If you take a child from his/her biological parents and place him/her in an adoptive care, a most permanent kind of environmental change, if the adopting parents are more educated and have better socioeconomic circumstances than the biological parents, that child will be more intelligent than his/her siblings.
Siblings and IQ have environmental associationCredit: Wikimedia Commons
This is the result of a study by some researchers at Virginia Commonwealth University, the University of Virginia and Lund University in Sweden. It places high authority to the claim that environmental circumstances such as educational level of the parents as well as their socioeconomic status has a high impact on the cognitive abilities of children even down to their early adulthood.
This also rends credence to the claim that DNA or one’s genes has influence on intelligence.
So, factors influencing IQ resides both within and outside the person.
