Can your personality change?

Yes, your personality can change, usually gradually and usually within limits. Long-term studies show that average trait levels shift across adulthood, and experiments suggest that some people can nudge their traits on purpose. You are unlikely to become a different person, but you are not stuck either.

That middle ground is what the research supports. It is also more useful than either "people never change" or "you can be anything if you try".

What changes on its own as you get older

The largest summary here is a meta-analysis by Brent Roberts, Kate Walton and Wolfgang Viechtbauer, drawing on 92 samples followed over time. They looked at how average levels of traits move across the life course.

They found that people tend to increase in social dominance (one part of extraversion), conscientiousness and emotional stability, especially between about 20 and 40. Social vitality (another part of extraversion) and openness tend to rise in adolescence, then fall in old age. Agreeableness changed only in old age.

Two things are worth keeping in mind:

• Change did not stop at 30. Four of the six trait categories they tracked showed significant change in middle and old age.
• These are averages. They describe the general drift of big groups, not what will happen to you. A trend across thousands of people can't tell you what your 40s will be like.

The takeaway is a hopeful one. Many people grow a little steadier and more organised with time, without any special plan.

Can you change your personality on purpose?

This is what most people really want to know. Nathan Hudson and Chris Fraley tested it directly, in two 16-week randomised experiments. People who set a goal to increase a Big Five trait tended to report actual increases in that trait over the following weeks, along with more of the matching daily behaviour.

The experiments also tested two ways of helping. One did not work. The other taught people to write implementation intentions, which are specific if-then plans such as "if I walk into the office kitchen, then I will start a conversation". That approach did help people move towards the change they wanted.

A couple of honest caveats apply. The main results are based on people's own reports, and the authors describe the work as a first step. Wanting to change can also shape how you see yourself. Even so, the daily behaviour measures point the same way, and that is encouraging.

What about structured support?

Roberts and colleagues also carried out a systematic review of 207 studies tracking trait measures during interventions, with a main focus on clinical settings. Over an average of 24 weeks, trait measures shifted noticeably, and the changes held up in the longer-term follow-ups they could examine. Emotional stability showed the most change, followed by extraversion.

Since most of those studies came from therapy settings, it would be a stretch to expect the same from a self-help plan. What the review does show is that traits are more responsive than people once assumed.

Traits are averages, not cages

Part of the reason change is possible is that a trait is a tendency, not a fixed setting. William Fleeson and Patrick Gallagher ran 15 experience-sampling studies, with more than 20,000 reports of how people were actually behaving in the moment. Trait scores did strongly predict people's typical behaviour, with correlations between .42 and .56.

That means your traits really do describe you, and it also leaves room for variety. You can have a clear usual pattern and still act out of character when the situation calls for it. A quiet person can give a great speech. An easygoing person can hold a firm line. You have probably done something like this more often than you think.

How to try it, if you want to

You don't have to change anything. Most traits come with strengths at both ends, and plenty of people are better served by working with their tendencies than against them. But if there is something you would like to shift, the evidence points to a practical approach:

1. Pick one behaviour, not one trait. "Be more organised" is vague. "Write tomorrow's top three tasks before I close my laptop" can be done today.
2. Write an if-then plan. Tie the new action to a clear cue.
3. Give it weeks, not days. The experiments ran for months, not a long weekend.
4. Check against more than your own opinion. A person who sees you often may notice changes before you do, or tell you kindly that they haven't noticed yet. Our article on how accurately people rate themselves explains why this matters.

Measure now, compare later

It is hard to notice slow change without a starting point. Take the Core Personality Expedition to put a marker down. It is free to take with no sign-up, and it uses public-domain IPIP items based on the Big-Five Factor Markers. If you want to see whether other people notice what you are working on, Second Sight lets them rate you anonymously, averaged with at least two others.