Can Your Personality Change? The Science of Personality Change

The Old View: Personality Is Fixed

For much of the 20th century, personality was considered largely immutable after about age 30. William James wrote in 1890 that "in most of us, by the age of thirty, the character has set like plaster, and will never soften again." Research through the 1980s generally supported this view.

The New View: Personality Changes Throughout Life

The last two decades of research have overturned the fixed-personality view. Here's what we now know:

Personality Changes Gradually Across the Lifespan

Multiple large longitudinal studies — tracking the same people for decades — show consistent patterns:

• Conscientiousness increases through young adulthood and into midlife, particularly around work and family milestones
• Agreeableness increases with age, especially after 50
• Neuroticism generally decreases across adulthood — people become more emotionally stable on average
• Extraversion shows mixed trends — social vitality may decline, but assertiveness may increase
• Openness peaks in young adulthood and shows some decline in later life

This pattern — sometimes called the "maturity principle" — makes evolutionary sense. As people take on adult responsibilities, they become more reliable, cooperative, and emotionally stable.

Life Events Drive Change

Landmark studies by Brent Roberts and colleagues show that life experiences can change personality:

• Starting a new job increases Conscientiousness and Extraversion
• Entering a romantic relationship increases Agreeableness and Conscientiousness
• Becoming unemployed decreases Conscientiousness and increases Neuroticism
• Bereavement temporarily increases Neuroticism
• Major health events can shift multiple traits simultaneously

The key insight: who you are is partly a function of the life you're living. Put yourself in environments that demand different things, and your traits will respond.

Therapy Can Change Personality

A 2017 meta-analysis in Psychological Bulletin found that psychotherapy produces reliable changes in Big Five traits — not just in symptoms. Effect sizes were:

• Neuroticism: moderate decrease (d = -0.59)
• Extraversion: moderate increase (d = +0.35)
• Conscientiousness: small-moderate increase (d = +0.29)
• Agreeableness: small increase (d = +0.25)
• Openness: small increase (d = +0.22)

Cognitive-behavioral therapy showed especially strong effects on Neuroticism and Conscientiousness.

Deliberate Change Efforts Work

A 2021 study in PNAS gave participants personalized coaching based on their desired trait changes. After 10 weeks, participants who wanted to change (on specific traits) showed significantly greater changes in those traits compared to control groups. The effect wasn't huge, but it was real and sustained at follow-up.

What Doesn't Change Easily

Not all traits are equally plastic. The most heritable traits — and especially those most rooted in temperament and neurobiological systems — are the hardest to shift:

• High Neuroticism is deeply wired into fear-learning and threat-detection systems. Therapy helps, but it tends to reduce its impact rather than eliminate the underlying sensitivity.
• Introversion/Extraversion fundamentally relates to reward sensitivity and arousal thresholds. Social skills can increase. The underlying energetic preference changes less.
• Openness correlates with cognitive style — how your brain processes novelty. This doesn't change much with effort.

The Distinction Between Change and Growth

Here's a crucial nuance: the goal of self-development isn't necessarily to change your personality traits. It's to:

1. Develop skills that compensate for trait limitations — an introverted person can learn excellent social skills, even if the underlying energetic preference doesn't shift

2. Reduce the shadow expression of your traits — a high-Neuroticism person may always be sensitive, but can develop emotional regulation skills that change what they do with that sensitivity

3. Create environments that fit your traits — a low-Conscientiousness person might not become highly organized, but they can design systems (external structure) that produce organized outcomes

This is the Innermind approach: we don't tell you to become someone else. We help you understand your pattern clearly enough to work with it skillfully.

Tracking Change Over Time

Innermind's growth tracking feature lets you retake assessments at regular intervals and see how your scores change. Many users find this both validating (seeing real progress) and instructive (noticing what hasn't changed, and why).

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