Bob O'Hara and GrrlScientist: Why Gerald Crabtree's speculations about declining human intelligence are wrong...
It has often been observed that scientists, some rather brilliant, can get things hopelessly wrong when they stray outside their field. Examples are legion, and it has been dubbed the Linus Pauling effect:
"The phenomenon is a familiar one: let's call it "the Linus Pauling effect." A highly respected and honored senior scientist, largely out of the mainstream and not up to date with the recent developments (and perhaps a bit senile), makes weird pronouncements about their pet ideas – and the press, so used to giving celebrities free air time for any junk they wish to say, prints and publishes it all as if it is the final truth."
Normally this happens when, say, a physicist starts thinking too hard about brains, but embarrassingly for me (one of my many sins is to be a geneticist), geneticists have a penchant for this too. What is really embarrassing is that more than one has made this mistake with a pet idea about genetics. I will now admit that I am going to step outside of my area of expertise (particularly with respect to human evolution and psychology), so if you are more knowledgeable in these areas, you can have some fun correcting my mistakes.
One classic case is John Sanford and his ideas about genetic entropy. Sanford was a well respected geneticist, most famous for working out that one way of creating GM crops was to shoot them with gold (I was involved – briefly – in a project trying to do this to mildew). He steadily converted to a literal Christian position, including young earth creationism. Being a geneticist, he was faced with the problem of evolution, and wrote the book, Genetic Entropy, where he argued that the human gene pool was degenerating. Amongst the evidence he used for this conclusion was the reduction in the reported ages of people from the Old Testament.