Yes, ColinsMum. Even I, non-mathematically gifted person, thought it was nonsensical to add the standard deviations like that. In addition in the previously linked slides he seems to present the regression to the mean of IQ scores in children as a fact, but in this blog post it's obviously conjecture. I think you've made other good points too, about picking populations for the supposed regression, etc. I'd buy perhaps that some regression happens in children, but not the way it's been presented.

Striving to increase my rate of flow, and fight forum gloopiness. sick