Personality influences how people think, feel, behave, and interact with the world around them.
Credit: PeopleImages/Getty
A genetic study of more than 1 million people has identified approximately 1,200 genetic variations linked to personality traits, making it the largest genome-wide association study (GWAS) of personality conducted to date.
The research examined the genetic basis of the “Big Five” personality traits: extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience. The findings show that common genetic differences explain only a modest share of personality variation within a population.
Although the genetic links were relatively small, they were stronger for factors such as family background than for education, income, and several other social and behavioral characteristics. Researchers also used genetic correlations to investigate relationships between personality traits and health or lifestyle outcomes. These included the likelihood of starting to smoke, which was associated with conscientiousness; the risk of contracting COVID-19, which was associated with extraversion; and participation in research, which was linked to agreeableness and openness to experience.
“Personality is central to many aspects of human life and health,” said Michel Nivard, a genetic epidemiologist at the University of Bristol in the United Kingdom, who co-led the study. Nature1 However, the researchers cannot yet determine whether personality directly causes these outcomes. “We want to show that genomic data can help us begin to study these relationships,” he added.
“Researchers have been waiting for a large and reliable genome-wide association study of personality,” said behavioral geneticist Ais Okbay of Amsterdam University Medical Center. “Genetic research on personality has lagged behind studies of many other important behavioral traits.”
Large-scale genetic study reveals links to Big Five personality traits
Like most human characteristics, personality develops through the interaction of genes and the environment. However, identifying genetic variants that can be reliably associated with personality has been difficult because many large genomic databases lack consistent personality measurements.
To address this challenge, an international research group known as the Revived Genomics of Personality Consortium combined data from 46 cohorts. Depending on the trait and analysis, the dataset included between 611,000 and 1.14 million participants.
Participants completed standardized personality questionnaires, such as those available through personalitylab.org. Psychologists use these assessments to measure the Big Five traits and the narrower characteristics associated with each trait. The researchers also provided an FAQ document explaining the study and its methods. Although personality tests are not the only way to assess behavior, they remain widely used in psychological research, despite ongoing debate about their accuracy and limitations.
Ambitious study of human diversity uncovers millions of undiscovered genetic variations
The analysis identified 1,260 common genetic variations associated with at least one of the Big Five personality traits. More than 800 of these variants had not previously been reported. For conscientiousness, the number of associated variants rose from 3 to 131, while the number linked to neuroticism increased from 224 to 706. Depending on the trait and analytical method, common genetic variants explained approximately 5% to 16% of the differences observed among participants.
Researchers emphasize that each individual genetic variant has only a very small influence on personality. For example, the average genetic variant associated with higher extraversion would shift a person’s score only slightly—roughly from the 50th percentile to the 50.35th percentile.
These findings do not make it possible to accurately predict an individual’s personality from their DNA. “I am not interested in predicting personality,” Nivard said. “If you want to understand someone’s personality, the most effective approach is simply to measure it.”
Additional analyses of genetically related participants, including twins, parents, and siblings, provided little evidence that a shared family environment explained the genetic associations with personality.
“I thought there might be an indirect genetic effect, in which a childhood environment shaped by parents’ genes influenced personality,” Nivard said. “But we found no evidence of this gene–environment correlation.” The study also found little support for the idea that people tend to choose partners with personalities similar to their own.
Source: www.nature.com