Into the Trackless Swamp

Kevin drum ventures into the IQ Swamps. His post was inspired by Fred Kaplan's Slate piece GI Schmo on the dumbing down of the Army:

The bad news is twofold. First, the number of Category IV recruits is starting to skyrocket. Second, a new study compellingly demonstrates that, in all realms of military activity, intelligence does matter. Smarter soldiers and units perform their tasks better; dumber ones do theirs worse.

Category IV is the 10-30 percentile on the Armed Forces Qualifying Test - mainly an IQ test. (Kevin incorrectly calls it the bottom third.)

Kevin knows the risks, but decides to step into the swamp anyway:

Of course, we all know what the real problem is here: in contemporary discourse intelligence is inextricably bound up with race, which is why it's almost impossible to talk honestly about it. For that we mainly have conservative race demagogues like Charles Murray and Steve Sailer to blame — although liberals themselves haven't been entirely blameless either when it comes to demagoging IQ.

Fortunately, our intrepid hero (my second favorite blogger, btw) thinks he knows what to do about it:

In any case, I've long had a suspicion that one of the reasons IQ is so overvalued in our society — it's important, but it's not that important — is because it's one of the few cognitive traits that's routinely measured. Simply because it's something that most of us can put a number to, it becomes a de facto stand-in for all cognitive abilities, even though it very clearly isn't.

The answer? How about more testing, not less? Cognitive traits like sociability, empathy, self-discipline, and extroversion, just to name a few, are as important in contemporary society as IQ, but most of us have only a vague idea of how we compare to other people in these areas. If we routinely measured these things in addition to IQ, perhaps the lay public would start treating IQ as just one of many important cognitive traits and we'd all start to assign it an importance more in keeping with its true worth. This in turn might help to reduce IQ as the cultural flashpoint

More testing! That surely is the way to go! After, everybody's got to be good at something, right? Right?

Let's pass over the miscelleaneous unproven slam at Murray and Sailer - I know little of Murray and less of Sailer. Let them defend themselves.

Unfortunately, Kevin still gets a lot wrong: I've long had a suspicion that one of the reasons IQ is so overvalued in our society — it's important, but it's not that important — is because it's one of the few cognitive traits that's routinely measured. he says. This idea that IQ testing is just a bad habit is dead wrong. As one of Kevin's commenters mentions, IQ gets tested a lot because (1) it's easy and repeatable and (2) it's strongly correlated with performance in almost every activity. The NFL doesn't test prospective recruits IQ because it's customary, it tests them because they know that certain minimums are needed to perform - and they have a very good idea what those minimums are for every position. Kaplan's story just told him that smarter recruits even shoot straighter than their lower IQ fellows.

The same commenter, BRussell, also points out that the other traits Kevin mentions don't have those two useful characteristics: They aren't predictive, and different tests don't correlate well.

Another commenter, TangoMan, has some intriguing data purportedly correlating low IQ populations with inbreeding in the form of first cousin marriages. It's not a crazy idea. All of us are packing a dozen or two deleterious recessive genes. It's well known that sibling matings produce a very high proportion of severely handicapped offspring. The odds are about four times better for first cousins (we share 1/8 of our DNA instead of 1/2), but still might be bad enough to make for some marginally damaging recessive pairs.

Kevin writes a liberal blog, so most of the grief he has taken so far comes from the outraged liberals. The Nazi racists are out there too though - that's why the swamp is so dismal. I doubt that the conditions are ripe yet for discussing IQ rationally.