I didn't see any reason why these differences might not be genetic: genes cause changes in the brain which cause changes in academic achievement which cause socio-economic status.<p>It would be interesting to see studies that isolated the effects of genes and environment.
It's not immediately clear to me why those carrying out the study seem to interpret their results as justification for policy making and intervention. Serious question, is it not possible that we observe a cause and effect here? Ie. higher mental capacity leads to doing better in life?
Related: Your DNA may carry a ‘memory’ of your living conditions in childhood.<p><a href="http://scienceblog.com/48584/your-dna-may-carry-a-‘memory’-of-your-living-conditions-in-childhood" rel="nofollow">http://scienceblog.com/48584/your-dna-may-carry-a-‘memory’-o...</a>