Final answer:
In adulthood, the Big Five personality traits of conscientiousness and agreeableness are likely to increase, particularly with conscientiousness rising into middle age and agreeableness peaking between 50 to 70 years.
Step-by-step explanation:
The Big Five personality traits model suggests that conscientiousness and agreeableness are likely to increase somewhat during adulthood.
- Conscientiousness, which describes traits such as organization, discipline, and dependability, tends to increase from young adulthood into middle age, as individuals become better equipped to manage personal relationships and career tasks.
- Similarly, agreeableness, characterized by being pleasant, cooperative, and good-natured, often peaks between ages 50 to 70. These traits, part of the broader Five Factor Model, have demonstrated relative stability over the lifespan but show a tendency for slight increases or decreases as a person ages.