Researchers have found that siblings' scores on standard measures of personality traits are virtually uncorrelated. Discuss how parental treatment of their children can serve as a nonshared environmental influence. Give an example of how differential treatment might affect two siblings.

What will be an ideal response?

Because siblings share common genetic and environmental influences (shared environmental influences), they are expected to develop similar personalities. However, adolescents vary widely in personalities. Research suggests that nonshared environmental influences are stronger than shared environmental influences during adolescence. One important nonshared environmental influence during adolescence is differential treatment by parents. Unequal treatment from parents can create conflict among siblings; however, when differential treatment is not seen as unfair, it can have a positive effect on siblings--they actually get along better.

Fifteen-year-old Akshara is introverted and prefers to spend her free time in her room writing and watching films. Her 13-year-old brother Akshay is very social and enjoys spending time with his parents, whether it's running errands, helping around the house, or just relaxing as a family. Although their mother would prefer to spend time with both of them, she allows Akshara to spend much of her time alone, and she does her best to include Akshay in as many activities as possible. Because their mother is sensitive to their needs, Akshara and Akshay feel understood and unique and are less likely to engage in sibling rivalry.

Key Points:

a) Nonshared environmental influences are stronger than shared environmental influences during adolescence.

b) Parental treatment of their children can be a nonshared environmental influence (parents treat one child differently from the other).

c) Differential treatment that is unfair can be detrimental to sibling relationships, while differential treatment that makes siblings feel unique has a positive influence.