Washington, Feb 19 : Natural selection can act on human culture as well as on genes, says a new study which shows that cultural traits affecting survival and reproduction evolve at a different rate than other cultural attributes.
The study, conducted by researchers at Stanford University, states that speeded or slowed rates of evolution typically indicate the action of natural selection in analyses of the human genome.
In the study of cultural evolution, the research team compared the rates of change for structural and decorative Polynesian canoe-design traits.
"Biological evolution of inherited traits is the essential organizing principle of biology, but does evolution play a corresponding role in human culture"" said Jared Diamond, a professor of geography at the University of California-Los Angeles and author of Guns, Germs and Steel.
"This paper makes a decisive advance in this controversial field," Diamond added.
The study reviewed canoe designs from 11 Oceanic island cultures. The researchers evaluated 96 functional features (such as how the hull was constructed or the way outriggers were attached) that could contribute to the seaworthiness of the canoes and thus have a bearing on fishing success or survival during migration or warfare.
They also evaluated 38 decorative or symbolic features (such as the typeae design traits from island group to island group).
The statistical test results clearly revealed that the functional canoe design elements changed more slowly over time, indicating that natural selection could be weeding out inferior new designs.
This cultural analysis is similar to analyses of the human genome that have been successful in finding which genes are under selection.
Nina Jablonski, chair of the Anthropology Department at Pennsylvania State University, said: "This paper is revolutionary in its approach ... one of the most significant papers to be written in anthropology in the last 20 years."
Authors of the study said their results speak directly to urgent social and environmental problems.
"People studying climate change, population growth, poverty, racism and the threat of plagues all know what the problems are and what we should be doing to solve them," said Paul Ehrlich, the Bing Professor of Population Studies at Stanford.
The study is published in online Proceedings of the National Academy of Sciences.