Can Your Genes Predict Whether You'll Be a Conservative or a Liberal?

Scientific research shows political partisanship transcends economics, environment, and upbringing.
Republicans from the cradle to the grave? (Brian Snyder/Reuters)

Among the first scientists to dig for the roots of political orientation were a couple of pioneering psychologists in California named Jack and Jeanne Block. Back in 1969, the Blocks asked two challenging questions: How deep do our political leanings run? And how early in life do these leanings begin to form within each of us?

In search of answers, they devised a very unusual study, and they began it with kids who were still in nursery school. On the face of it, the premise of the study seemed absurd: What did nursery school kids know about Democrats or Republicans, or about the complicated, hot-button issues of the day? Still, the Blocks were serious researchers from the University of California at Berkeley, and they were determined to break new ground.

For their experiment, the two professors placed a group of 128 nursery-school children under the close observation of several teachers for a period of seven months. Then the Blocks had each of these caretakers measure the three-year-olds’ personalities and social interactions, using a single standardized test. The same children then underwent this process again at age four, with a different set of teachers at a second nursery school. The Blocks tabulated the scores for each child and then locked the numbers away in a vault.

The test scores then sat in the vault for the next two decades, while the children from the study went their separate ways in life. They grew up, completed their educations, and turned into young adults. After 20 years had passed, the Blocks succeeded in tracking down 95 of their original 128 subjects, in the hope of measuring how liberal or conservative each of them had become. This time they asked the young adults, now age 24, to situate themselves on a five-point political spectrum. They also asked them to express their opinions on a number of highly partisan, hot-button issues. In particular, several of these questions measured their tolerance of inequality between the genders and between different racial groups. In addition, they were asked to describe any political activism they might have participated in during the intervening years.

The results, published in 2006 by the Journal of Research in Personality, were astonishing. In analyzing their data, the Blocks found a clear set of childhood personality traits that accurately predicted conservatism in adulthood. For instance, at the ages of three and four, the “conservative” preschoolers had been described as “uncomfortable with uncertainty,” as “rigidifying when experiencing duress,” and as “relatively over-controlled.” The girls were “quiet, neat, compliant, fearful and tearful, [and hoped] for help from the adults around.”

Likewise, the Blocks pinpointed another set of childhood traits that were associated with people who became liberals in their mid-twenties. The “liberal” children were more “autonomous, expressive, energetic, and relatively under-controlled.” Liberal girls had higher levels of “self-assertiveness, talkativeness, curiosity, [and] openness in expressing negative feelings.”

The Blocks’ experiment suggested that the roots of our political orientations emerge as early as the fourth year of life. But it raised further, essential questions: Would children from different regions or socioeconomic backgrounds diverge into similar personality groups? And how much deeper are the origins of these crucial personality traits?

When the Blocks’ findings are connected with other relevant studies in genetics, neuroscience, and anthropology, a composite image of our political nature begins to emerge. As this portrait of ourselves comes into focus, it shows what made some of those nursery-school children grow up to become liberals and some of them conservatives. It shows how deep the roots of our political proclivities extend, and why they have a similar influence on children in America, the Middle East, and most everywhere else.

The reason for these crosscutting commonalities is that political orientations are natural dispositions that have been molded by evolutionary forces. Taken together, those deeply ingrained political orientations form what could be called “The Universal Political Animal.”

The Deepest Origin

To begin with, exactly how far down do the roots of preschoolers’ political orientations extend? Do these roots somehow spring from the hard wiring they were born with? Perhaps W. S. Gilbert, the 19th-century English dramatist and poet, was onto something when he mused:

I often think it’s comical
How nature always does contrive
That every boy and every gal
That’s born into this world alive
Is either a little Liberal
Or a little Conservative

In the early 1990s, the University of Minnesota’s Center for Twin and Family Research set out to test Gilbert’s humorously posited theory. Armed with a valuable list of 10,000 twin pairs and their family members, these scholars had a unique way to determine whether our genes—as opposed to our environment—exert any effect over our political convictions.

The Minnesotan scientists began their study with a left-right political-orientation test called the RWA Scale. They handed it out to more than 1,400 identical and fraternal twins. Each pair was raised in the same family. In a parallel study, psychologist Thomas Bouchard gave the same test to a very special subset of siblings: 88 identical twins and 44 fraternal twins raised in completely different environments.

Comparing both types of twins is crucial: In the case of twins raised together, the shared environment (such as family dynamics, interactions between twins, and social perceptions) could influence the development of the twins’ personalities. But for twins separated at birth, most of these confounding factors drop away; this makes it easier to chalk up their personality similarities to genetics.

Figure 1 shows the correlations between the left-right orientations of twins raised together and apart. The black bars correspond to identical twins, and the gray bars to fraternal twins. The first two clusters show the twins raised together. Identical twins (who share 100 percent of their genes) had more similar political orientations than fraternal twins (who share only 50 percent of their genes, like normal siblings).

The third cluster shows the amazing finding of Bouchard’s survey: Identical twins reared apart had a strong correlation between their political orientations; but the scores of fraternal twins raised separately didn’t correlate significantly. These results suggest that genetics plays a decisive role in determining political attitudes. In other words, identical twins are more likely than fraternal twins to agree on divisive issues, precisely because they’re more closely related to one another.

To make this idea more concrete, let’s consider a few specific hot-button issues: “capitalism,” “segregation,” and “immigration.” These three words come from the 28 items on the Wilson-Patterson Conservatism Scale, which political scientist John Alford has researched at Rice University. These terms are guaranteed to set off the hidden triggers of political polarization. In the first case, conflicting attitudes toward “capitalism” are essentially what have divided Tea Partiers from Occupiers. Why? Because unfettered free markets reflect and create inequalities, to which people have varying levels of tolerance, depending on their political leanings. Words like “segregation” and “immigration,” on the other hand, evoke opposing attitudes toward tribalism. People’s attitudes toward inequality and tribalism constitute two of the three clusters of measurable personality traits that give rise to political orientations across space and time (the third cluster concerns differing perceptions of human nature).

In 2005, Alford asked 9,000 identical and fraternal twins to agree, disagree, or express their uncertainty toward these three words and 25 others like them. Positive responses to half of the 28 items raise one’s conservatism score, and positive responses to the other half lower one’s score. Negative reactions do the opposite.

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Avi Tuschman is the author of Our Political Nature: The Evolutionary Origins of What Divides Us. A former adviser to the president of Peru, he is based in Washington, D.C.

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