TL;DR
Yes, personality changes — but not the way self-help promises. Across decades of longitudinal Big Five research, two things are clear: (1) traits are stable enough to be real, with test–retest reliability above 0.80, and (2) they still drift measurably over years. Most adults naturally become more conscientious, more agreeable, and less neurotic with age. Deliberate change is possible too, but it moves on the scale of months and years, not weekends. This is what the evidence actually shows.
"Can I change my personality?" is one of the most-searched questions about personality psychology, and it usually comes loaded with hope or dread — hope that you can fix a trait you dislike, or dread that you are stuck as you are.
The honest answer is more interesting than either. Your Big Five traits are real and stable enough to predict your behaviour years out — and they shift, predictably, across a lifetime. Personality is neither a fixed sentence nor infinitely editable clay. It is somewhere in between, and the science is specific about where.
This article walks through three questions, in order: Do traits actually change? How much, and in which direction? And can you steer it on purpose?
First: are personality traits even stable?
Before asking whether traits change, you have to establish that they are stable in the first place — otherwise "change" means nothing.
They are. Well-built Big Five measures show test–retest reliability above 0.80 over short intervals, and rank-order stability stays high across years. Rank-order is the key concept: if you are more conscientious than your friend today, you will very probably still be more conscientious than them in a decade, even if both of your absolute scores have moved. The ordering of people is remarkably durable.
This is exactly why the Big Five is taken seriously in research and the MBTI is not. A measure that reshuffles people every few weeks — as the MBTI does for roughly 50% of takers — cannot be tracking anything stable. The Big Five clears that bar easily.
Personality is stable enough that your trait ranking among people barely moves in a decade — yet your absolute scores can drift 5–10 points over the same span. Both facts are true at once.
So the question is not "is personality fixed or fluid." It is: given that traits are genuinely stable, how much do they still move, and how?
How traits change on their own: the maturity principle
Here is the finding that surprises people most: personality change is mostly predictable and mostly for the better, and it happens whether you try or not.
The landmark evidence is a meta-analysis by Roberts, Walton & Viechtbauer (2006), which pooled 92 longitudinal studies. Across them, a consistent pattern emerged — researchers call it the maturity principle. As people move through adulthood, on average they become:
- More conscientious — especially through their twenties and thirties, as work and responsibility accumulate
- More agreeable — warmer, more cooperative, less combative with age
- Less neurotic — more emotionally stable, less reactive to stress
- Roughly stable on extraversion and openness, with small late-life declines
These are not trivial nudges. Over a lifetime, the average shift on some traits is comparable in size to half a standard deviation. The twist is that you do not have to do anything for most of it. Taking on a serious job, committing to a relationship, raising a child — these ordinary adult roles pull conscientiousness and agreeableness upward as a side effect.
Why your early-twenties result is a snapshot, not a verdict
If you took a Big Five test at 22 and scored high on neuroticism, that number is not your destiny. The maturity principle predicts that, on average, the same person retested at 35 will score meaningfully lower on neuroticism — often without any deliberate effort. A result is a description of where you are now, not a fixed coordinate. This is also why retaking the test every few years is genuinely informative.
The maturity principle in one picture: across adulthood, average conscientiousness and agreeableness rise while neuroticism falls — mostly without deliberate effort.
Which traits are easiest to shift?
Not all five move equally. If your goal is deliberate change, it helps to know which traits the evidence says are more responsive — and which are more entrenched.
Can you change your personality on purpose?
The natural drift is real, but the more practical question is whether deliberate effort works. The newer research says yes — with caveats.
A growing body of intervention studies shows that targeted, sustained effort can move trait scores beyond what age alone would predict. The pattern across this work is consistent:
- Change is possible but slow. Meaningful shifts show up over months of consistent effort, not days. There is no weekend that rewires a trait.
- Behaviour leads, traits follow. You do not change a trait by deciding to. You change it by repeatedly acting differently until the new pattern becomes automatic — and the trait score follows the behaviour, not the intention.
- Structured beats willpower. The interventions that work give people concrete, repeated "challenges" (small behavioural goals tied to the target trait) rather than vague resolutions.
- Therapy is the strongest lever for neuroticism. Clinical interventions reliably lower trait neuroticism, the single most change-responsive of the five.
What deliberate change is not
It is not a personality transplant. You will not turn a deeply introverted person into a natural extravert, or a low-openness person into an abstract dreamer. Realistic deliberate change means shifting a trait by a band — say, from clearly high neuroticism toward the middle — not flipping it end to end. Aim for "less reactive," not "a different person."
So what should you actually take from this?
Put the evidence together and a balanced picture emerges — one that avoids both the "you're stuck" fatalism and the "rewrite yourself in 30 days" fantasy:
- Your traits are real and stable — stable enough to be worth knowing.
- They also drift naturally, mostly in a positive direction, as you age and take on adult roles.
- Deliberate change is possible, especially for neuroticism, but it works through repeated behaviour over months — not insight or intention alone.
- The realistic unit of change is a band on the scale, not a flip from one pole to the other.
The most useful first step is simply knowing where you stand today. A trait you want to move is far easier to track once you have a baseline. If you have not taken the free Big Five test — seven minutes, no signup — that baseline is the place to start, and you can read how to interpret the scores once you have them.
Get your baseline first
You can't track change without a starting point. The free Big Five test takes about 7 minutes, no signup, and scores you on all five dimensions — retake it in a year to see what moved.
For more background, see what the Big Five is and how trustworthy it really is.
Sources
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. — The foundational evidence for the maturity principle.
Roberts, B. W., et al. (2017). A systematic review of personality trait change through intervention. Psychological Bulletin, 143(2), 117–141. — Meta-analysis showing deliberate and clinical interventions can shift trait scores.
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. — Evidence that goal-directed effort can change traits.
Soto, C. J., & John, O. P. (2017). The next Big Five Inventory (BFI-2). Journal of Personality and Social Psychology, 113(1), 117–143. — On the structure and stability of Big Five traits.
Costa, P. T., & McCrae, R. R. (2008). The Revised NEO Personality Inventory (NEO-PI-R). In The SAGE Handbook of Personality Theory and Assessment. — Reference instrument for trait measurement and stability.
