How Your Personality Trait Scores Change Over Decades

Most people sit somewhere between two beliefs about personality. One is that it is fixed for life. The other is that it changes whenever you want it to. Both are wrong, and the truth in the middle is more interesting than either.

Personality traits are more stable than mood, less stable than height. The clearest map of how they shift across decades comes from a meta-analysis by Roberts, Walton, and Viechtbauer that pooled 92 longitudinal studies covering ten to seventy years of life ¹. The pattern they found has a name: the maturity principle.

The maturity principle, in one paragraph

Across the average life, four of the Big Five traits drift in a direction most cultures would call growing up. Conscientiousness goes up. Agreeableness goes up. Neuroticism goes down. Extraversion is mostly flat, with a small dip late in life. Openness is mostly flat, with a small dip after middle age. The drift is slow, but it is consistent across countries, cohorts, and study designs.

It is not that everyone ends up in the same place. The order between people stays mostly stable — a 20-year-old in the 80th percentile of Conscientiousness tends to be in the 80th percentile at 50. What changes is the whole distribution moves slightly toward more conscientious, more agreeable, less neurotic. Everyone drifts. Most people drift in the same direction.

Conscientiousness: the biggest mover

Of the five traits, Conscientiousness shows the largest average change with age. It rises across the 20s and 30s, more slowly in the 40s and 50s, and plateaus in late middle age.

The mechanism is partly social. Starting a career, taking on a mortgage, raising children, being responsible for other people's outcomes — these are real-world demands that select for and reinforce conscientious behavior. The trait responds. People who scored moderately at 22 often score noticeably higher at 35, not because the test changed but because the daily behaviors did.

This is why "I will be more disciplined in my 30s" is often true even when no one is consciously working on it. The decade does some of the work.

Agreeableness: the slow climber

Agreeableness rises across adulthood, slowly. The change is smaller than the Conscientiousness shift but persists into older age.

Older adults, on average, are more forgiving, more compliant, and more tender-minded than younger versions of themselves. The drop in interpersonal antagonism is one of the cleaner findings in the lifespan literature.

This is also one of the more underrated reasons families get along better in the second half of life. A 60-year-old parent and a 35-year-old child are often easier with each other than the same pair were at 40 and 15. Some of that is circumstance. Some of it is the trait moving.

Neuroticism: the slow drop

Neuroticism falls across most of adulthood. The biggest drop is between the late teens and the early 30s. The decline continues more slowly through middle age and may flatten or slightly reverse in late old age, especially as health changes ².

Most people in their 40s and 50s describe themselves as less anxious, less reactive, and less prone to dark moods than they were at 22. The score data backs this up. The reduction is real and not just self-flattery — informant reports from spouses and friends show the same pattern.

This is one of the most reliably good pieces of news in personality science. If you are 25 and find your emotional volume exhausting, there is a real chance that some of the volume will fade with age, without any intervention. Intervention can speed it up. Time alone moves it too.

Extraversion and Openness: mostly flat

Extraversion and Openness change less than the other three across adulthood.

Extraversion is roughly stable through middle age and shows a small decline in late life, partly as social opportunities shrink. The two facets of Extraversion — the activity-seeking part and the warmth part — move slightly differently, with activity dropping more than warmth.

Openness is also roughly stable, with a small decline after middle age. People in their 70s on average score slightly lower on Openness than the same people in their 40s, though there is wide variation. Continued engagement with new ideas, new people, and new work slows or reverses the drift.

What the research does not say

A few things to be careful about reading into this.

Average drift is not personal destiny. The Roberts and colleagues meta-analysis describes what most people do, on average. Individual paths vary widely. About 25 percent of people show changes in the opposite direction of the population average on at least one trait.

Big life events can override the drift. Divorce, unemployment, serious illness, military service, or moving countries can shift trait scores in ways that swamp the slow age-related drift ³. Personality change is not just a clock running. It is partly the daily environment selecting for some behaviors over others.

Change can be sped up deliberately. Studies on volitional trait change show that people who pick a target trait, set specific behaviors, and stick with them for three to four months see measurable shifts on top of the age drift ⁴. The traits respond to sustained behavior. They do not respond to wanting.

The "order" between people is more stable than the "level." If you are a high-Conscientiousness 20-year-old, you will likely be a high-Conscientiousness 50-year-old. Both of you will have moved up, but you will still be near the top of your age peers. This is called rank-order stability, and it is high — above 0.7 — over long intervals.

How to use this

A few practical reads if you are looking at a current trait score.

At 22, the score is the most volatile it will ever be. Decade-over-decade change in the 20s is the largest in adulthood. A trait pattern you do not like at 22 may not be the pattern you have at 32.

By 45, the score is closer to the long-run number. Trait shifts after middle age are smaller. The version of you in midlife is closer to the version you keep for the rest of life than the version you were at 22.

A score outside your age norm matters more than the raw number. A 45-year-old with a Conscientiousness score in the 30th percentile is far from the typical 45-year-old. A 22-year-old with the same score is closer to typical. The age-corrected reading is the more honest one.

The Defaults assessment shows your scores against age and gender norms, so you can see both where you sit and how unusual that position is for someone like you.

See your scores in context →

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