Question

What have adoption studies revealed about the genetic and environmental contributions to intelligence?

Answer 1

What have adoption studies revealed about the genetic and environmental contributions to intelligence?

It is not easy to separate the influence of environment as well as heredity on the characteristics of humans. People having similar genetic make up have always been living in similar environments and thus we see similarities in the intelligence level of people living in the same family. And thus, it is not possible to know if the similarities occur due to the genetic make up of the people or the environment in which they are living in. And hence, adoption studies carried out to identify if the effects are from the environment or the genes.

In adoption studies, both identical twins as well as fraternal twins had been used so as to understand how heredity would affect intelligence. Since identical twins would be sharing 50% of their genetic make up, if the identical twins would be having more similar intelligence as compared to the fraternal twins, it could be concluded that heredity would be influencing intelligence.

In adoption studies, the effects of heredity from the environment, the adopted children would be compared to their biological parents and their adopted parents. Adopted children would be similar to their biological parents in their genetic make up and environment would be more close to the adopted parents. It has been seen that the adopted children would be having intelligence that is more close to the biological parents as compared to the adopted parents. Thus, it would mean that children up for adoption, from parents having high intelligence, would be having high intelligence, despite their adopted parents not being as intelligent.