There are a lot of theories out there explaining the influences of IQ and it all falls back on the big question Nature or Nurture.
Today, nearly all psychologists recognize that both genetics and the environment play a role in determining intelligence. It now becomes matter of determining exactly how much of an influence each factor has.
Here are some arguments for each side.
Evidence of genetic influences:
• Twin studies suggest that identical twins IQ's are more similar than those of fraternal twins
• Siblings raised together in the same home have IQ's that are more similar than those of adopted children raised together in the same
Evidence of environmental influences:
• Identical twins reared apart have IQ's that are less similar than identical twins reared in the same environment
• School attendance has an impact on IQ scores
• Children who are breastfed during the first three to five months of life score higher on IQ tests at age 6 than same-age children who were not breastfed
I found it very interesting that there has been significant data proving Genetic influences on IQ. The article I posted below shows this direct prove of Genetic influence "Large sample size studies in monozygotic (MZ) and dizygotic (DZ) twins raised together show an average correlation of .86 for MZ twins, while the correlation for DZ twins is only .60." Over all if I had to weigh it out I believe that environmental factors influence intelligence significantly more than genetics, What do you guys think?