"Actual evidence from Razib would, of course, have dominated other considerations."

To make the evidence compact I'd have to produce some charts showing that when a new large effect QTL is published there's often a media blitz (perhaps via # of articles published as a function of time), but that as time passes the finding is not validated by subsequent researchers using a wider set of populations. As it is, what I have is personal experience of being excited about a new QTL repeatedly, and then being disappointed. And lots of personal communication as to the reality of what Carl Shulman is talking about re: publication bias and fiddling around with experiments until the p-value comes out correct from my friends working in genomics, psychology and the interstices.

If I were naked to the field, I would go to google scholar and poke around for the citation history of loci implicated in cognitive performance variation.