Your Personality Might Be Completely Different in 10 Years: Surprising Changes in Humans Revealed by Recent Research

Was "Personality Doesn't Change" Just an Assumption? The Surprising Truth About Your "True Self" Revealed by Data from Over 160,000 People

"I'm not good with people because of my personality."

"He's always been meticulous."

"That person never changes, no matter how old they get."

In our daily lives, we often make snap judgments about people's personalities with surprising ease.

When you change jobs, your income changes. As you age, your physical strength and health change. When you start a family, move, or experience major failures or successes, your life satisfaction changes too.

However, when it comes to "personality," it's a different story.

Many people tend to think of traits like being extroverted or introverted, meticulous or sloppy, anxious or optimistic as relatively fixed characteristics deep within a person.

However, a study published in the academic journal "Communications Psychology" in July 2026 challenges this notion.

In conclusion, human personality is not as stable as we think.

Moreover, the extent of change was not just a matter of differing impressions.

Researchers analyzed multiple large-scale longitudinal surveys and found that the amount of personality change was not insignificant compared to changes in life satisfaction, self-esteem, health, and income—things that change throughout life.

First, 887 People Were Asked, "How Much Do You Think People Change?"

What makes this study interesting is that it investigated "what kind of image people have about personality" before examining actual personality changes.

The research team asked 887 adults representing the general U.S. population how much they think various human traits change between the ages of 15 and 90.

It wasn't just personality that was targeted.

Over 20 different items, including health, income, sleep, exercise, self-esteem, and life satisfaction, were compared.

A distinctive trend emerged.

Respondents believed that health, income, and lifestyle habits change with age, while personality was judged to be "relatively unchangeable."

In other words, among the many human traits, we tend to think that "only personality is specially fixed."

But is that really the case?

Results from Analyzing Data from 167,971 People in Four Countries

The research team then analyzed actual long-term data.

They used eight large-scale longitudinal surveys conducted in the United States, Germany, Australia, and the Netherlands.

The total number of subjects was 167,971.

By using data that tracked the same individuals over a long period, rather than just comparing many people at one point in time, they analyzed how individual traits change with age.

As a result, it was found that there was a discrepancy between the prediction that "personality is quite stable" and the actual data.

Major personality traits showed considerable change throughout life.

What's more important is that these changes were not particularly small compared to life satisfaction, self-esteem, subjective health, and income.

In some cases, personality showed greater lifetime changes than other items.

We tend to think "income changes but personality doesn't," but looking at long-term data, it's not that simple.

What Are the "Big Five" Personality Traits?

In this study, the five personality traits known as the "Big Five," widely used in psychology, were analyzed.

The first is "Extraversion."

It relates to whether one enjoys interacting with people, is active, or seeks stimulation.

The second is "Agreeableness."

It represents tendencies such as compassion, trust, and willingness to cooperate with others.

The third is "Conscientiousness."

It relates to planning, responsibility, self-management, and the tendency to see things through to the end.

The fourth is "Neuroticism."

It indicates the degree to which one experiences negative emotions such as worry, anxiety, depression, and stress.

And the fifth is "Openness."

It relates to interest and curiosity in new experiences, ideas, cultures, arts, and knowledge.

According to the research results introduced by WELT, Extraversion, Openness, and Neuroticism tend to decrease on average over a long life, while Agreeableness and Conscientiousness tend to increase. Particularly, the lifetime change in Conscientiousness was relatively large.

Of course, this doesn't mean "everyone changes in the same way."

Some people become more sociable than when they were young, while others come to prefer time alone.

What's important is that the image of "personality hardly moving" on average does not match reality.

Why Does "Responsibility Increase with Age"?

Why does personality change?

This study alone cannot fully explain the causes of change.

However, it's easy to imagine that the social roles we experience in life are not unrelated to personality.

When a student enters society, they are required to work at set times, meet deadlines, and fulfill promises with others.

Someone who was a subordinate may become a boss.

They may start living with a partner after getting married, have children, or start caring for their parents.

When the actions required in daily life change, habits also change.

As a result of repeating those habits for 10 or 20 years, what is called "that person's character" itself may change.

Personality doesn't just produce behavior.

The accumulation of behavior and environment also affects personality.

With that in mind, it's not surprising that someone who was very sloppy in their youth becomes more organized through work and family life.

Is "Mellowing with Age" Not Just a Myth?

In Japan, the expression "mellowed compared to when they were young" is often used.

Things that used to make one angry are no longer bothersome.

One doesn't judge others' flaws as harshly as before.

One becomes more forgiving of their own failures.

Research also shows that, on average, Neuroticism decreases over a lifetime.

Of course, individual differences are significant, but it's quite possible that through years of experience, one encounters more situations where they can judge, "This much is okay," or "It worked out before."

What seemed like a major life issue in youth may be seen as "something similar happened before" decades later.

Humans may change the way they react to events by accumulating experiences.

So, What Is the "True Self"?

What makes this study intriguing is that it goes beyond mere personality psychology.

It relates to the very concept of the "true self."

We often use expressions like "live true to yourself," "find your true self," and "be honest with yourself."

These imply the existence of a "real self" deep inside that is unaffected by external influences.

But if personality itself changes over decades, which version of yourself is the "true self"?

Is it the self at 20?

The self at 40?

The self at 80?

Perhaps all of these are the "true self."

What researchers are questioning is not the idea of the "true self" itself, but the tendency to view it as overly fixed.

"I've always been anxious, so I can't change."

"I'm introverted, so I can't speak in public."

"I'm not a planner, so it can't be helped."

Thinking this way closes off possibilities before trying new actions.

Even if personality can't be changed at will, knowing that "the current self is not the final version of the future self" is significant. The original article also points out that considering personality as immutable may weaken the motivation to change behaviors or traits.

However, It's Not About "Anyone Can Become a Different Person with Effort"

It's important not to interpret the research results too much in a self-help manner.

This study shows that "personality changes," but it doesn't prove that "you can become any personality you want if you wish."

The existence of average changes found in large-scale surveys and the ability of an individual to change their personality in a targeted direction are separate issues.

Moreover, personality has both changeability and stability.

For example, even if Extraversion decreases with age across society, someone who was very sociable when young may still be sociable compared to their peers when older.

The original article also explains that even if average personality traits change, the "relative position to others" may remain relatively stable.

In other words, personality is neither a completely fixed statue nor clay that can be reshaped freely.

It might be more like a landscape that changes shape gradually over many years.

Reactions to the Article Range from "That's Obvious" to "I'm the Opposite"

What's interesting is the general public's reaction to this research.

In the comments section of WELT, not everyone took the research results as a fresh discovery.

There were multiple opinions questioning the novelty of the research, saying, "Hasn't it always been known that people change with age?"

Some readers felt that "I'm actually the opposite" of the average trends shown in the research.

Even after reading about changes in traits like Extraversion and Openness with age, they don't see it applying to their own lives.

This is a typical reaction to statistical research.

What the research shows is an "average trend," not a future prediction that applies to every individual.

Other comments expressed a desire for concrete suggestions on how to actually change, even if they understand that people change.

There were also posts connecting the result that Agreeableness increases with age to jokes about marital relationships, showing that many read the academic theme in relation to themselves or their close relationships.

On Social Media, Debates on Whether Personality Tests Reflect the True Self

As of now, the debate on social media about this paper itself is still limited.

However, around the same time on platforms like Reddit, discussions such as "Do personality test results reflect the true self?" and "Why do test results differ from a few years ago?" are active.

In a Reddit thread posted in August 2026, based on the experience of differing results from past and recent personality tests, the view was presented that "personality tests measure tendencies of thought, emotion, and behavior at that point in time, rather than discovering an unchanging essence."

In another Big Five-related thread, users who feel their test results differ from past to present and those who think personality expression changes with living conditions and psychological states can be seen.

Of course, personal experiences on social media cannot be treated on par with academic research.

However, it's interesting that many people have doubts in real life about whether "the old self and the current self are the same."

The changes shown by research data partially overlap with such personal feelings.

The Danger of Making Personality Tests Your "User Manual"

Recently, personality tests have become very popular, especially on social media.

Whether one is introverted or extroverted.

What kind of job suits them.

What kind of behavior they tend to exhibit in romance.

Who they are compatible with in relationships.

The results are interesting as a starting point for understanding oneself.

The problem is using those results as a "user manual for an unchanging future self."

"I'm this type, so I can't work in sales."

"I'm introverted, so I can't be a leader."

"I won't date this type of person because we're incompatible."

Such judgments risk fixing current tendencies into the future.

Personality research shows a more complex picture, where humans have a certain continuity but also change with experience and age.

Personality tests can serve as a map to know your current location, but they don't determine your life's destination.

The Need to Update the