What was the average age of the twins studied by Brendgen?

• A. 4 years old
• B. 6 years old
• C. 8 years old
• D. 10 years old

Answer: (B)

The average age of the twins studied by Brendgen was 6 years old. This age is significant because it aligns with a developmental stage where children are beginning to form social relationships outside of their immediate family. At this age, twins may exhibit distinct social behaviors and personality traits that can be observed and analyzed, especially in the context of the study's focus on the interplay between genetic predisposition and environmental influences on behavior. The age of 6 is a critical period in which researchers can assess the emergence of various social competencies, making it relevant for understanding the dynamics of twin interactions and relationships.