A research by psychologists at University of Buffalo and University of California, has affirmed that at least part of the reason some people are kind and generous lies in their genes.

The study, published this month in Psychological Science journal, looked at the behavior of the study subjects who had special versions of receptors of two hormones that, in laboratory and closely-related research, were associated with niceness. Previous laboratory studies have linked the hormones oxytocin and vasopressin to the way we treat each other.

Oxytocin, so called “Love Hormone”, is excreted in pregnant women during delivery, and is considered one of the important compounds that bind mother with her infant; its rates rise when we hug someone we love and several studies explained its effect on the improvement of relations between spouses.

However, Vasopressin is a hormone that contributes to the social behavior, and in the lab, subjects exposed to this hormone demonstrate greater sociability.   
The led author says: “this study was an attempt to apply previous findings to social behaviors on a larger scale; to learn if these chemicals provoke in us other forms of pro-social behavior: urge to give to charity, for instance, or to more readily participate in such civic endeavors as paying taxes, reporting crime, giving blood.”

Subjects were surveyed as to their attitudes toward civic duty, other people and the world in general, and about their charitable activities. Study subjects took part in an Internet survey with questions about civic duty, such as whether people have a duty to report a crime or pay taxes; how they feel about the world, such as whether people are basically good or whether the world is more good than bad; and about their own charitable activities, like giving blood, working for charity.

Of those surveyed, 711 subjects provided a sample of saliva for DNA analysis, which showed what form they had of the oxytocin and vasopressin receptors.

The study found that “study participants who found the world threatening were less likely to help others -- unless they had versions of the receptor genes that are generally associated with niceness". These "nicer" versions of the genes, “allow you to overcome feelings of the world being threatening and help other people in spite of those fears”, but further studies is needed "because most connections between DNA and social behavior are complex."

"We aren't saying we've found the niceness gene,” the led author concluded "But we have found a gene that makes a contribution. What I find so interesting is the fact that it only makes a contribution in the presence of certain feelings people have about the world around them."