Why does one person light up a crowded room while another would rather spend a quiet evening in? A study published in Nature offers a detailed look at personality genetics, drawing on data from more than 1 million people. Among them are 23andMe members who consented to participate in research and answered questions about their personalities. Their contributions helped make this one of the largest studies of its kind.
Is Personality Genetic?
Yes, in part. Your genes play a real but modest role in personality. This study looked to find genetic variants linked to the Big Five.
The Big Five personality traits are five broad dimensions that psychologists use to describe how people differ from one another:
- Extraversion covers sociability, assertiveness and energy level.
- Agreeableness reflects compassion, respectfulness and trust.
- Conscientiousness describes organization, productiveness and responsibility.
- Neuroticism captures a tendency toward anxiety, low mood and emotional ups and downs.
- Openness to experience reflects imagination, curiosity and an appreciation for art and beauty.
Each trait is a spectrum, and most people land somewhere in the middle.
Researchers combined data from 46 study groups, totaling between 611,037 and 1.14 million people per Big Five personality trait. They ran genome-wide association studies (GWAS), which scan millions of points across the genome to find genetic variants that are more common in people who score higher or lower on a trait. They identified 1,260 genetic variants linked to the Big Five.
Of the 1,260 variants, 824 had never been linked to personality before. For example, before this study the number of genetic variants associated with conscientiousness was 3, this study identified 131 variants. For neuroticism, the number of genetic variants rose from 224 to 706.
Personality is polygenic, meaning thousands of variants — each with a tiny effect on its own — work together to influence it. All together, the common genetic variants identified in this study explained about 5 to 9 percent of the differences in personality between people.
That leaves plenty of room for everything else to influence your personality. As the study authors put it, “all methods find that personality is substantially influenced by a person’s environment.” Your experiences, relationships and choices shape your personality too.
Why These Genetic Findings Hold Up
The genetics associated with personality were consistent across countries, age groups and even who was describing the person.
The researchers found similar genetic associations in the United States, continental Europe, the Nordic countries, the UK and Australia. The patterns also held across age groups and different personality questionnaires. In one group from Estonia, people rated their own personalities and close friends or family members rated them too. The genetic results lined up well between the two, which suggests these genetic variants are associated with real personality differences and not just how people see themselves.
Most participants in this research were of European descent. Genetic predictions built mainly from people of European descent usually work less well for other groups. However, this study included about 43,000 to 48,000 people of African descent per trait. This allowed the researchers to show for the first time that genetic scores could predict extraversion, neuroticism and openness in people of African descent, though the predictions were less strong compared to people of European descent.
How Personality Genetics Connects to Health and Other Traits
The researchers measured how much the genetic influences of personality overlapped with everyday health habits and even the kinds of neighborhoods people choose.
The researchers found evidence that higher conscientiousness may lower body mass index (BMI), reduce the likelihood of starting to smoke and reduce hospital stays. The same analyses suggested that extraversion may increase the likelihood of COVID-19 infection, and that higher neuroticism may relate to less healthy aging.
Personality genetics even showed up on the map. Among 419,261 UK Biobank participants, the researchers looked at where people lived at age 50 and older, accounting for where they were born. People with a higher genetic likelihood of openness to experience were more likely to have moved into cosmopolitan, professional neighborhoods and away from the suburbs. People with a higher genetic likelihood of conscientiousness were more likely to have moved into suburban communities.
It’s important to remember that the genetics discovered in this study only represent a small contribution to personality and describe patterns across large groups. They cannot predict an individual’s behavior. Your genes may nudge you toward certain tendencies, but your experiences, relationships and choices all play a role in who you become.
Studies like this depend on people who share their data for research. Find out how you can make a difference here.
