that increases BMI by roughly six units for each risk allele among those without a college degree but is unrelated to BMI for those with a college degree. Figure 4 illustrates the difficulty in testing the diathesis-stress (zones 4 and 5) vis-à-vis the social push (zones 2 and 7) model. There is evidence for both of the models, they seem to be equally likely, and the distribution of the effects does not appear to be different from a random environment. Consider the 349 interesting SNPs (those with p values less than 10−3) for the college graduates (the upper-left quadrant of the figures on the right). Among these SNPs, 316 did not reach p < .10 for the non–college group, suggesting that roughly 90 % of the SNPs that predict BMI for college graduates are not associated with BMI among non–college graduates. This might seem to provide strong support for the social push perspective. However, 87 % of the SNPs that predict BMI for non–college graduates (n = 258) are roughly equal to zero for college graduates, and very similar results are shown for the simulated environment (90 % and 94 %, respectively). Again, the difference is very slight, with no
