- Studies identifying whether nature vs nurtur
-Can be more useful than twin studies because they can experience same physical, family and social environment which can make it difficult to determine environmental/genetic
-Adoption studies may look for correlation between aggression in children, biological/adoptive parents or twins separated.
P- Hutchings and Mendick investigated 14,000 Denmark adoptions
E- Found a significant correlation
E- Between number of criminal convictions for violence in biological parents, mainly fathers similar in adopted children
L- Nature as similar characteristics to adopted dad.
Miles and Carey