The outpouring of generosity and compassion to tsunami survivors (search) could trace back to the givers’ genes. Humans seem to be wired to help each other, new research shows.

Researcher J. Philippe Rushton works in the University of Western Ontario’s psychology department. He’s fascinated by the possible connection between genes and behavior. Recently, he studied how genetics affect social responsibility, which includes positive actions, such as volunteering, voting and filling out tax forms honestly.

Rushton compared social responsibility among twins. He mailed surveys to hundreds of twins listed on the University of London’s twin registry. Responses came back from 174 sets of identical twins and 148 pairs of fraternal twins. Identical twins (search) come from the same egg and have the same genes; fraternal twins (search) come from two different eggs and are not genetically identical.

The survey included 22 statements including, “I am a person people can count on,” and “Cheating on income tax is as bad as stealing.” Using a scale of 1-5, the twins rated how much they agreed with each statement. Answers to the social responsibility questionnaire has been shown to predict real-life behavior such as people’s level of social responsibility

The questionnaires were sent out in 1982, with a follow-up in 1983. Rushton reported the findings in the Dec. 22, 2004 issue of Proceedings of the Royal Society: Biological Sciences.

Is Goodness in the Genes?

Genes were a bigger influence than upbringing or personal experience, says Rushton. Genetics accounted for 42 percent of the difference in responses between the two different types of twins, while upbringing only explained 23 percent of the variation, says Rushton. The remaining gap stemmed from the twins’ personal experiences, he adds.

Men and women had slightly different results. Genes appeared to have a stronger influence on men, while upbringing was more important for women. “The genetic contribution was lower for women than men (40 percent vs. 50 percent) and the common upbringing environment higher (40 percent vs. 0 percent),” says Rushton.

That could mean that parents treat sons and daughters differently. “Parents may monitor female behavior more carefully than they do male behavior,” says Rushton.

Several other trends stood out. Women had higher scores than men, and older people had higher scores than younger people.

The results indicate “people are innately good,” says Rushton, in a news release. He’s gathered similar findings in his past studies of genetics and altruism, empathy, and aggression.

Whether people are born good is a question that’s as old as time. Rushton notes that genes and positive social behavior have only been studied four other times, with wildly varying results. Those earlier studies gave genetics credit for anywhere from 0-72 percent of good social behavior.

Rushton calls for more studies on the topic. Meanwhile, he says there’s enough evidence for evolutionary psychologists to start working on the origins of goodness.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Rushton, J. Proceedings of the Royal Society: Biological Sciences, Dec. 22, 2004; vol 271: pp 2583-2585. News release, University of Western Ontario.