Vol. 11, No. 2, 2005 Page 7
Genes strongly influence an individual's sense of social responsibility, according to a recent study.
J. Philippe Rushton and colleagues compared 174 pairs of identical twins to 148 pairs of fraternal twins (who share only half as many genes), asking them if they agreed or disagreed with 22 statements such as "I am a person people can count on" and "Cheating on income tax is as bad as stealing." Responses to these questions are known to predict socially responsible behavior such as voting or volunteer activity.
Rushton reports that the answers of identical twins were nearly twice as similar as those of fraternal twins. Genes explained 42 percent of the individual differences in attitudes toward social responsibility, while shared home environment accounted for 23 percent and non-shared environment for the remainder. Genes had much more influence on the attitudes of males than on those of females.
The study also found that parents have little effect on children's social behavior once the children reach puberty. "That seems to be when their genes kick in," Rushton says, "and the influence of peers and other outside sources is much stronger in their social development."
"Genetic and environmental contributions to pro-social attitudes: a twin study of social responsibility," J. P. Rushton, Proceedings of the Royal Society of London: Biological Sciences, Vol. 271, No. 1557, Dec. 22, 2004, 2583-5. Address: J. Philippe Rushton, Department of Psychology, University of Western Ontario, London, Ontario N6A 5C2, Canada.
"Humans wired to be good," Jim Anderson, Western News, Univeristy of Western Ontario, January 20, 2005.