Can Your Personality Change Over Time? What Science Says About Trait Stability and Growth
Yes, your personality can change over time — but not in the dramatic, overnight transformation that popular psychology often promises. Decades of longitudinal research show that personality traits, the characteristic patterns of thinking, feeling, and behaving that define who you are, display both meaningful stability and gradual change across the lifespan. A 2026 meta-analysis by Haehner and colleagues, published in Psychological Bulletin and drawing on 362 longitudinal studies with nearly 400,000 participants, confirmed that personality trait variance remains remarkably stable across age groups — yet mean-level shifts in specific traits continue well into your sixties and seventies. Research by Brent Roberts at the University of Illinois found that personality traits typically show correlation coefficients of around 0.6 to 0.7 over periods of several years, meaning roughly 50 to 60 percent of personality variance stays stable while a substantial portion remains open to change. In other words, your core personality is neither set in stone nor infinitely malleable — it is a stable foundation that gradually evolves as you move through life.
The most thoroughly validated framework for tracking these changes is the Big Five personality model, also called the Five Factor Model or OCEAN: Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism. Each dimension represents a spectrum rather than a category, which makes the Big Five far better suited for measuring gradual change than type-based systems like the Myers-Briggs Type Indicator (MBTI), which sorts people into one of 16 personality types. If you want to see where you currently stand on these dimensions, tools like personalitree.com offer free Big Five and 16-type personality tests that take about ten minutes — a practical baseline you can revisit years later to observe whether and how your profile has shifted.
What Does "Personality Stability" Actually Mean?
Personality stability refers to how consistently your trait levels hold over time, but researchers distinguish between two very different kinds of stability that often pull in opposite directions. Rank-order stability, also called differential continuity, measures whether you maintain your relative position compared to other people — if you are more conscientious than average at 25, are you still more conscientious than average at 45? Mean-level change, by contrast, measures whether the average scores for an entire group rise or fall over time — whether everyone becomes more agreeable as they age, for instance.
A group can show strong rank-order stability — people keep their relative positions — while simultaneously showing significant mean-level change — everyone drifts upward on a trait together. Understanding this distinction matters because it explains why you can feel like a completely different person at 40 than at 20, even though you still rank similarly compared to your peers. Both types of stability are relevant when asking whether personality can change, and both have been studied extensively through longitudinal designs that track the same individuals over years or decades.
The "Plaster Hypothesis": Why Scientists Once Thought Personality Was Fixed
In the 1990s, researchers Paul Costa and Robert McCrae proposed what became known as the "plaster hypothesis" — the idea that personality traits crystallize by around age 30 and change very little afterward. Their data from the Baltimore Longitudinal Study of Aging showed high test-retest correlations for Big Five traits across decades of adulthood, suggesting remarkable stability.
A 2010 study by Antonio Terracciano, McCrae, and Costa themselves, published in the Journal of Research in Personality, added important nuance. Using 684 participants assessed three times over several years, they found that intra-individual personality stability increases up to age 30 and then plateaus — but a plateau is not a flatline. They found that 92 percent of participants had stability coefficients above 0.50, meaning most people retained much of their personality, but the remaining variance still allowed for meaningful individual change. A subsequent meta-analysis by Roberts, Walton, and Viechtbauer (2006), published in Psychological Bulletin, analyzed 92 longitudinal studies and demonstrated systematic mean-level changes well beyond age 30, directly challenging the idea that personality hardens permanently in early adulthood.
How Each Big Five Trait Changes With Age
Research consistently identifies predictable patterns of mean-level personality change across adulthood, a phenomenon sometimes called the "maturity principle" — the tendency for people to become more socially adapted over time. The specific direction and magnitude of change varies by trait:
- Conscientiousness — the tendency toward self-discipline, organization, and goal-directed behavior — rises steadily, with the steepest gains between ages 20 and 40, then continues more gradually into the sixties.
- Agreeableness — warmth, cooperation, and concern for others — grows particularly in middle age and beyond, as people invest in deeper relationships and take on mentoring or caregiving roles.
- Neuroticism — the tendency toward anxiety, irritability, and emotional volatility — generally declines, meaning people become more emotionally stable as they mature. The sharpest drops occur during young adulthood.
- Extraversion — sociability and assertiveness — shows a mixed pattern: social dominance tends to increase while excitement-seeking tends to decrease with age.
- Openness to Experience — curiosity and receptiveness to new ideas — remains relatively stable through most of adulthood but may decline slightly in very late life.
The 2026 meta-analysis by Haehner and colleagues also found that neuroticism variance increases during late childhood and early adolescence (ages 5 to 14), suggesting that the teenage years represent a period of heightened emotional differentiation before gradual stabilization begins. They also found that extraversion variance decreases during middle and late adulthood (ages 45 to 80), suggesting people become more similar to one another on this dimension as they get older. These findings mean that personality change is not uniform across traits or across life stages — some dimensions shift more than others, and the timing of change varies considerably.
Can You Intentionally Change Your Personality?
Research suggests that intentional, self-directed personality change is possible, though it requires sustained effort rather than wishful thinking. Several Big Five traits — including extraversion, conscientiousness, and agreeableness — have been shown to respond to volitional change interventions. Even relatively short programs, such as a two-week smartphone-based intervention targeting a specific facet like self-discipline, can produce measurable shifts, at least in the short term.
Therapy also drives personality change. A common question people ask is whether counseling can actually shift their personality. Evidence indicates that psychotherapy, particularly cognitive behavioral therapy, can reduce neuroticism over months of treatment, and these changes tend to be durable rather than temporary. The key finding across studies is that consistency matters more than intensity — small, regular behavioral changes accumulate into trait-level shifts over time, while sporadic intense efforts rarely produce lasting change. This aligns with what personality researchers describe as the cumulative continuity principle: repeated experiences and behaviors gradually reshape the habitual patterns that define your trait profile.
What Life Events Do to Your Personality
Major life transitions — marriage, becoming a parent, career changes, trauma, or retirement — can catalyze measurable personality shifts. Research published by Bleidorn, Hopwood, and Lucas in the Journal of Personality (2018) found that first long-term relationships are associated with decreases in neuroticism, while marriage can initially lower agreeableness before it stabilizes over time. Taking on a leadership role at work can gradually increase assertiveness, even in someone who starts out shy. These shifts are not random — they reflect the ways that sustained social roles reshape habitual patterns of thinking and behaving, a process consistent with the concept of character traits as malleable dispositions shaped by ongoing experience.
What This Means for Personality Testing
If personality can change, what is the point of taking a personality test? A personality assessment captures a snapshot of your current trait levels, which remains genuinely useful for self-awareness, career planning, and understanding your relational tendencies at this moment in time. It does not lock you into a fixed identity. Retaking a Big Five test every few years can reveal whether you are following the typical developmental trajectory — rising conscientiousness, declining neuroticism — or charting your own course shaped by unique experiences. Websites like personalitree.com make this kind of longitudinal self-tracking accessible, offering both the Five Factor Model and 16-type frameworks in a format that takes about ten minutes to complete.
It is worth noting that the popular MBTI — which categorizes people into one of 16 personality types like INTJ or ENFP — is less well-suited for tracking change because its binary categories (introvert versus extrovert, thinking versus feeling) do not capture gradual shifts. A person who moves from the 40th to the 60th percentile on extraversion has changed meaningfully, but the MBTI would still label them an introvert. The Big Five's dimensional approach provides far more sensitivity to the kinds of gradual, cumulative changes that research consistently documents across the lifespan.
Frequently Asked Questions
Can your personality type change over time?
Yes. While your broad personality structure shows considerable stability — correlation coefficients of 0.6 to 0.7 over several years — research consistently documents mean-level shifts in Big Five traits across the lifespan. Conscientiousness and Agreeableness tend to rise, Neuroticism tends to fall, and these changes continue well beyond age 30. Type-based labels like MBTI categories are less sensitive to these gradual shifts because they use binary cutoffs rather than continuous dimensions.
At what age does personality become stable?
Research by Terracciano, McCrae, and Costa (2010) found that intra-individual personality stability increases up to about age 30 and then plateaus. However, a plateau means the rate of change slows — it does not mean change stops entirely. Meta-analyses show that mean-level personality change continues through middle age and into the sixties and seventies, with traits like Conscientiousness still rising gradually even in older adults.
Can therapy change your personality traits?
Evidence suggests yes. Psychotherapy, particularly cognitive behavioral therapy, has been shown to reduce neuroticism over months of treatment. The personality changes associated with therapy tend to be durable rather than temporary, and they reflect genuine shifts in how people habitually process emotions and respond to stress, not just symptom management. Consistency in therapeutic practice appears to be the strongest predictor of lasting trait change.
How much of personality is genetic versus shaped by experience?
Twin studies and behavioral genetics research estimate that approximately 40 to 60 percent of personality variation is attributable to genetic factors. The remaining variation reflects environmental influences, life experiences, social roles, and intentional change efforts. This means genetics set a range rather than a fixed point — your experiences and choices determine where within that range you ultimately land.
Should I retake a personality test if I took one years ago?
Retaking a personality test after several years can be informative, especially if you use a dimensional framework like the Big Five rather than a categorical system. You may find that your trait levels have shifted in ways that align with typical developmental patterns — higher Conscientiousness, lower Neuroticism — or you may discover unique changes driven by your own life experiences. Either way, comparing results over time offers a richer picture of personal growth and self-awareness than a single snapshot ever could.