Have you ever wondered how people choose their politics? Or did you just assume that they came from their parents? It turns out that it is a little bit of both. Here is what science tells us about whether Republicans and Democrats are made or born.


Epidemiology and politics: more than meets the eye

Nick Martin, an Australian geneticist, studies the epidemiology of disease transmission in twins. Why twins, you might ask? Because twins, fraternal and identical, can point to genetic influences in biology and medicine. For instance, if type I diabetes occurs more frequently in identical twins than in fraternal ones, and the incidence in both is higher than in the general population, then the obvious conclusion is that genetics has a strong influence in this disease.

Obviously, what Martin is interested in is the genetic contribution to disease transmission. But it occurred to him that one can use the twin study approach to study transmission of social attitudes. For this purpose, he studied 4,500 pairs of fraternal and identical twins.

And the result? Genetic factors, rather than cultural ones, were mostly responsible for family resemblance in social attitudes. Amazing! These results should have shaken up a lot of sociologists, psychologists, and cultural anthropologists. But the bombshell was a dud. When the paper was published in the prestigious Proceedings of the National Academy of Sciences (vol.83, pp. 4364-4368, 1986), it was met with a deafening silence.


Enter the political scientists

Fast forward to 2005. Alford and Hibbing reanalyzed the data in Martin’s paper (American Political Science Review, vol. 99, 153-167, 2005), but with an emphasis on political orientation. They constructed an index of conservatism or liberalism, based on responses to questions on attitudes toward abortion, gun control, the death penalty, apartheid, and so forth.

What they found was that

40-50% of the variation in political orientation was genetic, and almost none resulted from parental socialization.

But there is an unexpected twist at the end this story. When they analyzed actual political affiliation, the results were the reverse—genetics had almost no influence, while shared environment was the key.


What are the implications?

This observation has profound implications for our political and social life.

  • Does that mean the “genetically liberal” whites migrating from the Northeast to the South, will start voting Republican?
  • And vice versa: Will a large influx of “genetically liberals” to the Republican South change the environment so as to induce “genetically conservatives” to switch their voting preferences?
  • Is this the answer to Thomas Frank’s anguished question in his book “What’s Wrong with Kansas? How Conservatives Won the Heart of America?
  • Or is it the answer to the broader question that political scientists and politicians grappled with for generations: Why do people vote against their own interests?

Rich white New Yorkers or rich and famous Hollywood stars should vote Republican in order to maximize their wealth. But by and large, they vote Democratic. The farmers of Kansas would have been much better off with large government subsidies, a robust safety net, public works projects like highways and irrigation projects—yet, they vote mainly Republican.

Economists should take note as well. Their economic models are predicated on the theory that people make “rational choices”. Not quite; apparently, genetics has more to do with their decision making rather than rational analysis does. We’ll examine the neurobiological basis of economic decision-making in a future posting.

Last but not least. Psychologists tell us that when we do or say things that are inconsistent with our core beliefs or knowledge, we experience an emotional discomfort. They coined the term “cognitive dissonance” for this unhappy state of affairs. The political corollary: The more extreme a liberal party becomes, the greater the cognitive dissonance of its “genetically conservative” members and the greater the likelihood that they will eventually resolve their discomfort and change their vote. To wit: the Reagan Democrats.

And vice versa: The more extreme the Republican party becomes, the greater defections they will suffer. To wit: the latest election results.


Take home lesson:

Things are not as simple as they seem; nothing is linear or straightforward. We are complex animals, sometimes frustratingly so, and that’s what makes us so fascinating.

Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.


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