Final answer:
Behavioral geneticists use adoption studies to compare the rates of a trait among biologically related relatives and adopted relatives to determine the relative influence of heredity and environment.
Step-by-step explanation:
Behavioral geneticists use adoption studies to determine the relative influence of heredity and environment on a trait by comparing the rates of that trait among biologically related relatives and adopted relatives. Adoption studies provide insight into the way our temperaments, preferences, and abilities are shaped by our genetic makeup versus our social environment.