Gaussian distributions are symmetrical, which means every argument about what happens at the high end equally applies to the low end. That's not what the articl

Gaussian distributions are symmetrical, which means every argument about what happens at the high end equally applies to the low end. That's not what the article says: it says the low end (far below the mean) is highly correlated with performance, but the high end is not. By your argument, someone with an IQ of 70 should be more likely to be simply having a bad day than to have a natural "intelligence" (whatever TF that means) truly at that level. Edit: On second thought, the argument works a little better if you assume that the variance of the "daily fluctuation" distribution is proportional to the magnitude of the "innate" one, so someone with an "innate" 70 varies +/- 7 per day, but someone with an "innate" 150 varies +/- 15.