The Moral Molecule

By Medical Discovery News

Aug. 4, 2012

Will politicians on Capital Hill ever be able to work together again? Though that may seem to call for a miracle, a mere hormone might do the trick. A recent study suggests a tiny hormone, oxytocin, causes feelings of trust and generosity in humans and other mammals.

Oxytocin is primarily known for its role in childbirth and breastfeeding. As a woman goes into labor, the hormone induces uterine contractions to speed up delivery. It then stimulates the body to release breast milk when an infant begins nursing.

Beyond these physiological functions, increased levels of oxytocin enhance bonding between a mother and her child. It also plays a role in pair bonding, sexual behavior, and even the ability to form normal social attachments.

Recent studies by Paul D. Zak, chair of economics at Claremont Graduate University in California, present oxytocin as an even more intriguing hormone. He calls it the “moral molecule,” and said it explains why some people give freely while others are stingy.

In a series of double blind experiments, Zak and his colleagues compared trusting behavior between a group of people who were administered oxytocin intranasally against a control group given a placebo. The two groups were each asked to play a trust game with money. Each person was given $12. The “investor” has the option to give any amount of their money to a “trustee.” Any amount given to the trustee was immediately tripled. So, a trustee could end up with a maximum of $48. The trustee could then choose to transfer back to the investor any or all of that money.

The results revealed that 45 percent of those who received the oxytocin displayed maximal trust by giving the trustee all $12 while only 21 percent of the control subjects did so. People in the oxytocin group who did not give the full amount still consistently gave away more of their money than the control group. These results suggest oxytocin affects behavior associated with trust, along with its other roles in social attachments and affiliation.

What’s striking about Zak’s experiment is that when he did the studies without administering oxytocin, the trustees who were generously given money, gave generously back. And blood samples showed their oxytocin levels shot up simply because they felt trusted, and in return displayed trust. In other words, oxytocin levels can surge from something as simple as a massage, prayer, singing, and other activities that foster social connections.

But this one hormone does not work in isolation. Human behavior is influenced by other hormones and past experiences. For example, in certain situations, a surge of testosterone would compete with the effects of oxytocin.

Going on the theory that oxytocin is central to a person’s ability to socially connect, scientists have already begun testing its effect on people with autism. Initial results are positive, paving the way for research on oxytocin’s effects on other social dysfunction disorders such as depression and schizophrenia.

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