Most adults believe their core personality stays the same, but new research shows our traits can shift as much as our health or income—sometimes without us noticing
Most Americans like to believe they remain fundamentally the same person throughout life, even as circumstances change. But new research from the University of Zurich and the University of Texas challenges that assumption, revealing that our core personality traits are far more flexible than we realize—sometimes shifting as much as our physical health or financial situation.
Researchers surveyed nearly 900 adults about how much they thought their personality would change from adolescence to old age. Then, they analyzed data from eight major longitudinal studies, tracking almost 167,000 people in the U.S., Germany, Australia, and the Netherlands over decades. The results were clear: people consistently underestimated how much their personality would actually change, both year to year and across the lifespan.
Many assume that once childhood and the teenage years are over, personality is set in stone. Phrases like “just be yourself” reinforce the idea of a fixed inner core. But the data tells a different story. The five major personality traits—extraversion, agreeableness, conscientiousness, neuroticism, and openness—continue to evolve well into adulthood and even late life. In fact, these traits can shift as much as, or more than, factors like income, health, or life satisfaction.
Misjudging Change
To test perceptions, participants rated how much they thought 25 different characteristics—including the five big personality traits, income, health, self-esteem, and social activity—would change between ages 15 and 90. Across the board, people underestimated the degree of change in personality traits. The gap between belief and reality was especially wide for traits like conscientiousness and openness, which showed significant shifts over time in the longitudinal data.
When researchers compared these beliefs to actual long-term data, the contrast was striking. Personality traits changed as much as, or more than, many life factors people assume are more volatile. For example, conscientiousness—the tendency to be organized, responsible, and careful—looked very different at 15 than at 90. Extraversion and openness also declined more than most participants expected. Yet these changes rarely felt dramatic to the individuals themselves. Instead, people often interpreted new behaviors as revealing a side of themselves that was always there, rather than as a true shift in personality.
Gradual Evolution
These findings don’t mean people become unrecognizable overnight. Personality change is usually gradual, unfolding over years. The research describes average trends across large groups, not precise predictions for any one person. Still, the difference between how much we think we change and how much we actually do is significant—and has real implications for self-understanding, relationships, and even therapy.
According to Communications Psychology, the study’s authors emphasize that while personality isn’t endlessly malleable, it’s far from fixed. The five big traits remain flexible enough to shift in meaningful ways, even after we reach adulthood. This challenges the popular belief that our character is set for life and suggests that personal growth and adaptation are possible at any age.
Understanding that personality can evolve may help explain why some people thrive after major life changes, while others struggle. It also raises questions about how we support each other through transitions. As discussed in coverage of genuine kindness and stress, the way we relate to ourselves and others can have a profound impact on well-being—especially if we recognize that change is not only possible, but likely.
Recent national surveys show that nearly 60% of Americans believe their personality is mostly set by age 30. Yet, longitudinal studies tracking individuals for decades reveal measurable shifts in traits like conscientiousness and openness well into the 70s and beyond. These findings suggest that the capacity for personal change is much greater than most people assume, with implications for mental health, relationships, and even career development.
The "Big Five" personality traits—extraversion, agreeableness, conscientiousness, neuroticism, and openness—are widely used by psychologists to describe the broad patterns of how people think, feel, and behave. While these traits are relatively stable compared to fleeting moods or habits, they are not immune to life’s pressures, transitions, or opportunities. Research shows that targeted interventions, such as cognitive-behavioral therapy or structured life coaching, can sometimes foster positive shifts in these traits, especially when combined with sustained effort and supportive environments.
