Can personality change? What is inherited, what shifts with age, and what you can change

To answer “can personality change?” you need a way to measure personality. A framework widely used in personality research is the Big Five: openness to new experiences, conscientiousness in planning and following through, extraversion, drawing energy from people and activity, agreeableness in cooperating and caring, and emotional sensitivity, how strongly you feel emotions such as anxiety and worry (often called neuroticism).

The Big Five does not sort people into a few types. It scores how much of each of the five tendencies a person has, on a continuum. So personality change is less a sudden jump to another type and more a gradual rise or fall in the score of some tendency.

Drawing on research, this guide looks at three things: how much is inherited, how personality shifts with age and experience, and what helps when you want to change. You can check your own five scores with the Big Five personality test.

A meta-analysis that pooled 62 independent effect sizes from twin and family studies, more than 100,000 participants in all, estimated that about 40% of individual differences in personality are due to genetic influences and about 60% to environmental ones (Vukasović and Bratko, 2015). The share did not differ much by personality model or gender, but it did by study design: estimates were about 47% in twin studies and about 22% in family and adoption studies.

One caution matters here. The 40% does not mean that 40% of a given person’s personality is fixed. It is a population-level estimate of how much of the variation between people is explained by genetic differences. On its own, the number says nothing about whether personality can change within one person.

The remaining share includes the effects of experiences that differ from person to person, along with measurement error. Genes explain part of the differences in personality, but not all of them.

A meta-analysis of 92 samples from studies that followed the same people over time found that, on average, people become more conscientious and more emotionally stable, that is, lower in emotional sensitivity, as they age. Social dominance, one facet of extraversion, also rose, and these changes were most marked between ages 20 and 40 (Roberts, Walton and Viechtbauer, 2006).

Not every tendency moved the same way. Openness and social vitality, another facet of extraversion, rose in adolescence and fell in old age, and agreeableness showed clear change only in old age. In middle and old age, four of the six trait categories still changed significantly (Roberts, Walton and Viechtbauer, 2006).

These are average trends, so not everyone changes this way. They do show, though, that personality keeps moving well into adulthood, contrary to the idea that the personality you have at 20 is the one you keep for life.

A meta-analysis of 207 studies that tracked personality scores during interventions, mostly clinical ones such as psychotherapy, found marked changes in personality scores over an average of 24 weeks. The largest shift was toward being less emotionally reactive, that is, lower emotional sensitivity, followed by extraversion (Roberts, Luo, Briley, Chow, Su and Hill, 2017).

The changes appeared in both experimental and non-experimental designs, showed up in non-clinical interventions too, and held in follow-ups after the intervention ended. The type of therapy was not strongly related to how much change occurred (Roberts, Luo, Briley, Chow, Su and Hill, 2017).

So getting help for anxiety or low mood may do more than ease symptoms; it can be a chance to shift long-standing ways of reacting emotionally. If worry or low mood is shaking your daily life, the anxiety check-in (GAD-7) or the depression check-in (PHQ-9) can help you see where you are before you talk to a professional. These check-ins are not diagnoses.

Many people want to change some part of their personality. In two experiments that tracked participants closely for 16 weeks, people who said at the start that they wanted to increase a Big Five trait tended to report increases in that trait, and in trait-relevant daily behavior, over the following 16 weeks (Hudson and Fraley, 2015).

The same research tested two interventions. One did not work; the other, which trained participants to form specific implementation intentions, helped them reach the changes they wanted (Hudson and Fraley, 2015). An implementation intention replaces a vague goal like “be more outgoing” with a plan for when and what, such as “at lunch on Monday, I will ask one colleague to eat with me” (an example of the format, not a sentence from the study).

By trait, that might look like this: to raise conscientiousness, “at 10 p.m., I write down three things to do tomorrow”; to lower emotional sensitivity, “when a worry starts, I take three long breaths and write the worry down in one sentence.” Note, though, that the study mainly measured self-reported scores, so whether changed behavior looks just as different to others is still an open question.

Change matters because personality is linked to many life outcomes. A review of long-term prospective studies found that personality traits were related to mortality, divorce and occupational attainment about as strongly as socioeconomic status and cognitive ability were (Roberts, Kuncel, Shiner, Caspi and Goldberg, 2007).

A large replication project checked whether such links hold up. When 78 previously reported links between personality and life outcomes were retested in preregistered studies, 87% were statistically significant again in the expected direction, although the effects were about 77% as strong as in the original studies (Soto, 2019).

These are group-level tendencies, so your scores do not decide your future. Whether changing personality also changes these outcomes has rarely been tested directly. Still, the fact that personality is linked to life and can also change is a reason to consider gradual effort in the direction you want.

Q. At what age does personality set? A. There is no set age. Average change was especially large between 20 and 40, but several traits kept changing in middle and old age (Roberts, Walton and Viechtbauer, 2006). It may be more accurate to say that the direction and size of change shift with age than that personality sets.

Q. Can an introvert become more extraverted? A. To some degree, if you want to. In one study, people who said they wanted to raise their extraversion showed self-reported increases in their scores and daily behavior over 16 weeks (Hudson and Fraley, 2015). Introversion is not a flaw to fix, though, so whether to change is up to the life you want. For how introversion differs from high sensitivity (HSP), see HSP vs introvert.

Q. Can my MBTI type change? A. MBTI splits each tendency into two sides and reports a type, so people near a boundary can see a letter flip with a small change or with how they feel that day. Why results keep changing is covered in MBTI accuracy, and how the two tests differ in MBTI vs Big Five.

Q. Do I need counseling to change my personality? A. Not necessarily. One study found self-reported change from setting your own goals and implementation plans (Hudson and Fraley, 2015). If anxiety or low mood is shaking your daily life, though, counseling can help shift even the way you react emotionally.

References: Vukasović & Bratko (2015), Psychological Bulletin 141(4), 769-785, https://doi.org/10.1037/bul0000017; Roberts, Walton & Viechtbauer (2006), Psychological Bulletin 132(1), 1-25, https://doi.org/10.1037/0033-2909.132.1.1; Roberts, Luo, Briley, Chow, Su & Hill (2017), Psychological Bulletin 143(2), 117-141, https://doi.org/10.1037/bul0000088; Hudson & Fraley (2015), Journal of Personality and Social Psychology 109(3), 490-507, https://doi.org/10.1037/pspp0000021; Roberts, Kuncel, Shiner, Caspi & Goldberg (2007), Perspectives on Psychological Science 2(4), 313-345, https://doi.org/10.1111/j.1745-6916.2007.00047.x; Soto (2019), Psychological Science 30(5), 711-727, https://doi.org/10.1177/0956797619831612.