A massive genetic analysis has identified hundreds of specific DNA variations tied to human personality. The findings suggest that the genetic basis of personality is highly consistent across different populations and is not heavily skewed by a person’s family environment. The research was published in Nature.
Massive GWAS links hundreds of genetic variants to personality
Personality is typically understood through the Big Five framework: extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience. These traits are relatively stable over a person’s life and shape important outcomes such as health, career success and well-being.
Scientists know genetics play a role in shaping personality, but the precise mechanisms are complex. The study used a genome-wide association approach, scanning the genetic code of many people to identify common single-letter changes in DNA that occur more frequently in those with certain traits.
The research team, led by Ted Schwaba of Michigan State University alongside Michel G. Nivard and Elliot M. Tucker-Drob, sought to test how robust these genetic associations are and whether they reflect direct biological inheritance rather than environmental confounding. They also referenced prior work suggesting environmental confounding can inflate genetic links for some social traits, such as educational achievement.
The researchers pooled data from 46 different study cohorts across several countries, with the total sample size ranging from roughly 611,000 to over 1.14 million participants for each of the Big Five traits. Participants provided DNA samples and completed validated personality surveys.
From this enormous dataset, they identified 1,260 genome-wide locations associated with the Big Five traits, of which 824 had not been previously linked to personality variation. Each variant exerts a tiny effect, but together they explain between 4.8 percent and 9.3 percent of the variance in personality across the population.
The genetic signals were remarkably consistent across groups. Similar patterns appeared in populations in the United States, Europe and Australia, and across different age groups. The associations held steady regardless of whether personality was measured by self-report or by a close friend’s rating.
To test whether family environments distorted the findings, the researchers analysed genetic data from thousands of siblings. As siblings share parents and upbringing, this within-family comparison isolates direct genetic effects. The associations for personality changed little within families, suggesting the architecture is driven mainly by direct biological inheritance rather than parental environments.
The study also examined whether people tend to pair with partners who share similar genetics for personality. While a prior meta-analysis suggested some assortative mating, this study found only minimal genetic similarity for personality between spouses, implying that people do not typically select partners based on specific personality-related genetic profiles.
For understanding causality, the researchers used a method that leverages genetic data to test for cause-and-effect relationships. They found evidence that personality traits influence a broad range of behaviours and physical health. For example, a genetic profile linked to higher conscientiousness was associated with a lower body mass index and a reduced likelihood of starting smoking. Similarly, a profile linked to higher neuroticism was associated with a lower chance of healthy ageing.
Conversely, the results suggest that factors like educational attainment and BMI changes can in turn influence average levels of certain personality traits, highlighting a dynamic interplay between life experiences, physical health and biology.
“To me it is incredibly exciting to see such a huge genome-wide association study of personality,” Jasmin Wertz, a researcher at the University of Edinburgh who was not involved in the study, told PsyPost. “Personality traits are some of the most fundamental psychological axes on which people differ, but until now we did not have such a large-scale genomic investigation of these traits, similar to what has already been done for other key traits and behaviors. I think it is also impressive from a team science perspective, because the study brings together so many investigators and cohorts to advance the science.”
“This paper offers a compelling illustration of how complex human traits, like personality, are shaped by many many genes, and each one makes a small contribution to a person’s thoughts, feelings, and behaviors,” said Paul W. Eastwick, a professor in the Department of Psychology at the University of California, Davis who was not involved in the research. Eastwick, the author of Bonded by Evolution and host of the Love Factually podcast, added, “There is no single ‘gene for’ something as complex as personality; instead, genes play an important role in the aggregate.”
Wertz noted that the study’s enormous sample size and the inclusion of different measurement contexts give the results considerable weight. “The findings appear very robust,” she said. “The authors also add a within-family analysis, which shows that the genetics associated with personality are predictive even within siblings raised in the same family, and this analysis helps rule out many of the possible confounding influences that may be present when analyzing unrelated individuals.”
She also pointed out how the findings on romantic partners extend existing knowledge. “One notable finding was that assortative mating – the tendency of people to pick romantic partners they resemble – was very low in this study,” Wertz explained. “It doesn’t necessarily challenge previous findings, because the degree of spousal similarity in personality is not that high in other samples either, but it is an interesting extension using this unusually large genetic study.”
As with all research, there are caveats. The genetic scores from this study cannot predict an individual’s personality or future behaviour; these associations operate as probabilities across groups, not deterministically for any single person.
“General readers often think of genetic influences as implying that something is set in stone, and that is certainly not the right takeaway from this, as well as other, genetic studies,” Wertz told PsyPost. “The genetic influences identified here, as well as in previous studies of personality, are far from 100%, leaving much room for non-genetic influences. In addition, even the genetic influences that have been observed likely interact with a person’s environment in shaping their personality.”
Indeed, the 4.8 to 9.3 percent heritability found here—covering common genetic variants—must be considered alongside higher estimates from other methods. Previous work using different approaches, such as studies involving identical twins, suggests genetics account for roughly 40 to 60 percent of personality differences. That implies rare variants and complex gene interactions likely account for the remainder of biological influence.
Ultimately, while the study finds genetic associations for personality are relatively robustly unconfounded by family environment, a person’s surroundings still play a major role in development. Wertz said she hopes the new genetic tools will help unravel that process, pointing to polygenic scores—single numbers estimating trait likelihood based on thousands of variants—as a promising avenue for future work in how personality develops and relates to health and employment outcomes.
The study, led by Ted Schwaba and colleagues, is titled “Robust inference and correlates from genetic associations with personality.”
