The best evidence supporting the role of genetic factors in intelligence is provided by studies that compare
A) children to both their biological and adoptive parents.
B) identical and fraternal twins.
C) people born in different generations since the 1930's.
D) children raised in poverty and middle-class children.

Question

Quizplus · Accepted Answer

Studies that compare identical and fraternal twins provide the best evidence supporting the role of genetic factors in intelligence. This is because identical twins share 100% of their genes, while fraternal twins share only 50%, just like any other sibling pair. Therefore, any differences in intelligence between identical twins are likely due to genetic factors, while differences between fraternal twins could be due to both genetic and environmental factors.

The Best Evidence Supporting the Role of Genetic Factors in Intelligence