By the time people grow into adulthood, they have a pretty good idea of their political affiliation. A twenty-year-old might not be particularly articulate in voicing their political views, but they will nevertheless have some political inclinations that support a certain ideology or political attitude. The question is: how do people develop this? Why do some people lean more liberal while others lean more conservative?

Many factors determine how people participate in their civil rights and what political parties they support. Foremost among these is, by a wide margin, family — specifically the parents who might shape the ideological beliefs of their children during their formative years either directly (e.g., through political discussion) or indirectly (e.g., through modeling). Then you have things like gender, religion, race and ethnicity.

However, a new study would like to point out an often-overlooked factor in this discussion, one that goes beyond upbringing. Researchers have found that both IQ scores and genetic markers associated with intelligence can have a significant role in shaping our political affiliations. The researchers at the University of Minnesota, Twin Cities found that “intelligence is correlated with a range of left-wing and liberal political beliefs.

“Polygenic scores predicted social liberalism and lower authoritarianism, within-families. Intelligence was able to significantly predict social liberalism and lower authoritarianism, within families, even after controlling for socioeconomic variables. Our findings may provide the strongest causal inference to date of intelligence directly affecting political beliefs,” the researchers wrote in the journal Intelligence.

The background of a curious trend

Researchers have proposed various theories about how political beliefs and intelligence interact. For instance, some studies suggest that individuals with conservative ideologies might, on average, have lower intelligence. Conservatives generally value tradition, respect for authority, and social order, and tend to be skeptical of innovation and change. Meanwhile, liberals typically prioritize values such as equality, social justice, and the protection of civil liberties. They are often more open to change and innovation.

These studies argue that the conservative emphasis on maintaining the status quo could reflect cognitive inflexibility, making such ideologies more attractive to those who struggle with intellectual challenges, especially those involving new information. Some evidence indicates that people holding more conservative views typically achieve lower scores on IQ tests and possess lower educational levels.

Other research has produced different views. German-British psychologist Hans Eysenck proposed a theory suggesting that people with higher intelligence tend to avoid extreme political ideologies. According to this theory, smarter individuals are likely to hold moderate or centrist political views. The reasoning behind this is that both right-wing and left-wing extremes are often linked with dogmatism and rigidity, traits that supposedly attract less intelligent people.

German psychologist Heiner Rinderman supports this theory, claiming that intelligent individuals typically hold civic values that drive them to endorse political systems they think will support education and the expansion of knowledge. Therefore, these individuals believe that moderate or centrist parties are better suited to advance their social interests than parties with more defined left or right ideologies.

If you’re a conservative, reading this might make you understandably mad. However, the subject is indeed complex and not fully understood — so take all these claims with a grain of salt.

Shaping political leaning beyond upbringing

For Tobias Edwards, a Ph.D. student in behavioral genetics at the University of Minnesota, Twin Cities, these previous investigations suggest there may truly be a link between intelligence and political orientation. But what has been missing, in his view, is why such a link would exist in the first place. Being the scientist that he is, he set about doing his own investigation.

In this study, Edwards and colleagues examined data from the Sibling Interaction and Behavior Study (SIBS). This dataset is a goldmine for genetic research because it includes a wealth of information about people who have biological, adopted, or mixed siblings. Since these people are raised in the same household, presumably under very similar circumstances in terms of parenting, education, and activities, differences in their behaviors and attitudes can be more reliably pinned to their genetic predispositions rather than the environment.

The study involved 82 pairs of biological siblings, 96 pairs of adopted siblings, and 35 pairs of mixed siblings with one adopted and one biological sibling. Each participant was evaluated with standard IQ tests and had their genome sequenced.

This approach revealed that siblings with higher IQ scores or more favorable genetic markers for intelligence tended to adopt more liberal political beliefs compared to their siblings, irrespective of their shared upbringing. This pattern was observed in both biological and adoptive siblings.

“We find both IQ and genetic indicators of intelligence, known as polygenic scores, can help predict which of two siblings tends to be more liberal,” Edwards told PsyPost.

“These are siblings with the same upbringing, who are raised under the same roof. This implies that intelligence is associated with political beliefs, not solely because of environment or upbringing, but rather that the genetic variation for intelligence may play a part in influencing our political differences. Why is this the case? I do not know.”

Intelligence: just one piece of the political puzzle

The study also explored various facets of political ideology, from authoritarianism to religiousness, and found that both IQ and polygenic scores significantly predicted these political dimensions.

However, Edwards emphasizes the importance of viewing intelligence as just one of many factors influencing political beliefs and warns against judging the merit of ideologies based on the intelligence of their proponents. He calls for humility and tolerance in our political discourse, recognizing that intelligent individuals have historically been divided on issues that may now seem trivial.

“It is very tempting to make inferences to the veracity of an ideology based on the intelligence of its supporters,” Edwards said. “But this would be a mistake. There have been extraordinarily intelligent people on both the left and right, from Oppenheimer to von Neumann. These and many more examples show that there is no reason why we must presume one ideology to be more intelligent than another, even if smart people seem more likely to align with one belief or another.”

“From our study we cannot say that the beliefs of high IQ people tell us what is right to believe, but rather only what smart people choose to believe.”