Which of the following is the best evidence that genetics plays an important role in determining intelligence?
A) Identical twins raised apart have more similar IQs than fraternal twins raised together.
B) Fraternal twins raised together have more similar IQs than non-twin siblings raised together.
C) Children have IQs that are more similar to the IQs of their siblings than to the IQs of their parents.
D) Children adopted from different biological parents but raised by the same adoptive parents have fairly similar IQs as young children.

Question

Quizplus · Accepted Answer

Identical twins have the same genetic makeup, whereas fraternal twins share only 50% of their genes. Therefore, if identical twins raised apart have more similar IQs than fraternal twins raised together, it suggests that genetics play a significant role in determining intelligence. This is because any similarities between the IQs of identical twins raised apart can only be attributed to genetic factors, as their environmental and social experiences are likely to be very different.

Which of the Following Is the Best Evidence That Genetics