Yes. Personality traits can change during adulthood, not only behavior. Longitudinal research finds that average levels of several traits shift across adult life, and some people change more than others. At the same time, a new habit, role, or situation can alter what you do without producing an equally broad change in a trait. The most useful distinction is therefore not trait versus behavior as two sealed categories. It is level, time span, and context: a behavior is an observable act; a trait is a measured tendency across many situations; and a trait can gradually change as repeated experiences, goals, roles, and choices accumulate.
The short answer is both
Imagine someone who begins speaking more often in work meetings after taking on a coordinating role. The behavior has changed clearly. It would be premature to conclude that the person has become broadly more extraverted. The new role may reward preparation, make participation necessary, or provide more familiarity with the group. Those explanations can coexist with a slower change in social confidence or assertiveness.
A trait is best understood as a relatively broad tendency, not a permanent substance inside a person. Researchers usually estimate it from repeated or standardized descriptions of thoughts, feelings, and behavior. A single action is evidence about that moment. A pattern that persists across settings is stronger evidence about a trait. Even then, a trait score is an estimate, not a final identity statement.
Adult development research supports two ideas that sound opposed but are not. People often retain meaningful continuity in their relative differences from one another, while average trait levels and individual trajectories can still move. Stability tells us that change is not unlimited or random. Change tells us that adulthood is not a psychological freeze-frame.
What researchers mean by personality change
Several kinds of change are easy to confuse. Mean-level change asks whether a group tends to be higher or lower on a trait at a later age. Rank-order stability asks whether people who were relatively higher than others tend to remain relatively higher. Individual change asks whether a particular person moves, and by how much. These are different questions, so one answer cannot replace the others.
For example, a group might become more conscientious on average between early and middle adulthood. Many individuals may move in that direction, but some may remain similar and others may move in the opposite direction. Meanwhile, the people who were relatively more conscientious at the first measurement may still tend to be relatively more conscientious later. Average development and personal continuity can therefore appear in the same data.
Longitudinal research, which measures the same people at more than one point, is especially useful here. It is not perfect: repeated self-reports, changing circumstances, sample loss, and the wording of an instrument can affect results. Cross-sectional age comparisons also risk confusing age with generation. A careful conclusion should describe the pattern and its limits rather than promise a fixed timetable for everyone.
The broad pattern across adulthood
A widely cited meta-analysis of 92 longitudinal samples found changes in several trait categories across the life course. It reported increases in social dominance, conscientiousness, and emotional stability, especially in young adulthood, while social vitality and openness showed different age-linked patterns and agreeableness changed later in life. The finding is not that every adult follows one curve. It is that trait development continues after adolescence and that different parts of personality can move differently.
A later study that examined both broad Big Five domains and narrower facets reached an important refinement. Agreeableness and conscientiousness tended to increase in its adult samples, but individual facets within a domain did not always follow the same path. Industriousness, for example, need not develop in exactly the same way as orderliness. A broad label can hide the smaller pattern that matters in daily life.
This is why statements such as ‘adults become more conscientious’ should be treated as population-level summaries, not predictions about a particular reader. Age, culture, opportunity, health, work, relationships, and measurement choices can all shape the observed pattern. The evidence supports plasticity with continuity, not a universal script.
Why a facet can change before a whole trait
Broad traits are bundles of related but distinguishable tendencies. Conscientiousness can include persistence, organization, and impulse control. Extraversion can include social energy, positive emotion, and assertiveness. Someone may become more comfortable initiating a difficult conversation while remaining quiet in large social gatherings. Calling that a complete change in extraversion would lose useful detail.
Facet-level thinking gives self-reflection a more observable target. Instead of asking, ‘Am I a different person now?’, ask, ‘Which part of this pattern has shifted, and where?’ Look for repeated evidence: starting tasks without a deadline, finishing routine obligations, asking for clarification, sharing an opinion, or recovering after criticism. These are not interchangeable signs, and none alone proves a trait change.
Soto and John’s study found substantial individual differences in adult change and reported that different facets within the same broad domain could show different age trends. Its longitudinal sample was relatively small and demographically narrow, so it should not be treated as a complete map of adulthood. Its practical lesson is stronger than a simple label: examine the narrower behavior or tendency before making a broad claim.
Behavior can change without a broad trait shift
Behavior is shaped by more than personality. Rules, incentives, skills, fatigue, social expectations, resources, and the people present can all change what someone does. A person who rarely speaks in an unfamiliar group may lead a familiar team meeting because the task, role, and knowledge are different. Neither observation alone settles whether the person is introverted, anxious, cautious, prepared, or simply conserving attention.
A useful comparison is to record the same behavior across settings. Note what happened, who was present, what was at stake, how familiar the task was, and what happened afterward. If the pattern appears only under one set of conditions, a context explanation deserves serious weight. If it appears across different settings and persists after the conditions change, a broader trait interpretation becomes more plausible, though still provisional.
The reverse also happens. A person may report feeling more patient or organized while their visible behavior changes only gradually. Intentions, skills, and opportunities do not always move together. Treat behavior as evidence to examine, not as a transparent window into a hidden trait.
Life events may contribute, but they are not automatic causes
New roles and transitions can provide repeated practice in a different way of acting. A first job may require planning and follow-through. Caring for another person may change how time and responsibility are organized. A move may create more chances for social exploration or more reasons to protect privacy. Over time, recurring demands can become part of a person’s usual repertoire.
A systematic review and meta-analysis of prospective studies examined events such as starting a relationship, marriage, parenthood, separation, graduation, a first job, unemployment, and retirement alongside personality characteristics. This kind of design is stronger than asking people to remember whether an event changed them, because it includes measurements before and after the event. It still cannot make every association a simple cause. People choose, anticipate, and interpret events, and those prior differences can affect both the event and later change.
The careful conclusion is that life events can be part of personality development, with effects that depend on the event, the person, and the surrounding conditions. ‘This experience changed me’ may be a reasonable personal interpretation. ‘This event changes everyone in the same way’ is a much stronger claim than the evidence supports.
Can deliberate practice change a trait?
Some research has examined volitional personality change, meaning self-directed change toward a personal goal. A 2024 systematic review identified 30 longitudinal studies with 7,719 participants. It found that merely wanting to change was only weakly related to later trait change, while interventions designed to support change showed promising but still limited effects. The authors explicitly called for more research on generalizability and mechanisms.
This distinction matters for everyday advice. A goal such as ‘be more confident’ is too broad to test. A behavioral plan is clearer: ask one question in each weekly meeting, then record whether the action felt easier, whether it occurred in other settings, and whether the pattern lasted after the plan ended. Repeated behavior may build skills and alter how a person experiences a situation. It does not guarantee a global trait transformation.
The evidence also cautions against treating personality as a project that must be optimized. Change can be useful when it serves a chosen value or practical need. It is less useful when a person tries to erase every uncomfortable tendency or uses a label to judge their worth. The aim is a more accurate description of options, not a perfect personality.
A practical way to tell what is changing
When you notice a difference, separate three questions. First, what observable behavior is different? Second, which trait or facet might that behavior resemble? Third, what competing explanation fits the same evidence? This prevents one striking example from becoming an identity verdict.
Use a small comparison across at least three settings, such as work, close relationships, and an unfamiliar group. For each setting, record the behavior, the situation, the time span, and the consequence. Then ask whether the change is stable across contexts, linked to one role, or still dependent on support and structure. A pattern that broadens and persists is more informative than a short burst during a transition.
You can also compare your current description with older records, messages, or decisions, while remembering that memory and self-presentation are imperfect. If another person’s observation is relevant, ask for a specific example rather than a label. ‘You seem more willing to disagree in meetings’ is testable. ‘You have become a completely different person’ is not.
What to take from the evidence
Personality traits are neither fixed for life nor infinitely malleable. Adult research supports gradual change, meaningful continuity, and substantial differences between people’s paths. Broad traits can shift, narrower facets can move in different directions, and behavior can change because a context changed before any broad trait did.
For careful self-understanding, use trait language as a working summary of repeated patterns. Keep the summary open to new evidence. If your behavior has changed, first describe the change plainly. Then check whether it travels across settings and time. Finally, decide whether you want to maintain it, test it in another context, or adjust the environment that made it possible.
Start with one behavior you want to understand. Observe it in three settings for two weeks, write down the conditions that surround it, and compare the pattern rather than a single day. If the evidence stays narrow, describe a context-specific change. If it becomes broader and steadier, consider whether a trait or facet description now adds useful information. Explore more evidence-aware personality explainers in the [personality profile topics library](/topics).
Sources and notes
- Personality Trait Change in Adulthood
Supports the conclusion that personality-trait development occurs across adult age periods and that life and work experiences are associated with change.
- Patterns of Mean-Level Change in Personality Traits Across the Life Course
Summarizes a longitudinal meta-analysis finding age-linked change in several personality trait categories across the life course.
- Life Events and Personality Change: A Systematic Review and Meta-Analysis
Supports the careful discussion of prospective studies linking specified life events with later personality characteristics.
- Toward a Theory of Lifespan Personality Trait Development
Provides an authoritative review of lifespan personality-trait development and the field’s theoretical limits.
- Development of Big Five Domains and Facets in Adulthood
Supports the distinction between broad domains and facets, including different age trends and individual differences in change.
- A Systematic Review of Volitional Personality Change Research
Supports the qualified account of self-directed personality change, including limited evidence for goals alone and more promising intervention findings.
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