Some monkeys got the money with the intention of buying grapes, other monkeys got the money with a completely different intention. The monkeys that didn’t get any coins started to look for ways of getting those coins, they found that they could trade sex for coins. The monkey who was paid for sex immediately traded the token in for a grape.

This proved to be the turning point for the experiment since the researchers felt the experiment was going “south” to quickly. The capuchin lab at Yale has been built and maintained to make the monkeys as comfortable as possible, and especially to allow them to carry on in a natural state. The introduction of money was tricky enough; it wouldn’t reflect well on anyone involved if the money turned the lab into a brothel. To this end, Chen has taken steps to ensure that future monkey sex at Yale occurs as nature intended it and not for who could pay out the most money.

But these facts remain: When taught to use money, a group of capuchin monkeys stole when they could; used money for food and, on occasion, sex. Via: NY Times