Which of the following family relationships shows the most similarity in measured intelligence?

Question

Quizplus · Accepted Answer

Research has consistently shown that monozygotic (identical) twins have a higher correlation in measured intelligence than siblings or dizygotic (fraternal) twins, indicating that genetic factors play a larger role in intelligence than environmental factors such as shared upbringing. Adopted children and their siblings may have different biological parents, making it difficult to determine the relative influence of genetics and environment.

Which of the Following Family Relationships Shows the Most Similarity