Even after watching, the question remains whether the studies cited to back Haier's claims managed to adequately address the externalities caused by inadequate neo-natal / post-natal care. He states the results are unaffected by socioeconomic disparity....but science is about measurement, and there's not been one MRI/EEG long-term study, infancy to adolescence, to scientifically substantiate TRUE genetic starting point of either subjects or control.<br><br>Also, he states socioeconomic status may add to the G-factor but that it does not substantially detract... <br>However, none of the studies cited have measured whether genetic ability shrinks due to poor circumstance. We know that neuronal pathways develop and winnow over the course of our lifetime, and we know that continuous stress negatively impacts brain function (and the autoimmune system), giving rise to conditions which impede neuronal development. Lacking longterm pre/post-natal medical data (MRIs, nutrition index, etc) for subjects and controls, we cannot truly ascertain the impact of stressors on G-factor! Children from disadvantaged backgrounds whose hierarchy of needs constantly fluctuate between shelter and self-esteem concerns from infancy through adolescence (when these tests are administered), may experience adversity which reshapes behavior, thus impeding neuronal activity. One possibility is that scarcity of nutrients coupled with early childhood insecurity-induced stress (paucity of shelter, food, positive attention) may be responsible for neuronal winnowing? Brains forced into perpetual survival mode in order to contend with extreme external challenges, not faced by offspring from stable childhood backgrounds, might miss important developmental windows, some which serve to advance compound reasoning skillsets necessary for unlocking one's full genetic potential. We just don't know enough about the brain to rule out the significance of these factors Haier's cited studies casually omit.