Can your personality type change? What longitudinal research shows
By the 64 Types team · Updated October 13, 2026 · 6 min read · 9 peer-reviewed sources
Yes. Personality is fairly stable, but it is not fixed. Your position relative to other people becomes more consistent with age,[1] yet average trait levels shift across adulthood: most people become more conscientious, more emotionally stable and more socially confident, especially between 20 and 40.[2] Traits also change with intervention. A review of 207 studies found marked changes over an average of 24 weeks, mainly in emotional stability,[3] and randomised trials show that people who set out to change a trait can shift it measurably in a few months.[4][5]
Your type code can also change for a simpler reason: if you sit near the middle of a trait, small differences between test sessions flip the letter. This guide covers both.
Two kinds of stability
Researchers separate two questions that are easy to blur together:
- Rank-order stability: do people keep their position relative to others? If you were more conscientious than most of your classmates at 20, are you still at 50?
- Mean-level change: does the average level of a trait rise or fall over time, for everyone together?
Both can be true at once. A whole cohort can become more conscientious with age (mean-level change) while individuals mostly keep their rank within it (rank-order stability).
Rank-order stability grows with age
A meta-analysis of 152 longitudinal studies compiled more than 3,200 test–retest correlations. Holding the gap between measurements constant at about 6.7 years, consistency rose from .31 in childhood to .54 in the college years, .64 at age 30, and a plateau of around .74 between ages 50 and 70. Longer gaps between measurements meant lower consistency.[1]
| Age period | Test–retest correlation |
|---|---|
| Childhood | .31 |
| College years | .54 |
| Around 30 | .64 |
| 50 to 70 | about .74 |
Even the plateau is well below 1.0. A correlation of .74 means people stay broadly in place, but plenty of individuals move noticeably relative to their peers.
How traits change across the lifespan
A meta-analysis of 92 longitudinal samples mapped how average trait levels change from adolescence to old age.[2]
| Trait | Typical pattern |
|---|---|
| Conscientiousness | Increases, especially from about 20 to 40 |
| Emotional stability | Increases, especially from about 20 to 40 |
| Social dominance (assertive side of extraversion) | Increases, especially from about 20 to 40 |
| Social vitality (sociable side of extraversion) | Increases in adolescence, decreases in old age |
| Openness | Increases in adolescence, decreases in old age |
| Agreeableness | Changes mainly in old age |
Four of the six trait categories also changed significantly in middle and old age, so personality development does not stop at 30.[2]
In 64 Types terms, this means the J/P and C/R letters are the ones most likely to drift over adulthood, generally toward J (organised) and C (composed).
Therapy and other interventions change traits
A systematic review of 207 studies, mostly of clinical treatment, found that interventions were associated with marked changes in personality trait measures over an average of 24 weeks (for example, d = .37). Emotional stability changed the most, followed by extraversion. The type of therapy made little difference, people treated for anxiety changed most, and the changes persisted in follow-ups after treatment ended.[3]
This is one of the most hopeful findings in personality science. High neuroticism is strongly linked to anxiety and depression,[6] and it is also the trait that responds most to treatment. See Neuroticism and emotional stability.
Can you change your personality on purpose?
Most people say they would like to change some of their traits.[4] Two 16-week randomised experiments tested whether wanting to change makes a difference. People who set goals to increase a Big Five trait tended to show actual increases in their self-reports and in trait-relevant daily behaviour. One intervention to help them did not work, but a second, which trained participants to write specific if–then plans (implementation intentions), did help them change.[4]
A larger randomised trial with 1,523 participants tested a three-month smartphone coaching app. Compared with a waitlist control group, people who wanted to increase a trait reported meaningful increases (d = 0.52), and friends, family or partners also noticed changes in the desired direction (d = 0.35). Changes held up three months after the programme ended. Observer-reported change was not significant for people trying to decrease a trait.[5]
These are average effects from motivated volunteers, mostly measured by self-report. They show that change is possible, not that any trait can be rewritten at will.
How to change a trait: an evidence-informed approach
- Pick one trait and a concrete direction. For example, “be more organised at work” rather than “be a better person”.
- Translate it into behaviour. Traits are patterns of behaviour; change the behaviour and the trait tends to follow. Studies of volitional change measured both.[4]
- Write if–then plans. “If it is 9:00 on Monday, then I plan the week before opening email.” This was the technique that worked in the randomised trial.[4]
- Practise for months, not days. The successful programmes ran for 16 weeks to three months.[4][5]
- For anxiety or low mood, use proven treatment. Therapy produced the largest trait changes in the review, especially for emotional stability.[3]
| Goal | Example if–then plan |
|---|---|
| More organised (toward J) | If I finish a work session, then I write down the next step before closing the laptop. |
| Calmer (toward C) | If I notice I am catastrophising, then I write the worry down and the next concrete action. |
| More outgoing (toward E) | If I arrive at a social event, then I introduce myself to one new person in the first ten minutes. |
| Warmer (toward F) | If a colleague shares a problem, then I ask one question about how they are before offering a fix. |
| More curious (toward N) | If I have a free Sunday afternoon, then I try one exhibition, book or recipe I would normally skip. |
Ask someone who knows you well whether they have noticed a difference after a few months. In the app trial, observers detected real changes,[5] and outside feedback guards against simply describing yourself differently.
Stable enough to matter, flexible enough to change
Both halves of the evidence matter. Personality is stable enough that traits measured today predict outcomes years later, such as mortality, divorce and occupational attainment, about as well as socioeconomic status and cognitive ability do.[7] Yet it is flexible enough that age, therapy and deliberate practice all move it.[2][3][5]
A useful way to hold both ideas: your traits describe your current defaults, the way you tend to act when you are not making a special effort. Defaults are hard to change in a week and quite possible to change over months or years.
Why your type code may change on a retest
Most retest changes in four-letter codes are not personality change at all. Trait scores cluster near the middle,[8] and anyone near a cut-off can flip a letter because of ordinary measurement error, which reviews of the MBTI identify as a key weakness of type formulas.[9]
64 Types reports a percentile for each trait and flags anything within 10 points of average as borderline, together with the alternative code you could get next time. If your INFP-RM became INFJ-RM and your J/P score is at the 52nd percentile, nothing important changed. See Are personality tests accurate?
Frequently asked questions
At what age does personality stop changing?
It never fully stops. Consistency peaks around .74 between ages 50 and 70,[1] and four of six trait categories still change in middle and old age.[2]
Which personality trait changes most?
Over the lifespan, conscientiousness, emotional stability and social dominance rise most clearly in young adulthood.[2] In response to therapy, emotional stability changes most.[3]
Can therapy change your personality?
Yes, on average. Across 207 studies, interventions were linked to marked trait changes over about 24 weeks, mostly in emotional stability, and the changes persisted after treatment.[3]
References
- Roberts, B. W., & DelVecchio, W. F. (2000). The rank-order consistency of personality traits from childhood to old age: A quantitative review of longitudinal studies. Psychological Bulletin, 126(1), 3–25.
- Roberts, B. W., Walton, K. E., & Viechtbauer, W. (2006). Patterns of mean-level change in personality traits across the life course: A meta-analysis of longitudinal studies. Psychological Bulletin, 132(1), 1–25.
- Roberts, B. W., Luo, J., Briley, D. A., Chow, P. I., Su, R., & Hill, P. L. (2017). A systematic review of personality trait change through intervention. Psychological Bulletin, 143(2), 117–141.
- Hudson, N. W., & Fraley, R. C. (2015). Volitional personality trait change: Can people choose to change their personality traits? Journal of Personality and Social Psychology, 109(3), 490–507.
- Stieger, M., Flückiger, C., Rüegger, D., Kowatsch, T., Roberts, B. W., & Allemand, M. (2021). Changing personality traits with the help of a digital personality change intervention. Proceedings of the National Academy of Sciences, 118(8), e2017548118.
- Kotov, R., Gamez, W., Schmidt, F., & Watson, D. (2010). Linking "big" personality traits to anxiety, depressive, and substance use disorders: A meta-analysis. Psychological Bulletin, 136(5), 768–821.
- Roberts, B. W., Kuncel, N. R., Shiner, R., Caspi, A., & Goldberg, L. R. (2007). The power of personality: The comparative validity of personality traits, socioeconomic status, and cognitive ability for predicting important life outcomes. Perspectives on Psychological Science, 2(4), 313–345.
- Bess, T. L., & Harvey, R. J. (2002). Bimodal score distributions and the Myers-Briggs Type Indicator: Fact or artifact? Journal of Personality Assessment, 78(1), 176–186.
- Pittenger, D. J. (2005). Cautionary comments regarding the Myers-Briggs Type Indicator. Consulting Psychology Journal: Practice and Research, 57(3), 210–221.
How we write guides: every research claim cites a peer-reviewed source, effect sizes are reported as published, and advice that goes beyond the evidence is labelled as a practical tip. See our methodology. Found an error? Email [email protected].
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