Personality is the pattern of thoughts, feelings and behaviors unique to a person. People tend to think of personality as fixed. But according to psychologists, that’s not how it works. “Personality is a developmental phenomenon. It’s not just a static thing that you’re stuck with and can’t get over,” said Brent Roberts, a psychologist at the University of Illinois at Urbana-Champaign.
…[One study] found that in their 60s, participants scored much higher than they had as teenagers on questions measuring calmness, self-confidence, leadership and social sensitivity.
Again and again, longitudinal studies have found similar results. Personality tends to get “better” over time. Psychologists call it “the maturity principle.” People become more extraverted, emotionally stable, agreeable and conscientious as they grow older. Over the long haul, these changes are often pronounced.
Some individuals might change less than others, but in general, the maturity principle applies to everyone. That makes personality change even harder to recognize in ourselves — how your personality compares with that of your peers doesn’t change as much as our overall change in personality, because everyone else is changing right along with you.
“There’s good evidence that the average self-control of a 30-year-old is higher than a 20-year-old,” [psychologist Brent] Donnellan said. “At the same time, people who are relatively self-controlled at 18 also tend to be relatively self-controlled at age 30.”