Which of the following observations provides the BEST evidence that intelligence test scores are influenced by heredity?
A) Japanese children have higher average intelligence scores than do American children.
B) Identical twins raised together are more similar in their intelligence scores than identical twins raised separately.
C) The intelligence scores of children are positively correlated with the intelligence scores of their parents.
D) Identical twins reared separately are more similar in their intelligence scores than fraternal twins raised together.

Question

Quizplus · Accepted Answer

Identical twins reared separately have the same genetic makeup, so any similarities in their intelligence scores must be attributed to genetic factors rather than environmental factors. The fact that they are more similar in their intelligence scores than fraternal twins, who share only half of their genes, provides strong evidence that heredity plays a role in intelligence.

Which of the Following Observations Provides the BEST Evidence That