Aicm.v2

There has been a lot of talk lately, in the blogosphere at least (1, 2, 3, 4, 5), about the idea of using molecular genetics to predict and select for higher intelligence in humans (through pre-implantation screening of embryos, for example). The prevailing view among many discussing this idea seems to be that if we can do it, we obviously should do it. The casualness with which this conclusion is reached is astonishing to me, given the historyof humanity’s efforts in this area. To many commentators, it seems to be a given that having more intelligent people, across the population, is not only obviously a good thing, but one that supersedes any other considerations.

Selecting for increased intelligence doesn’t sound so bad, when you phrase it like that, until you realise that it actually involves the converse – selecting against individuals with lower predicted intelligence. I am not ascribing the following chain of thought to any particular persons, but here is the fundamental logic of eugenics, applied to intelligence:

For any individual, being more intelligent is better than being less intelligent. (All else being equal, that’s fair enough, I suppose). People who are more intelligent are therefore better than people who are less intelligent. (See how easy it is to get there?) At least, it would be good if we had more of the former and less of the latter. We should, as a society, seek ways to ensure that is the case. In the past, this would have involved policies on who is allowed to live or breed or migrate into a society, or inducements to get the more clever people to breed like they vote in Chicago – early and often. Nowadays, if we can employ pre-implantation genetic screening to predict intelligence, then we should use that method, or at least make it available, to select and implant those embryos that are predicted to be more intelligent. This will inevitably be at the expense of ones predicted to be less intelligent. The former should be granted life and the latter should not.

Is all that just self-evident? Is that how we should define progress in our society?

The amazing thing, in the pieces I have been reading recently, is that something approaching this position seems to have been reached not after lengthy and sober consideration of the moral and ethical issues surrounding the idea, but in total disregard for them. The following questions don’t seem to have come up: Is it right to claim some people are superior to others or of “higher quality”? Is it right to actively select between embryos (or to selectively abort foetuses) on any criterion? (Many people would say no, though it already happens routinely for serious medical conditions, and even for sex in many parts of the world). If there are some criteria that can be considered legitimate, what are they? How do we decide? Who makes those decisions? Should society as a whole ever have the right to dictate such decisions? Or should society allow complete freedom to individuals to make such decisions on any criteria they wish? If selection is permissible, is intelligence really the primary trait on which such selection should be based? What about kindness or decency or bravery or empathy or not being a douche? Do any of those get a look in? Would we lose anything from human society by selecting purely for those who perform better on IQ tests?

The impression one gets is that the people proposing such ideas think the world would be a better place if there were more people like them in it. The spectacle of cosseted academics bemoaning the degraded intellect of the masses and suggested something should be done about it is not an appealing one. And it is not without consequences.

There seems to be little recognition of the potential harm to the reputation of genetics as a science when it is associatedwith public claims of this sort. This discipline still bears the taint of previous misuses, most notably as justification for the murderous eugenic policies of Nazi Germany or enforced sterilisations of the “feeble-minded” in many US stateswhich ran from the early 1900’s to as late as 1977 in North Carolina. Many other countries enacted similar policies.

The themes of genetic classism and discrimination and of elitist scientists “playing God” resonate widely in our culture (from Shelley’s Frankensteinto GATTACA to the X-Men). Indeed, the extensive coverageof a study on the genetics of IQ that is currently underway at the Beijing Genomics Institute (BGI) suggests that the media knows a good story when it sees it. It seems to me that this has attracted attention not because of any scientific advance or discovery (the study has not yet been completed) but because of the way those involved and commenting on it have acted as cheerleaders for the idea of prenatal prediction and selection.

Here’s Prof. Geoffrey Miller (of NYU), in an interview for an article egregiously entitled “China is engineering genius babies” on vice.com (whatever that is):

“How does Western research in genetics compare to China’s?
We’re pretty far behind. We have the same technical capabilities, the same statistical capabilities to analyze the data, but they’re collecting the data on a much larger scale and seem to be capable of transforming the scientific findings into government policy and consumer genetic testing much more easily than we are. Technically and scientifically we could be doing this, but we’re not.”

Some would argue it is not the place of scientists to decide the ethical issues – it is our job just to do the science. If society abuses it, well, that is not our fault. This is a case where I strongly disagree – we cannot disentangle the moral issues from the scientific ones. It is too easy to use scientific findings to justify policies that would otherwise be deemed abhorrent; too easy, as Hume noted, to mistakenly derive a prescription of how things ought to be from a description of how they are.

In this case the science is too complex and our understanding still far too fragmentary to even describe how things are. But reading some of the commentaries one would think that our ability to predict intelligence based on molecular genetics is really just around the corner; that we will have this knowledge in hand within a few years and Pandora’s box will have been opened, whether we like it or not. I find this scenario highly implausible, for several reasons.

First, we have not yet identified any genes “for intelligence”. We know many that, when mutated, can cause intellectual disability (many hundreds, in fact), but none that clearly contribute to variation in the normal range (normal in the statistical sense of that word). Zero, zip, bupkis. We are starting from effectively complete ignorance as of this moment. In fact, we don’t even understand the genetic architecture of intelligence. It is clearly very highly heritable, but we don’t know how many genes are involved, either across the population or in any individual, we don’t know whether the genetic variants are common or rare, we don’t know whether they specifically affect intelligence or have more general effects on robustness of the genetic program and its execution to build an efficient brain and we don’t know how multiple such variants would interact with each other. That’s a lot of don’t knows.

The answers to those questions will determine the best strategies for finding variants that affect intelligence and also, crucially, our ability to predict an individual’sIQ based on signatures that we can only detect by averaging across the population. If we want to be fanciful, we can imagine a future scenario where we have in fact identified many genetic variants across the population that clearly contribute to differences in intelligence. Some may be common, but my expectation is that most would be quite rare. Now we want to look at some new individual’s DNA and predict their IQ based on that knowledge (or maybe look at two individuals and predict which one’s IQ will be higher, even if we can’t put a number on it).

Here are the problems: first, IQ is indeed highly heritable, but a lot of the variation across the population is non-genetic (at least 20-30%); that imposes a significant limit on accuracy of even a perfect genetic predictor. Second, if IQ is largely affected by rare mutations, then each new person will have some IQ-affecting variants that we have never seen before in our population sample and that we will be unable to recognise as such. Third, any individual will also have a unique, never-before-seen combination of variants, which may interact in highly unexpected ways. Finally, any such predictor would have to be extremely precise to distinguish between the IQ of not just any two random individuals, but two siblings, where the range will obviously be much narrower.

To paraphrase Yogi Berra, making predictions is hard, especially about the future. But I am willing to go out on a very sturdy limb and predict that we will not be able to build useful predictors for IQ any time soon. We’re not there, we’re not nearly there and there may even be fundamental limits that mean we will never get there.

In the meantime, before we go proposing scientifically impractical and morally questionable extreme measures, we have a proven and powerful tool to make people smarter: education.