> The most elegant proof of IQ being linked to genetics: > > The same person taking an IQ test twice has mean correlation of 0.85 or above in their scores. Identical twins reared together: 0.86 Identical twins reared apart: 0.76 Biological parent and child: 0.42 Adoptive parent and child: 0.19 And of course, any two random people will have a correlation close to 0.

How is this proof of IQ being linked to genetics if adoptive parents can have 1/2 of the correlation that identical twins have? I think this proves that genetics only has a minor part, and upbringing/environment seems to be the most important factor.