when a geneticist tackles intelligence, badly

November 21, 2012 — Leave a comment


According to a widely reported paper by accomplished molecular geneticist Jerry Crabtree, the human species is getting ever less intelligent because our society removed the selective drives to nurture intelligence and get rid of mutations that can make us dumber. This is not a new idea by any means, in fact it’s been a science fiction trope for many years and had it’s own movie to remind us of the gloom and doom that awaits us if we don’t hit the books: Idiocracy. Crabtree’s addition to it revolves around some 5,000 genes he identified as playing a role in intelligence by analyzing the genetic roots of certain types of mental retardation. Then, he posits that because we tend to live in large, generally supportive communities, we don’t have to be very smart to get to a reproductive age and have plenty of offspring. Should mutations that make us duller rear their ugly heads in the next few thousand years, there’s no selective pressure to weed them out because the now dumber future humans will still be able to survive and reproduce.

Evolution does have its downsides, true, but Crabtree ignores two major issues with his idea of humanity’s evolutionary trajectory. The first is that he ignores beneficial mutations and that just two or three negative mutations won’t necessarily stunt our brains. Geneticists who reviewed his paper and decided to comment say that Crabtree’s gloom and doom just isn’t warranted by the evidence he presents, and that his statistical analysis leaves a lot to be desired. The second big issue, one that I haven’t yet seen addressed, is that Crabtree doesn’t seem to have any working definition of intelligence. These are not the days of eugenicists deluding themselves about their genetic superiority to all life on Earth and most scientifically literate people know that survival of the fittest wasn’t Darwin’s description of natural selection, but a catchphrase created by Herbert Spencer. Natural selection is the survival of the good enough in a particular environment, so we could well argue that as long as we’re smart enough to survive and reproduce, we’re fine.

This means that Crabtree’s description of us being intellectual inferiors of our ancient ancestors is at best, irrelevant and at worst pointless. However, it’s also very telling because it fits so well with the typical assessment of modern societies by eugenicists. They look at the great names in history, both scientific and creative, and wonder where our geniuses are. But they forget that we do have plenty of modern polymaths and brilliant scientists and that in Newton’s day, the typical person was illiterate and had no idea that there was such a thing as gravity or optics and really couldn’t be bothered to give less of a damn. Also, how do we define genius anyway? With an IQ test? We know those only measure certain pattern recognition and logic skills and anyone could learn how to score highly on them with enough practice. You can practice test your way to be the next Mensa member so you can talk about being in Mensa and how high your IQ scores were, which in my experience tend to be the predominant activities of Mensa members. But they are members of an organization created to guide us dullards to a better tomorrow after all…

But if IQ scores are a woefully incomplete measure of intelligence, what isn’t? Depends on who’s doing the measuring and by what metric. One of the most commonly cited factoids from those in agreement with Crabtree is how much time is being spent on Facebook an watching reality TV instead of reading the classics and inventing warp drives or whatnot. But is what we usually tend to call book smarts necessary for survival? What we consider to be trivial knowledge for children today was once considered the realm of brilliant, highly educated nobles. Wouldn’t that make us smarter than our ancestors because we’ve been able to parse the knowledge they accumulated to find the most useful and important theories and ideas, disseminate them to billions, and make things they couldn’t have even imagined in their day? How would Aristotle react to a computer? What would Hannibal think of a GPS? Would the deleterious genetic changes Crabtree sees as an unwelcome probability hamper our ability to run a society, and if so, how?

Without knowing how he views intelligence and how he measures it, all we have is an ominous warning and one that single-mindedly focuses only on potential negatives rather than entertain potential positives alongside them, and making conclusions about their impact on a somewhat nebulous concept which isn’t defined enough to support such conclusions. In fact, the jury is still out on how much intelligence is nature and how much is nurture, especially when we consider a number of failed experiments with designer babies who were supposed to be born geniuses. We can look at families of people considered to be very intelligent and note that they tend to have smart kids. But are the kids smart because their parents are smart or because they’re driven to learn by parents who greatly value academics? We don’t know, but to evolution, all that matters is that these kids secure a mate and reproduce. To look for selection’s role beyond that seems more like an exercise in confirmation bias than a scientific investigation into the origins of human intelligence. That research is much more complex and elaborate than gene counting…