He should have done better research. Given the date of his paper, he wouldn't have been able to see the current review article on the issue, Nisbett, R. E., Aro

He should have done better research. Given the date of his paper, he wouldn't have been able to see the current review article on the issue, Nisbett, R. E., Aronson, J., Blair, C., Dickens, W., Flynn, J., Halpern, D. F., & Turkheimer, E. (2012). Intelligence: new findings and theoretical developments. American Psychologist, 67(2), 130. http://www.apa.org/pubs/journals/releases/amp-67-2-130.pdf http://www.apa.org/pubs/journals/releases/amp-67-2-130.pdf but he should have known about most of the earlier studies cited in that review article. If he knew the research better, he would not have written as he did.