Personality is often seen as shaped by family life, stress, and lived experience.
However, new scientific evidence suggests genetics also play a significant role in shaping personality.
Here's what to know
Using the biggest dataset yet assembled for the purpose, scientists identified 1,260 genetic markers that influence the so-called Big Five personality traits: extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience.
As Earth.com reported, the analysis drew on 46 separate groups and, depending on the trait being studied, included between 611,037 and more than 1.13 million participants.
Because participants provided both questionnaire-based personality measures and genetic data, the researchers could test millions of small DNA variations against personality scores to look for connections.
That process turned up 1,260 associations, including 824 that had not been reported before, per Earth.com.
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"There is no single 'personality gene,'" explained Ted Schwaba, lead author of the study and a faculty member in the Department of Psychology at Michigan State University, per Earth.com. "Personality traits are associated with many genetic variants, but even the largest effects of individual genetic variants are still very small."
However, when taking into account more than 1,000 genetic variants, those small impacts can really add up.
More background
The study, published in the journal Nature, found that common DNA differences explained only a modest share of personality variation — roughly 5% to 9% in the primary analysis, rising to roughly 9% to 13% after researchers adjusted for measurement error in personality questionnaires.
Both of these figures are significantly lower than the 40% to 60% estimates often reported in twin and family studies, which can capture other kinds of genetic effects.
Researchers also tested whether the same patterns appeared across different ages, regions, and personality tests. While most of the patterns held up, the researchers found that the trait of agreeableness was less consistent.
Importantly, the study's authors noted that about 95% of participants were of European genetic ancestry, meaning the findings may not apply equally to other populations.
Personality traits can have an enormous impact on every aspect of a person's life, from interpersonal relationships to career success.
For example, the team found that genetic patterns tied to conscientiousness were linked to lower substance use, greater sports activity, reduced hospital use, lower body weight, and healthier aging.
Similarly, genetic patterns tied to neuroticism were associated with anxiety- and depression-related mental health conditions.
The researchers stressed that these genetic correlations do not mean that the environment has no impact on personality traits, with life experiences still having a powerful role in shaping personality.
Understanding the important part that both genetics and experience play in shaping personality can have wide-ranging benefits, from helping individuals to better understand themselves to developing new approaches to mental-health challenges.
"Personality seems to be relevant nearly everywhere you look," Schwaba said, per Earth.com.
Where can I learn more?
Personality is just one example of how health and behavior are shaped by a combination of complex forces. The following articles explore how these commingling forces play out in real-world settings, from pollution-linked cancer patterns to the public-health effects of energy policy.
• Across Eastern Europe, energy policy is widening a striking public-health gap between countries.
• Scientists say air pollution is shifting which lung cancer types now dominate.
• Researchers warn climate change is weakening vaccine protection as heat and instability rise.
• In Maine, Lyme disease cases are climbing as tick conditions become more favorable.
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