Agreeableness demonstrated a fairly linear increase with age whereas the pattern for Conscientiousness was curvilinear: scores increased up to a peak somewhere between the ages of 50 to 70 and then declined. Average levels of Neuroticism generally declined with age but increased slightly starting around age 80.

Do people become more agreeable as they age?

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.

Does openness to experience increase with age?

1. The average change in Openness was fairly small, but showed a slight increase with age, but there were individual differences in change: 12.6% of people decreased, 17.5% increased, 69.9% did not show reliable change.