Researchers find higher intelligence is correlated with left-wing beliefs and seems to be genetic

In a world increasingly shaped by political polarization, it’s easy to view ideology as a product of culture, community, or circumstance. But what if part of what influences our political beliefs lies not in where we were raised or what we’ve experienced—but in how our brains are wired to think?

A new study published as part of the Genetics and Human Agency initiative suggests that intelligence—both measured through IQ tests and encoded in our DNA—may play a significant role in shaping political views. Drawing from data on over 300 biological and adoptive families, researchers found consistent links between higher cognitive ability and a tendency toward socially liberal, less authoritarian beliefs. More notably, these findings held true even when controlling for shared environments and socioeconomic factors.

This isn’t about labeling one ideology as smarter than another. Rather, it’s about exploring how certain cognitive traits may influence the way individuals interpret social issues, engage with complexity, and navigate the values that define our political landscape.

A Grounded Approach – How Intelligence and Politics Were Studied

Understanding the relationship between intelligence and political orientation requires more than surface-level correlations—it demands rigorous design, objective measurements, and careful control of external influences. That was the approach taken in a recent landmark study titled Predicting political beliefs with polygenic scores for cognitive performance and educational attainment, which employed both biological and adoptive family data to isolate the influence of intelligence on political beliefs.

The research, conducted under the umbrella of the Sibling Interaction and Behavior Study (SIBS), drew from over 300 families—biological and adoptive—making it uniquely positioned to account for genetic and environmental variables. The longitudinal data, collected between 2017 and 2023, was originally part of a broader behavioral genetics initiative, supported by institutions including the National Institutes of Health and the John Templeton Foundation.

What set this study apart was its twin-pronged approach to measuring intelligence. Researchers used both phenotypic IQ—measured through traditional intelligence testing—and polygenic scores, which are based on genetic variants statistically associated with cognitive performance and educational attainment. This allowed the team to distinguish between intelligence as expressed behaviorally and its underlying genetic architecture.

In addition, the study implemented a within-family design, a powerful tool in behavioral genetics that compares siblings within the same family to minimize the influence of shared environmental factors. This method is particularly valuable in controlling for socioeconomic conditions, parenting styles, and cultural background—factors that often blur the lines in broader population studies.

By standardizing IQ and political beliefs, and applying robust statistical controls, the researchers were able to assess associations with a high degree of confidence. Across the board, both measured IQ and polygenic scores significantly predicted responses on six political attitude scales, which included dimensions like social liberalism, authoritarianism, and broader ideological leanings.

Intelligence and Political Beliefs – What the Data Reveals

The results of the study present compelling evidence of a consistent link between intelligence and left-leaning political beliefs—across both genetic and measured indicators of cognitive ability.

At the core of the findings was a clear pattern: individuals with higher IQ scores and those with higher polygenic scores for cognitive performance and educational attainment were more likely to express political views associated with social liberalism and lower levels of authoritarianism. These results were statistically significant across all six political attitude scales the researchers examined.

What makes these results particularly noteworthy is that the correlation persisted even after controlling for socioeconomic and environmental variables, such as family income, education level, and home environment—factors that have historically complicated the interpretation of such studies. The within-family design ensured that even siblings raised under the same roof, with access to the same resources, still displayed meaningful political differences aligned with their individual cognitive profiles.

Furthermore, the use of polygenic scores added a powerful layer of genetic insight. These scores, derived from large-scale genome-wide association studies (GWAS), aggregate small effects across many genes associated with educational success and general intelligence. When applied to political belief scales, these scores predicted a statistically significant tilt toward progressive and non-authoritarian viewpoints.

Importantly, the results support a causal inference—that is, the suggestion that intelligence may not just correlate with, but actually shape, political beliefs. This doesn’t mean intelligence “determines” ideology in a simplistic way. Rather, it suggests that people with higher cognitive ability may be more likely to process complex social information, evaluate multiple perspectives, and adapt to abstract or evolving societal norms—traits that tend to align with liberal values in current Western political contexts.

Contextualizing the Findings – Intelligence Through the Lens of Political Psychology

The idea that intelligence correlates with political ideology is not new—but this study provides one of the clearest validations of the theory to date. In political psychology, a longstanding hypothesis holds that cognitive ability influences openness to new experiences, complexity in thought, and tolerance for ambiguity—all traits commonly associated with liberal ideologies.

This aligns with the “Openness to Experience” dimension of the Five-Factor Model of personality, a well-documented predictor of liberal social attitudes. Individuals high in openness are typically more receptive to novel ideas and less reliant on rigid traditional structures. Intelligence, as measured both phenotypically and genetically, has been shown to correlate with this same personality trait in prior research, offering a possible psychological mechanism behind the study’s findings.

Similarly, the findings resonate with Terror Management Theory (TMT) and Right-Wing Authoritarianism (RWA) frameworks. These models suggest that individuals with lower tolerance for uncertainty or cognitive complexity are more inclined toward authoritarian or conservative positions, which emphasize order, tradition, and stability. By contrast, those with higher cognitive ability may be more adept at coping with societal ambiguity and change, leading to greater support for civil liberties, social equity, and pluralism.

However, these insights should not be taken to imply a moral or intellectual superiority of one political orientation over another. Intelligence may influence the kinds of values a person emphasizes—such as fairness versus loyalty, or liberty versus authority—but it does not dictate the entirety of a worldview. As political psychologist Jonathan Haidt notes, both liberal and conservative ideologies can be rooted in deeply held moral intuitions, shaped by personal experience, community, and culture.

Distinguishing Nature from Nurture – The Role of Genetics and Environment

A central strength of this study lies in its innovative approach to teasing apart the long-debated influences of nature and nurture on political beliefs. By combining measured intelligence (phenotypic IQ) with polygenic scores, and applying a within-family design, the researchers were able to reduce environmental confounds to a minimum—bringing rare clarity to a complex subject.

Polygenic scores, in this context, are aggregated indicators based on thousands of genetic variants statistically associated with cognitive performance and educational attainment. These scores are not predictive of political beliefs directly, but rather of traits that influence how individuals might think about the world—traits such as analytical reasoning, abstract thinking, and long-term planning. By correlating these scores with responses to political attitude scales, the researchers found that even when controlling for socioeconomic background and shared family environment, genetic indicators of intelligence still predicted more liberal and less authoritarian views.

The inclusion of adoptive families was crucial. Unlike biological siblings, adoptive siblings share no genetic material but often experience similar family environments. In both biological and adoptive family comparisons, the relationship between cognitive ability and political ideology remained evident—signaling that the effect was not merely due to shared upbringing or socioeconomic factors.

This within-family framework addresses a common critique of behavioral genetics: that observed associations often reflect uncontrolled environmental variables like parental influence or education quality. Here, siblings served as each other’s control group. By comparing individuals who grew up in the same household but differed in cognitive ability (either genetically or in measured IQ), the researchers could more confidently isolate intelligence as a contributing factor to ideological differences.

Intelligence, Ideology, and the Complexity of Belief

The findings of this study offer a nuanced window into the relationship between human cognition and political orientation—one that resists sensationalism but rewards careful consideration. By leveraging a rare within-family design and integrating both measured IQ and genetic data, the researchers have moved the conversation beyond mere correlation and toward a more evidence-based understanding of how intellectual traits may influence ideological leanings.

The takeaway is not that intelligence determines one’s politics, but that it may shape how individuals process political information—how they weigh evidence, navigate ambiguity, and prioritize competing values. Higher cognitive ability appears to correlate with greater openness to socially liberal and less authoritarian viewpoints, even when genetic and environmental factors are held constant. This relationship is not absolute, and it does not devalue other ideological perspectives, but it adds texture to our understanding of what informs political belief.

Just as intelligence is a multidimensional trait, so too is ideology a complex, evolving construct. The study’s implications are not deterministic but descriptive—inviting further exploration into how individuals come to see the world not only through the lens of their upbringing or social surroundings, but also through the architecture of their cognition.