Have you ever looked back at a younger version of yourself and thought, “I’m a completely different person now”? Or perhaps you’ve wondered if you can become more outgoing, more organized, or less anxious. The question of whether our core personality is fixed or fluid is one of the most enduring in psychology. For decades, the prevailing wisdom suggested that by age 30, our personality is “set like plaster.” But is that truly the case? Modern research offers a more nuanced and empowering answer.
This article delves into the science of personality change, using the renowned Big Five personality model as our framework. We’ll explore the evidence for both stability and malleability, investigate the life events that act as catalysts for change, and answer the crucial question: can you intentionally change your own personality?
Understanding the Big Five Personality Traits
Before we can discuss personality change, we need a common language to describe it. The Big Five, or the Five-Factor Model (FFM), is the most widely accepted and empirically validated framework for understanding personality structure. It posits that the vast majority of human personality can be described along five broad dimensions, often remembered by the acronym OCEAN:
- Openness to Experience: This trait reflects a person’s imagination, creativity, and intellectual curiosity. High scorers are adventurous and enjoy trying new things, while low scorers prefer routine and familiarity.
- Conscientiousness: This dimension relates to self-discipline, organization, and goal-directed behavior. Highly conscientious individuals are reliable and hardworking, whereas those low in this trait tend to be more spontaneous and less structured.
- Extraversion: This trait concerns sociability, assertiveness, and emotional expression. Extraverts draw energy from social interaction, while introverts (low on extraversion) find energy in solitude and quiet settings.
- Agreeableness: This reflects a person’s tendency to be cooperative, compassionate, and trusting. Highly agreeable people are often described as kind and helpful, while less agreeable individuals can be more competitive and skeptical.
- Neuroticism: Also known as Emotional Stability, this trait measures a person’s propensity to experience negative emotions like anxiety, anger, and sadness. High neuroticism is linked to emotional instability, while low neuroticism indicates emotional resilience and calmness.
This model provides a robust foundation for tracking how these fundamental aspects of who we are evolve—or remain constant—over the course of our lives.
The Stability Argument: Is Personality “Set Like Plaster”?
The idea that personality is largely fixed has deep roots. Psychologist William James famously wrote in 1890 that by age 30, the character has “set like plaster and will never soften again.” This “plaster hypothesis” was supported by early longitudinal studies that found a high degree of stability, particularly in adulthood.
Evidence Supporting Personality Stability
The evidence for stability comes from several key areas:
- Rank-Order Stability: This is the most compelling evidence for the plaster theory. It refers to a person’s relative standing on a trait compared to their peers. For example, if you are more extraverted than 80% of your friends in high school, you will likely still be more extraverted than most of them 20 years later. While everyone might become slightly less extraverted, your rank within the group remains remarkably consistent.
- Genetic Influence: Twin studies have consistently shown that genetics account for roughly 40-60% of the variance in Big Five traits. This substantial heritable component provides a biological anchor that contributes to the stability of our personality throughout life.
- Neurological Correlates: Our personality traits are not abstract concepts; they are linked to the structure and function of our brains. For instance, conscientiousness has been associated with the volume of the prefrontal cortex, a region critical for planning and self-control. These biological underpinnings contribute to the enduring nature of our dispositions.
This evidence paints a clear picture: our personality is not a blank slate. It has a strong, stable core that persists over decades.
The Change Argument: The Plasticity of Personality
While the plaster hypothesis holds some truth, modern research has chipped away at its rigid foundation, revealing that personality is more like clay than plaster—firm but still malleable. Psychologists now focus on two types of change: mean-level change and individual change.
How Personality Matures Over Time: Mean-Level Change
Mean-level change refers to how the average level of a trait changes for a whole population as it ages. Across cultures, researchers have observed a consistent pattern known as the “maturity principle.” As people move from adolescence into adulthood and middle age, they tend to experience positive personality shifts:
- They become more conscientious, driven by the demands of building a career and raising a family.
- They become more agreeable, as they invest in maintaining long-term relationships and contributing to their communities.
- They become less neurotic (more emotionally stable), learning to better regulate their emotions and cope with life’s stressors.
These changes are generally adaptive, helping individuals navigate the social roles and responsibilities of adult life more effectively. This gradual, predictable evolution shows that personality does, in fact, soften and reshape itself long after age 30.
Life Events as Catalysts for Individual Change
Beyond gradual maturation, specific life events can act as powerful catalysts for more rapid personality shifts. Our experiences shape us in profound ways, nudging our traits in new directions.
- Entering a Stable Partnership: Committing to a long-term romantic partner is consistently linked with decreases in neuroticism and increases in conscientiousness. The stability and mutual support in a healthy relationship can buffer against anxiety and encourage responsible behavior.
- Building a Career: Achieving success and taking on leadership roles at work often leads to increased conscientiousness and assertiveness (a facet of extraversion).
- Parenthood: Becoming a parent is a transformative experience that can significantly increase conscientiousness and agreeableness, though it can also cause a temporary spike in neuroticism due to stress and sleep deprivation.
- Significant Adversity or Trauma: While often leading to a rise in neuroticism, overcoming adversity can also foster post-traumatic growth, sometimes resulting in increased agreeableness and a new perspective on life (openness).
Can You Intentionally Change Your Personality? The Power of Volition
Perhaps the most exciting frontier in personality research is the study of volitional change—the idea that we can actively work to change our own traits. The answer appears to be a qualified “yes.” While you may not be able to transform from a deep introvert into a life-of-the-party extravert, you can certainly move the needle.
“Acting As If”: Behavior’s Impact on Personality
A key strategy for intentional change is rooted in a simple but powerful principle: behavior can change personality. If you want to become more conscientious, start by acting like a conscientious person. Set a goal to make your bed every morning, use a planner to organize your tasks, and consistently meet deadlines. Initially, this may feel unnatural, but over time, these new behaviors become habits. As your actions change, your self-perception and underlying thoughts and feelings begin to align with them. This “fake it ’til you become it” approach is a cornerstone of cognitive-behavioral therapy (CBT).
Therapeutic Interventions for Personality Change
Clinical interventions provide strong evidence for intentional personality change. Psychotherapies like CBT are highly effective at reducing neuroticism by teaching individuals new ways to manage anxious thoughts and behaviors. Similarly, mindfulness practices have been shown to increase agreeableness and emotional stability. These structured interventions demonstrate that with the right tools and commitment, significant personality change is achievable.
Conclusion: Embracing the Duality of Stability and Change
So, can personality change? The answer is not a simple yes or no. It’s both. A better way to think about personality is to use the analogy of a river. Your genetics and early experiences carve the river’s main channel—this is your stable, core disposition. However, life events, maturation, and your own intentional efforts are like rainfall and currents that can alter the river’s flow, widen its banks, and even carve out new paths over time.
Your personality is a dynamic interplay between a stable core and a capacity for change. You will likely always recognize the fundamental “you,” but that doesn’t mean you are stuck. Understanding this duality is incredibly empowering. It acknowledges the consistent self you know and love while opening the door to personal growth and development. We are not just passive recipients of our traits; we are active architects of who we are and who we want to become.
