The Question Nobody Asks Until They Take a Second Personality Test
Most people who take a personality test treat the results as a fixed label. You score high in Openness, moderate in Extraversion, and low in Neuroticism — and you file that away as a permanent description of who you are. But then something happens. A few years pass, maybe a decade, and you take the test again. The scores shift. Not dramatically, but noticeably. Openness drops a few points. Conscientiousness climbs. You start to wonder: was the first test wrong, or did you actually change?
Personality psychology has been wrestling with this question for nearly a century. The answer that has emerged from decades of longitudinal research is neither as simple as “people never change” nor as optimistic as “you can become anyone.” The truth sits in between — and understanding it has practical implications for how you think about personal growth, therapy, relationships, and the trajectory of your life.
The Evidence for Stability: Why Personality Feels Permanent
There is a reason personality tests feel revealing rather than random. Research consistently shows that personality traits are remarkably stable over time, especially in adulthood. Large-scale longitudinal studies — including the Dunedin Study in New Zealand, which tracked over 1,000 people from birth to midlife, and the Baltimore Longitudinal Study of Aging, spanning decades — have found that rank-order stability for Big Five traits ranges from 0.70 to 0.85 over ten-year periods in adults.
What does that number mean in practice? If you are the most conscientious person in your friend group at age 30, there is a very good chance you will still rank among the most conscientious at age 50. Your absolute score might shift, but your position relative to others tends to hold. This stability is one of the reasons personality researchers consider the Big Five a robust framework — the traits are not fleeting moods or situational states. They reflect enduring patterns in how a person thinks, feels, and behaves across contexts.
The biological foundations of personality contribute to this stability. Behavioral genetics research, including genome-wide association studies, consistently estimates that 40 to 60 percent of the variance in Big Five traits is heritable. Twin studies, adoption studies, and molecular genetics all converge on the conclusion that your genetic makeup sets a range for each trait — a baseline that predisposes you toward certain patterns. This is why personality can feel so deeply ingrained. To some extent, it is built into your biology.
The Maturity Principle: The Predictable Arc of Personality Change
Here is where it gets interesting. Despite the strong stability findings, personality does change — and the changes follow a surprisingly consistent pattern across populations. Personality psychologists Robert Roberts and Daniel Mroczek have documented what they call the “maturity principle”: as people move through adulthood, they tend to become more emotionally stable, more agreeable, and more conscientious, while Extraversion and Openness tend to decline modestly.
The pattern looks roughly like this:
- Neuroticism decreases — people generally become less emotionally reactive and less prone to anxiety and negative mood swings as they age, with the steepest declines occurring between age 20 and 40.
- Agreeableness increases — most adults become more cooperative, trusting, and warm over time, particularly during their 30s and 40s.
- Conscientiousness increases — responsibility, organization, and self-discipline tend to rise through midlife, plateauing around age 50 to 60.
- Extraversion decreases slightly — social energy and sensation-seeking tend to decline modestly, though the change is smaller than for the other three traits.
- Openness to Experience decreases — receptivity to novelty and unconventional ideas tends to decline gradually, especially after age 60.
These are population averages, not individual mandates. Some people become less conscientious with age. Some become more extraverted. But the aggregate trend is reliable enough to show up in studies across cultures, including research from the United States, Germany, Japan, and the Netherlands. The maturity principle is one of the most robust findings in personality development research.
What Drives These Changes
The maturity principle raises an obvious question: why does personality follow this arc? Researchers point to several interacting mechanisms.
Biological maturation. The prefrontal cortex, which governs impulse control, planning, and emotional regulation, continues developing well into a person’s mid-20s. As brain maturation progresses, the neurological capacity for conscientious behavior and emotional stability literally expands. Hormonal changes across the lifespan — from the testosterone and cortisol shifts of early adulthood to the slower endocrine changes of later life — also influence trait expression.
Role investment. The most widely supported explanation for personality change is that people invest in social roles that reward certain traits. When you take on a job that requires discipline, a marriage that demands compromise, or a parenting role that necessitates patience, you practice those behaviors repeatedly. Over years, the practice reshapes your habitual responses. A disorganized 22-year-old who becomes a project manager at 32 is not faking their newfound organization — they have built genuine conscientiousness through sustained role demands.
Life experiences. Major events — career changes, relocation, bereavement, serious illness, becoming a parent — can catalyze personality shifts. Research on post-traumatic growth has found that some people who experience significant adversity report lasting increases in Agreeableness and appreciation for life, though the effects vary considerably by individual and circumstance. Positive experiences matter too. Studies have found that people who enter satisfying romantic relationships show decreases in Neuroticism that persist over time, even after controlling for baseline differences.
Can You Change Your Personality on Purpose?
This is where the research gets particularly interesting — and directly relevant to anyone who has ever wanted to become more outgoing, less anxious, or more organized. A growing body of evidence suggests that intentional, volitional personality change is not only possible but achievable through sustained effort.
Pioneering work by Nathan Hudson and Christopher Fraley at the University of Illinois demonstrated that people who set specific goals to change a particular personality trait — and who followed up with behavioral strategies over a 16-week period — showed measurable changes in their Big Five scores compared to control groups. The changes were not enormous, but they were statistically significant and persisted at follow-up assessments.
The strategies that worked in these studies were surprisingly practical:
- Goal setting and behavioral challenges. A person trying to increase Extraversion might commit to initiating one conversation with a stranger per day. Someone working on Conscientiousness might adopt a daily planning routine. The key was consistency — small, repeated behaviors that gradually reshaped habitual patterns.
- Environmental restructuring. Changing your circumstances to support the trait you want to develop. Wanting to become more open to experience? Deliberately seeking out unfamiliar environments, reading outside your usual genres, spending time with people who challenge your assumptions.
- Situational cue modification. Identifying the situations that trigger unwanted trait expressions and adjusting your exposure to them. A person trying to reduce Neuroticism-driven rumination might limit late-night social media scrolling, which research consistently links to mood destabilization.
The research does not suggest that personality is infinitely malleable. A deeply introverted person is unlikely to transform into a natural social butterfly through willpower alone. But moderate, meaningful shifts — moving from the low end to the middle of a trait distribution, for instance — appear to be within reach for people who commit to sustained behavioral change.
Hudson’s subsequent research has also found that some traits are easier to change intentionally than others. Emotional Stability (the low-Neuroticism end of the spectrum) and Conscientiousness tend to respond well to intentional intervention, while Extraversion and Agreeableness show more resistance. Openness, perhaps unsurprisingly, sits in the middle — people can become more open through deliberate exposure to new experiences, but the changes tend to be modest.
The Role of Therapy and Intervention
Clinical psychology provides another window into personality change. A meta-analysis published in Psychological Bulletin examining data from over 144 studies found that psychotherapy can produce meaningful changes in personality traits, particularly Neuroticism and Extraversion. Patients entering therapy for depression or anxiety often show reductions in Neuroticism that exceed the typical annual rate of natural change. The effects are not limited to clinical populations — even people in therapy for personal growth rather than diagnosable conditions show personality shifts.
Cognitive Behavioral Therapy appears especially effective at reducing Neuroticism, likely because it directly targets the negative thought patterns and catastrophic thinking that define the high-Neuroticism profile. Mindfulness-based interventions have shown promise for both Neuroticism reduction and increases in self-reported Conscientiousness, possibly through the attentional discipline that regular mindfulness practice requires.
The practical implication is that personality change is not limited to the slow, natural drift of the maturity principle. Focused psychological intervention can accelerate shifts that might otherwise take years to occur — or shift traits in directions that natural maturation would not produce on its own.
What This Means for Your Personality Test Results
If you take a well-validated Big Five personality test today, your results provide a reasonably accurate snapshot of where you currently stand on each trait dimension. But those scores are not permanent. Your Neuroticism score will likely be lower in ten years. Your Conscientiousness will probably be higher. Your Openness may decline slightly. And if you deliberately work on a particular trait — through therapy, habit change, or environmental restructuring — you may accelerate or redirect those changes.
The most useful way to think about personality test results is not as a permanent label but as a baseline measurement. It tells you where you are starting from, which is valuable information for anyone interested in personal growth. If you want to explore your current profile, tools like personalitree.com offer both Big Five and 16-type personality assessments that provide that starting point — useful not as a verdict on your character, but as data for the changes you might want to make.
The Balanced View: Neither Fixed Nor Fluid
The evidence paints a picture that avoids both extremes. Your personality is not a cage — research on intentional change, therapy, and life experiences demonstrates meaningful plasticity, particularly for Neuroticism and Conscientiousness. But your personality is also not a blank canvas — genetic predispositions, early-life experiences, and decades of habit create inertia that makes radical transformation unlikely.
Perhaps the most useful framework is to think of personality as a landscape with defined boundaries but considerable interior space. You cannot turn a mountain into an ocean, but you can build roads, plant forests, and redirect rivers within the terrain you have. The research on personality change suggests that most people have more room to move within their landscape than they realize — and that the movement happens through the quiet accumulation of daily choices, not through dramatic self-reinvention.
Websites like personalitree.com can help you map that landscape by showing where you fall on the key personality dimensions. The map is not the territory, and the territory is not fixed. But knowing both gives you something more valuable than either alone: the ability to navigate on purpose.
