|Prairie voles with their litter|
Oxytocin also attracted the attention of researchers of a totally unrelated field: economics. Some unconventional economists decided to put to the test the basic belief of capitalism that market decisions are rational. They found that they are not. Human transactions are based more on trust and empathy that on cold-blooded decisions on what is to lose and what is to gain. For example, people in all cultures engage in something called altruistic punishment: they will go at great length to punish individuals that they perceive as being unfair and untrustworthy. One way they determined this is with an experiment called the “ultimatum game”. In it there are two players. Player one is given a sum of money, say $10, of which he has to offer a certain amount to player 2. If player 2 takes the offer, both get to keep the agreed amount of money. However, if player 2 rejects to offer, both of them lose the money. The results of the ultimatum game are consistent between people of all sexes, religions and cultures: below a certain amount (about $3-4 if the total amount is $10), player 2 decides that player 1 is not treating him fairly and rejects the offer. That means that he is willing to lose 2, 3 or even 4 bucks to punish player 1 for being greedy, that’s why is called “altruistic punishment”. Oxytocin comes into play because when their levels of oxytocin were increased players were more generous in their monetary offers. Testosterone did the opposite. In fact, men are more inclined to altruistic punishment than women.
Oxytocin and vasopressin are now called the “social hormones” because they strongly influence social behaviors like bonding, trust and empathy. However, we should not fall into the simplistic belief that oxytocin makes us good. It has been observed that this neuropeptide is involved in some nasty human behaviors, like xenophobia and intolerance. This is because oxytocin increases both bonding with the members of our group and exclusion of anybody perceived as a stranger. If you think about it, monogamy entails both feeling close to our spouse and rejecting member of the opposite sex that are not our spouse: bonding and exclusion. On the other hand, the role of vasopressin in monogamy in males seems to have more to do with possessiveness and territoriality than with emotional bonding - the male perceives the female as part of his territory and defends her as such. Likewise, altruistic punishment has a good side -like pursuing criminals-, and a bad side -like road rage and other conflicts that get started when we think that somebody is taking advantage of us.