Where do we get our political beliefs? Are they drilled into us by our parents? Did we "borrow" them from friends and colleagues?
There's no doubt that environmental factors influence our beliefs and behavior. But a provocative new study shows another big contributor to our political views.
We're talking genes.
"We've tended to think of political attitudes and behaviors as being rooted in the environment," Dr. Kevin Smith, a political scientist at the University of Nebraska-Lincoln and co-author of the new study, says in the video (above). "What our study shows along with a number of other studies is that they seem to be at least partially rooted in our biology."
For the study, Smith and his colleagues surveyed 682 pairs of middle-aged twins, all recruited from a large database called the Minnesota Twin Registry. Half of the twins were identical (monozygotic), sharing all of the same genes. Half were fraternal, sharing only about 50 percent of their genes.
The survey included questions about the twins' attitudes toward a range of political issues, from gay marriage to school prayer to the best way to structure society.
What did the researchers find? The identical twins' political views were consistently more similar than were those of the fraternal twins, and further statistical analysis revealed that these differences were partially the result of genetic influences.
"I know people get bent out of shape about this," Smith said in a written statement. "The environment is important, it's just not everything. You can talk about biology and you can talk about the environment. Who we are is a combination of both."
The research builds upon a 2005 study that found similar evidence for a genetic influence on political ideology, but was limited to analyzing existing survey data that contained only a few questions related to politics.
The new study comes at a time of intense political polarization, especially in the federal government, and the researchers believe it may offer insights and a possible way to ease tensions.
"Some observers have the idea that if people just talk about politics long enough, everybody will come to agreement," Dr. John Hibbing, a political scientist at the university and co-author of the new study, told HuffPost Science in an email. "Our research, as well as that of others in the field, indicates that political differences run deep, are biological, and affect the way the world is perceived and processed."
For instance, a 2012 study from the university found that conservatives tend to pay more attention and react more strongly to negative images, compared to liberals.
Recognizing the biological basis of "political orientation" might make people more tolerant of one another and thus encourage compromise, Dr. Hibbing added. "It is pleasant to believe our political foes are merely uninformed but often times (not always) they are well-informed but just have different predispositions."
The new study was published in the December 2013 issue of Political Psychology.