What did the largest-ever genetic study of personality reveal about the 1,260 genetic variants associated with the Big Five traits—openness, conscientiousness, extraversion, agreeableness, and neuroticism—including the study’s scale and methodology, the very small effects of indi

The study found that personality is highly polygenic: roughly 1,260 common DNA variants were statistically associated with the Big Five, but each has an extremely small effect. Genetics therefore helps describe population-level patterns in personality; it cannot determine, diagnose, or accurately predict one person’s personality. 25

What the study did

• Researchers combined genome-wide association data from 46 cohorts, covering roughly 611,000 to 1.14 million participants with European-like and African-like genetic ancestries, and related millions of DNA markers to questionnaire measures of openness, conscientiousness, extraversion, agreeableness, and neuroticism. 2
• The preprint’s count is 1,257 independent “lead” variants, including 823 not previously reported; contemporary accounts round this to about 1,260. 2
• Common variants collectively explained 4.8–9.3% of observed variation in each trait. Adjusting statistically for unreliability in personality measurement raised the estimate to 10.5–16.2%. 2

Effect sizes and prediction

• No individual variant is a “gene for” being outgoing, anxious, conscientious, or open: the detectable effects of individual markers are minuscule. 2
• Even combined into polygenic scores, these associations accounted for less than about 4% of individual differences in independent prediction samples, so they are not remotely precise enough to infer an individual’s personality from DNA. The large difference between explained variance in the discovery analysis and out-of-sample prediction reflects, among other things, measurement limits and the difficulty of transferring estimates across samples. 2
• Most variation remains attributable to other genetic influences not captured by these common markers, measurement variation, and non-genetic developmental and social environments. This is consistent with the broader evidence that longevity and health, for example, reflect genetics, environment, and lifestyle together. 8

Why this is not just shared upbringing

• The reported genetic associations were highly consistent across geographic settings and whether personality was rated by participants themselves or by informants. 2
• Such replication across reporters and places makes a simple explanation based solely on a shared family environment less plausible. It does not, however, turn the associations into proof that a particular variant directly causes a particular personality trait. 2

Links to life outcomes

The researchers reported genetic correlations—shared statistical genetic influences, not proof that personality genes directly cause outcomes—between the Big Five and many domains, including:

• Physical and mental health, as well as longevity-related outcomes. 24
• Educational attainment and occupational or career-related pathways. 2
• COVID-19 susceptibility or severity-related measures. 23
• Residential and neighborhood-selection patterns, suggesting that genetically correlated personality differences may be related to the environments people tend to enter or remain in. 2

These links should not be read as “a personality gene causes disease, educational success, a job, or a neighborhood.” Genetic correlation can arise through overlapping biology, behavior, social processes, and gene–environment correlation; it does not establish a one-way causal path. 2

The researchers’ central caution

The useful conclusion is about averages across very large groups: DNA variation is one contributor to population differences in broad personality traits. It is not a personality test, a destiny statement, or a means to rank individuals, because each association is tiny and present-day scores have weak individual-level predictive accuracy. 25