How to tell if you have a changeable personality according to science

Most people believe they are far more capable of changing their personality than they actually are. This is hardly surprising. Humans are deeply invested in flattering illusions about themselves. We routinely overestimate our intelligence, morality, attractiveness, and future prospects. Psychologists refer to this as the “better-than-average effect,” though “wishful narcissism” might be more precise. Unsurprisingly, personality is no exception. We like to imagine ourselves as unfinished masterpieces rather than stubbornly repetitive creatures of habit who have already maxed out on their limited potential. (Not sure about you but, in my case, the former is definitely true!) And yet all it takes is attending one of those excruciating high-school reunions to realize how little people really change. The former class bully may now wear Patagonia vests and discuss real-estate investments, but the same appetite for dominance usually lingers beneath the surface. The class clown still hijacks conversations for attention. The agreeable people remain agreeable, the anxious remain anxious, and the narcissists, now armed with social media and AI, become even more efficient at self-promotion. Physically, of course, many people change quite dramatically, usually in directions that inspire nostalgia rather than envy. Psychologically, however, most remain recognizable versions of their younger selves, both for good and for bad. Fiction understood this long before psychology did. At the end of The Godfather, Michael Corleone assures Kay that things will be different, that he will become a better man than the one circumstances and ambition have turned him into. By the sequel, personality has won. Shakespeare built entire tragedies around the same premise: Character is destiny. Modern psychology, though less poetic, reaches broadly similar conclusions. Personality traits are remarkably stable across adulthood, especially after the age of 30. Longitudinal research consistently finds tha