Original sentence: The existence of a dysgenic trend in humans is often proposed by supporters of eugenics; however, the existence of a dysgenic effect has never been proven in humans, and is generally considered a fringe or even a junk science concept.While it may seem obvious that differential fertility would result in a progressive change in IQ, it is a fallacy that applies only to closed subpopulations
Edited sentence: Coleman however contends that Preston's and Campbell's model depends on assumptions which are unlikely to be true and argues that that their dismissal of the "common belief" in the case of IQ is not well founded.James S.While it may seem obvious that differential fertility would result in a progressive change in IQ, Preston and Campbell claim that it is a fallacy that applies only to closed subpopulations