Social scientists have long debated whether personality is stable throughout an entire lifetime or if it is more malleable. Previous research suggests it could be both, but longitudinal studies covering very long time-spans and relying on the same data source at both time points are rare.

In a new long-term study, researchers from the University of Houston found that personality is influenced by both genetics and environment. And while our broad patterns of thoughts, feelings and behaviors (essentials of our personalities) remain fairly consistent, they do mature or develop over time.

“Our findings suggest that personality has a stable component across the lifespan, both at the trait level and at the profile level, and that personality is also malleable and people mature as they age,” the researchers wrote in the Journal of Personality and Social Psychology.

Personality is described as patterns of thoughts, feelings and behaviors, consisting of five major traits: conscientiousness, agreeableness, openness to experiences, extraversion and emotional stability. These “Big Five” traits are found to be consistent across all ages and cultures. The combination of those traits — how dominant each trait is in relation to the other traits — creates one’s personality profile.

For the study, the researchers used a dataset of American high school students who answered a series of questions to assess personality in 1960 and again 50 years later. Data from the Project Talent Personality Inventory allowed the researchers to answer several questions, including the following:

  • To what extent do people maintain their relative standing on personality traits compared with other people. For example, do people who are more impulsive than most of their peers at age 16 remain more impulsive than their peers at age 60?
  • To what extent do average levels of personality traits change? Are people, on average, more conscientious at 66 than at 16?
  • Does everyone change in the same way?
  • Are there gender differences in patterns of personality stability and change across time?

“The rankings (of personality traits) remain fairly consistent. People who are more conscientious than others their age at 16 are likely to be more conscientious than others at 66,” said Dr. Rodica Damian, assistant professor of psychology at the University of Houston and lead author of the study. “But, on average, everyone becomes more conscientious, more emotionally stable, and more agreeable.”

The researchers found individual differences in change across time, with some people changing more than others and some changing in more maladaptive or harmful ways. Overall, men and women changed at the same rates across the lifespan.

The study is the first to investigate how one’s personality might change over 50 years and to rely on the same data source at both time points.

Source: University of Houston