What have twin studies revealed about intelligence?
A) Intelligence is completely influenced by environment.
B) Intelligence is partly influenced by heredity.
C) Dizygotic twins have almost identical IQ scores.
D) Monozygotic twins have very different IQ scores.

Question

Quizplus · Accepted Answer

Twin studies have consistently found that intelligence is partly influenced by heredity. Monozygotic twins (who share 100% of their genetic material) have IQ scores that are more similar to each other than dizygotic twins (who share only 50% of their genetic material), indicating a genetic influence on intelligence. However, the fact that monozygotic twins don't have identical IQ scores suggests that environment also plays a role.

What Have Twin Studies Revealed About Intelligence