"Winick, Meyer, and Harris (1975) found 141 Korean children adopted as infants by American families exceeded the national average in both IQ and achievement scores when they reached 10 years of age. The principal interest of the investigators was on the possible effects of severe malnutrition on later intelligence, and many of these Korean children had been malnourished in infancy. When tested, those who had been severely malnourished as infants obtained a mean IQ of 102; a moderately well-nourished group obtained a mean IQ of 106; and an adequately nourished group obtained a mean IQ of 110....Neither the social class of the adopting parents nor the number of years the child spent in the adopted family had any effect on the child's IQ."
http://www.udel.edu/educ/gottfredson/30years/Rushton-Jensen30years.pdf(P.250)
Even the severely malnourished Korean children went on to have an IQ above the national average in America.
I'm not making a point about nutrition, I'm making a point about what can and cannot be infered from the heritability statistic.
