The genetics of political attitudes

The NYT reports:

As found in previous studies, attitudes about issues like school prayer, property taxes and the draft were among the most influenced by inheritance, the researchers found. Others like modern art and divorce were less so. And in the twins' overall score, derived from 28 questions, genes accounted for 53 percent of the differences.

This is a general rule of thumb: inheritance accounts for about 50% of personality and cognitive traits. I call it the Half-Full Glass (or the Half-Empty Glass, depending upon what I'm trying to emphasize).

But after correcting for the tendency of politically like-minded men and women to marry each other, the researchers also found that the twins' self-identification as Republican or Democrat was far more dependent on environmental factors like upbringing and life experience than was their social orientation, which the researchers call ideology. Inheritance accounted for 14 percent of the difference in party, the researchers found.

"We are measuring two separate things here, ideology and party affiliation," Dr. Hibbing, the senior author, said. He added that his research team found the large difference in heritability between the two "very hard to believe," but that it held up.

The implications of this difference may be far-reaching, the authors argue. For years, political scientists tried in vain to learn how family dynamics like closeness between parents and children or the importance of politics in a household influenced political ideology. But the study suggests that an inherited social orientation may overwhelm the more subtle effects of family dynamics.

A mismatch between an inherited social orientation and a given party may also explain why some people defect from a party. Many people who are genetically conservative may be brought up as Democrats, and some who are genetically more progressive may be raised as Republicans, the researchers say.

In tracking attitudes over the years, geneticists have found that social attitudes tend to stabilize in the late teens and early 20's, when young people begin to fend for themselves.

Some "mismatched" people remain loyal to their family's political party. But circumstances can override inherited bent. The draft may look like a good idea until your number is up. The death penalty may seem barbaric until a loved one is murdered.

Family formation is a big influence. The researchers need to look at the big regional differences in voting, between Bush getting only 40% of the white vote in Massachusetts and 85% of the white vote in Mississippi. That's not just genetics.

Has anyone done longitudinal studies to see how voting changes as people move?

The researchers are not optimistic about the future of bipartisan cooperation or national unity. Because men and women tend to seek mates with a similar ideology, they say, the two gene pools are becoming, if anything, more concentrated, not less.

Razib has more at www.GNXP.com .

My published articles are archived at iSteve.com -- Steve Sailer