A psychologist conducts research using the twin-study method. He administers a need for Achievement scale to sets of monozygotic and dizygotic twins and finds a correlation of .50 between the scores for pairs of monozygotic twins. If this study is to demonstrate evidence for a genetic influence on need for Achievement, what would we expect the correlation to be between scores for pairs of

dizygotic twins?

A. Higher than .50
B. Lower than .50
C. Very close to .50
D. There is no way to demonstrate a genetic influence with these data.

B