Washington, Oct 13 - If you go out of your way to help strangers in distress, it could be because of your upbringing rather than your genes, says a new study.

University of California-Davis (UC-D) researchers led by Adrian V. Bell used a mathematical equation, called the Price equation, that describe the conditions for altruism to evolve.

This equation motivated them to compare the genetic and the cultural differentiation among neighbouring social groups.

Using previously calculated estimates of genetic differences, they used the World Values Survey (WVS) as a source of data to compute the cultural differentiation between the same groups.

The researchers found that the role of culture had a much greater scope for explaining

our pro-social behaviour than genetics.

But ancient cultural practices, such as exclusion from the marriage market, denial of the fruits of cooperative activities, banishment and execution happen now as they did then, said an UC-D release.

Bell is currently continuing his research in Tonga. He is developing a survey instrument

that will help capture people's cultural beliefs and measure the effect of migration on the similarities and differences between populations.

These findings were presented in the Monday edition of Proceedings of the National Academy of Sciences.