hormones inspire feelings of love and generosity

  Many times, two siblings raised by the same parents, and subject to similar environmental influences, can turn out to be polar opposites: one kind and generous, the other mean-spirited. A new study reveals that the latter might simply have been dealt the wrong hormone receptor genes.

Oxytocin and vasopressin, two hormones that inspire feelings of love and generosity when they flood our brains, bind to neurons by attaching to molecules called receptors, which can come in different forms. The new research, led by psychologist Michel Poulin of the University of Buffalo, suggests that if you have the genes that give you certain versions of those hormone receptors, you're more likely to be a nice person than if you have the genes for one of the other versions. However, the researchers found that the genes work in concert with a person's upbringing and life experiences to determine how sociable — or anti-social — he or she becomes.

As detailed in a new article in the journal Psychological Science, hundreds of people were surveyed about their attitudes toward civic duty, their charitable activities and their worldview. They were asked, for example, whether people have an obligation to report crimes, sit on juries or pay taxes, whether they themselves engage in charitable activities such as giving blood or volunteering, and whether people — and the world as a whole — are basically good, or are threatening and dangerous. Of those surveyed, 711 people provided a sample of their saliva for DNA analysis, which showed which version of the oxytocin and vasopressin receptors they had.

Study participants who saw the world as a threatening place, and the people in it as inherently bad, were nonetheless nice, dutiful and charitable as long as they had the versions of the receptor genes associated with niceness. These "nicer" versions of the genes, Poulin said, "allow you to overcome feelings of the world being threatening and help other people in spite of those fears."