Key Concepts

• Studies of personality development often focus on traits such as extroversion, conscientiousness, agreeableness, neuroticism and openness to new experiences. In most people, these traits change more during young adulthood than any other period of life, including adolescence. Openness typically increases during a person’s 20s and goes into a gradual decline after that.
• This pattern of personality development seems to hold true across cultures. Although some see that as evidence that genes determine our personality, many researchers theorize that personality traits change during young adulthood because this is a time of life when people assume new roles: finding a partner, starting a family and beginning a career.
• Personality can continue to change somewhat in middle and old age, but openness to new experiences tends to decline gradually until about age 60. After that, some people become more open again, perhaps because their responsibilities for raising a family and earning a living have been lifted.