Which of the following is the best evidence for a genetic contribution to intelligence
A)the high correlation between intelligence scores of roommates
B)the fact that test scores of identical twins reared together tend to be more highly correlated than the scores of identical twins reared apart
C)the fact that intelligence scores of identical twins tend to be more similar than those of fraternal twins
D)the fact that intelligence scores of fraternal twins tend to be more similar than those of non-twin siblings

Question

Quizplus · Accepted Answer

The fact that intelligence scores of identical twins (who share 100% of their genes) tend to be more similar than those of fraternal twins (who share on average 50% of their genes) provides strong evidence for a genetic contribution to intelligence. This comparison controls for environmental factors to a large extent, as both types of twins typically grow up in the same environment.

Which of the Following Is the Best Evidence for a Genetic