Washington, April 11 (IANS) Part of the reason why some people are kind and generous may have more to do with their genes than their mother's precepts, says a new psychology study.

The study, co-authored by Anneke Buffone of University at Buffalo and E. Alison Holman, University of California, Irvine, looked at the behaviour of subjects who have versions of receptor genes for two hormones that, in lab and close relationship research, are linked with being nice.

Previous lab studies have linked the hormones oxytocin and vasopressin to the way we treat one another, says Michel Poulin, assistant professor of psychology at Buffalo, who led the study, the journal Psychological Science reports.

In fact, they are known to make us nicer people, at least in close relationships. Oxytocin promotes maternal behaviour, for example, and in the lab, subjects exposed to the hormone demonstrate greater sociability, according to a Buffalo statement.

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.

"Specifically, 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," Poulin says..

These "nicer" versions of the genes, says Poulin, "allow you to overcome feelings of the world being threatening and help other people in spite of those fears.

"So if one of your neighbours seems really generous, caring, civic-minded kind of person, while another seems more selfish, tight-fisted and not as interested in pitching in, their DNA may help explain why one of them is nicer than the other," Poulin concludes.