How Much of Your Personality Is Genetic?

For decades, psychologists have sorted human personality into the “Big Five” traits: openness, conscientiousness, extroversion, agreeableness and neuroticism. We’re also all a blend of nature and nurture, but if you’re anything like me, you’ve long wondered how much of your personality is tied to DNA. Considering the stories of children accidentally switched at birth, I often think of this pair of siblings separated at birth, who, though loved by their unwitting adoptive families, stood out like “oddballs” in their family units until reuniting with their immediate biological relatives.

Stories like theirs make it tempting to chalk personality up to nature alone. But a sweeping new study published in Nature this month suggests that the truth is more tangled, Smithsonian magazine reports. Researchers pooled 46 groups of participants — between 611,000 and 1.14 million people who had both submitted DNA and taken personality questionnaires — and scanned their genomes for patterns. They surfaced more than 1,260 common genetic variants tied to at least one Big Five trait, over 800 of which had never been identified before.

The variants the researchers found tracked with real-world outcomes. People carrying extroversion-linked variants were more likely to catch COVID early in the pandemic. Those with agreeableness variants were less likely to be suspended from school or run away from home. High-conscientiousness-variant carriers showed less substance use, more time playing sports, fewer hospital stays and healthier aging.

One finding in particular stood out to Dalton Conley, a Princeton sociologist who wasn’t involved in the research. The data challenged a long-held assumption that neuroticism is driven largely by serotonin, the mood-related brain chemical many antidepressants target. “I wouldn’t say it’s slaying that theory forever,” he said, “but it’s definitely casting doubt.”

Still, researchers say, you can’t predict personality from genes — so don’t go assigning all your interests and behaviors to your parents or grandparents just yet.

Genetics explains only 5 to 13% of personality variance from person to person, depending on the measurement. The rest comes down to environment, experience and everything else that shapes a life. So why the excitement? Well, mapping the variants provides scientists new tools to study how our traits connect to health and behavior across whole populations – and hopefully to ask better questions about where conditions like anxiety and depression truly begin.