For decades, personality has been treated as a personal blueprint. You may become more confident with experience, calmer after a difficult period, or better organised as work and family responsibilities grow.

Yet the underlying traits that shape how you think, feel and behave have often been seen as largely fixed by adulthood.

New research suggests that view is too rigid.

A large analysis published in Communications Psychology found that the Big Five personality traits change more across life than many people expect. In some comparisons, these shifts were similar to, or greater than, changes in self-esteem, income, physical health and life satisfaction.

The findings do not mean that people become entirely different every few years. Nor do they show that any person can deliberately remake their personality at will. Instead, they point to something more nuanced, personality is neither fixed in place nor endlessly flexible. It can change gradually, often unevenly, over decades.

The study focused on the Big Five, a widely used framework in personality psychology. These traits describe broad, relatively enduring patterns rather than momentary moods, clinical diagnoses, or moral qualities.

Extraversion reflects tendencies towards sociability and energy. Agreeableness relates to cooperation and concern for others. Conscientiousness includes organisation, diligence and responsibility. Neuroticism refers to a tendency towards negative emotional states, such as worry or emotional instability. Openness concerns curiosity, imagination and receptiveness to new ideas.

These traits are useful for describing differences between people. They do not define anyone completely.

Researchers first examined what the public believes about personality change. They surveyed 887 adults in the United States, asking participants to estimate how much 25 characteristics changed on average between the ages of 15 and 90. The list included the Big Five traits alongside factors such as income, socialising, physical health, self-esteem and life satisfaction.

Participants generally saw personality as among the least changeable aspects of life. This reflects a familiar cultural belief. Many people think of personality as a core self that remains much the same after adolescence, even if circumstances, routines and relationships change around it.

The researchers then tested that belief against long-term data.

They analysed eight large longitudinal data sets containing information from 166,971 people in the United States, Germany, Australia and the Netherlands. Longitudinal studies repeatedly assess the same people over time. This makes them especially valuable for examining change, because they can show how reported traits vary across years and across stages of life.

Using statistical models designed to distinguish age-related patterns from broader period and cohort effects, the researchers estimated personality change from age 15 to 90. They assessed two forms of change. Net change measured the overall difference between adolescence and older age. Cumulative change captured all movement along the way, including rises and falls that might not be visible in a simple beginning-to-end comparison.

That distinction matters.

A person could become less sociable during one stage of life, later regain some sociability, then finish in roughly the same position where they began. Looking only at the first and last measurement might make that person appear unchanged. Cumulative change captures the movement in between.

The results challenged the popular assumption that personality traits are almost permanent.

Across the data sets, the Big Five changed to a similar degree as several life variables that people usually regard as more flexible.

In certain comparisons, personality traits changed more. Conscientiousness, which includes being careful, dependable and organised, ranked fifth among 32 variables in total cumulative change. Extraversion and openness also ranked among the ten variables with the greatest overall life-span declines.

Those findings should be read as average patterns, not personal forecasts. They do not mean every older adult becomes less extraverted or less open, nor do they mean every person becomes more or less conscientious at the same rate. Individual lives vary greatly. Some people may show substantial change. Others may show little. Some will move in a different direction from the overall average.

Still, the central pattern was clear enough to expose a wide gap between public belief and observed change.

People underestimated personality change 90% of the time when considering year-to-year differences, according to the study’s comparison of perceived and measured change. Across the full life span, they underestimated it in every relevant comparison. Participants were more accurate when judging some other aspects of life, including changes in health.

This does not mean people are poor judges of their own character. It does suggest that many of us underestimate how much a person’s broad patterns of thinking, feeling and behaving can develop over time.

The idea of stable personality did not emerge from nowhere. Personality traits do show continuity. A person who is more conscientious than most of their peers at one age may remain relatively more conscientious than many peers later in life, even if their own level of conscientiousness changes. In other words, people can retain recognisable tendencies while still changing in meaningful ways.

That is an important distinction. Stability and change can coexist.

The new analysis adds perspective by placing personality alongside familiar markers of life change. Income can rise or fall. Health can improve or worsen. Satisfaction with life can shift with circumstances. Personality traits, often imagined as far more settled, may also move across the years in ways that are large enough to matter.

The research does not identify why these changes occur. It cannot show that a particular job, relationship, illness, bereavement, move, therapy programme or major life event caused a trait to change. The analysis is observational. It charts broad population patterns across time rather than testing a specific cause-and-effect pathway.

That caution is essential. It would be premature to conclude from this study that personality can be changed quickly through a course, an app, a workplace scheme, or a single period of self-improvement. The evidence supports the possibility of gradual personality development over a lifetime. It does not provide a simple formula for engineering it.

Even so, the findings may have practical value. A more flexible understanding of personality could help people resist limiting beliefs such as “I have always been this way, so I will always be this way.” It may also encourage greater patience with others. People are not blank slates, but neither are they frozen in adolescence.

For psychologists, educators and employers, the findings underline the need to avoid treating a single personality assessment as a permanent verdict. Such measures can be informative at a given point in time. They should not be used to make sweeping assumptions about someone’s future capabilities, relationships or potential for growth.

The study also highlights the value of long-term research. Short surveys can show what people are like at a particular moment. Repeated measures across years and decades show something different: lives unfold, circumstances change, and psychological characteristics can move with them.

The researchers noted a key limitation. Their analysis focused on average trajectories across large groups, not on the detailed paths of individual people. Population estimates are powerful, particularly with data from nearly 167,000 participants across four countries. Yet they cannot tell one person precisely how much they will change, when change may occur, or what might influence it.

Future research could combine large data sets with closer examination of individual lives. That may help scientists understand why some people change more than others, why traits rise at certain stages, and how social conditions, health, relationships and major transitions interact with personality development.

For now, the message is less dramatic than the myth it challenges, but more useful.

Personality is not a sealed container. It is also not endlessly remade by every new experience. Across the course of a life, the traits that shape everyday behaviour can change, sometimes more than we assume. Recognising that reality does not erase individuality. It simply makes room for growth, adaptation and the quiet fact that people can remain recognisably themselves while becoming different over time.