Final answer:
Agreeableness and conscientiousness tend to increase with age, with conscientiousness peaking in middle age and agreeableness in late adulthood.
Step-by-step explanation:
The traits of agreeableness and conscientiousness tend to increase as we age. While some personality traits remain fairly stable over the lifespan, these two have been found to show growth, particularly conscientiousness which increases through young adulthood into middle age.
Agreeableness peaks between 50 to 70 years old. Other traits such as neuroticism and extraversion generally have been found to decline slightly with age.