Suppose you wanted to believe, as I do, that intelligence and vague ‘racial groups’ are, on the whole, unrelated from a long-run perspective. What would you then have to believe about genetics and IQ, as well as the long-run effects of socio-economic circumstances on IQ to rationalise the overwhelming evidence that there is a strong correlation between IQ and ‘race’? That evidence is extensively discussed in this excellent blog by Ken Parish, alluded to in several references on this wikipedia page into IQ heritability, and pushed hard in this book I co-reviewed recently? I will argue in the below that the main thing you must then dismiss is the hypothesis that a strong correlation between the outcomes befalling identical twins ‘demonstrates’ the importance of shared genes. In turn, that forces you to re-evaluate a lot of medical and biological studies in many other fields.
Consider the basic evidence that the ‘Bell Curve’ adherents have to argue their case: they argue that starting from the darkest places in Africa with IQs around 75 you move away from the equator and see an increase in both wealth and IQ, passing over the US with an IQ of 100, ending up with Japan and South Korea where average IQs are around 110 and health and wealth are concomitantly high. Within rich countries too, the basic empirical relation is that the whiter the ethnic group, the higher the IQ scores. And everything that is desirable is positively related with IQ, including length of life, wealth, low crime, etc. The ‘Bell Curve’ adherents point to all these correlations and say they are causal and that, furthermore, there is a genetic component to IQ since IQ is strongly heritable within families: the IQ of identical twins who were separated at birth turns out to be pretty close, usually taken as evidence of genetic causality.
So the mountain to climb is to rationalise all those correlations without buying into genetic causality at the level of ethnic groups, loosely labelled as ‘race’. Find below my best efforts, allowing for the fact that I am of course mainly a consumer of this literature, not a fully up-skilled producer!
The simplest put-down is to say that IQ is not intelligence but measures a culturally-specific skill that, quite naturally, would be higher in countries oriented towards teaching those skills and valuing them. This put-down can be further motivated by saying that IQ is really just defined by its measurement, and is thus defined as ‘the skills that predict school scores’, which does not by necessity capture anything that is fixed for a person or that is independent of culture. Indeed, it is basically impossible to measure intelligence free of culture since from our very earliest days we direct our learning towards that which is valued by our surroundings. Education is similarly not intended to be free of culture and so the thing that predicts it will also not be free of it. So the first put-down is that intelligence cannot be measured free of culture and hence that comparing across ethnicities or racial groups is impossible to start with.
This put-down, which you see a lot, is not really sustainable. For one, the notion of ‘intelligence free of culture’ is a form of ‘humans without humanity’: a contradiction in terms. Hence intelligence is also specific to cultures, meaning that there is no such thing as ‘equal intelligence outside cultures’ either, so whilst it is true that IQ measures ‘ability to do tests valued in the rich world’ , that does not mean that one cannot talk about the heritability of being able to do those ‘Western schooling calibrated tests’.
Moreover, it turns out that high IQ in one culture does not translate into low IQ in another, a point also pushed by the very politically-correct James Flynn in his recent book: people with higher IQs on average are better and can more quickly learn almost every mental task you want to throw at them. So IQ might be specific to a particular test but someone who is 30 points ahead in IQ probably beats someone else at their own mental game as well. Worse, ethnic groups and species with higher IQs do on average seem to have bigger brains, as you would expect. It really is hard to believe that bigger brains do not mean one is smarter on average (accounting for body size). Worst of all, even in societies where one can argue that there are no major current cultural differences between groups, such as the various groups that have lived in the US for over 100 years and that hence now all speak English and have been to school for 3 generations, still show these strong average IQ differences between the ethnic groups.
A similar unconvincing put-down is to say that IQ cannot possibly have causal effects on wealth, crime, etc. because other things than intelligence cause those. Simply by the fact that IQ is the ‘thing that predicts education’ one would thus have to argue that education has no causal effect on wealth, health, crime, etc., because higher IQ on average does cause better education (the higher your IQ the further you can rise through the stages of education). The put-down needs an extreme version of the ‘screening hypothesis’ and would imply that around the world governments are wasting enormous amounts of resources into education without overall pay-off. You now and then get the odd economist arguing it but not without blushing. So if we accept that education is good for you then IQ is also good for you and not having it is bad for you.
So the usual cheap shots at the Bell Curve idea are not sustainable, unfortunately.
A more promising avenue is to see IQ as itself the outcome of a process of investments and that the same investments also cause bigger brains and would help with health, income, etc. This is what Flynn is trying to say. Effectively one can argue that IQ is like being able to drive cars: you need to be rich to have a car, having a car makes you even richer, and it helps if your parents had a car for you to practise on, but this does not imply there is anything genetic about car-driving abilities at the level of racial groups.
Consider all the things you then need to buy into however. For one, you must then argue that those countries with low IQ, brain size, and wealth, are in that position by virtue of some set of historical circumstances that have less afflicted the ones further away from the equator. Plenty of historical stories that give this, so that might be doable but it still needs to be proven. Second, you must then argue that there are strong lock-in effects that make a low IQ-Wealth-Brain equilibrium very stable so that a few generations of wealth increase do not suffice to escape. Third, you must buy into the notion that the individuals who migrated (as slaves or otherwise) were so disadvantaged by their initial low IQ that neither they nor the ensuing generations really managed to escape the relative disadvantage.
Consider this last point more carefully: to rationalise that even for communities that have lived in other countries for generations IQ is still lower and that IQ does correlate strongly between the generations, one must buy into the notion that kids will already very early on have acquired some of the lower IQ from their parents. Indeed, considering the high degree of correlation between separated twins, one must buy into the notion that the womb itself is a place where a lot of the disadvantages of the mother get conveyed onto the children before they are born.
There are mechanisms that fit this kind of hypothesis, including the notion that a wealthy and well-fed mother makes a better womb. Also there is the idea that genes can be turned ‘on’ and ‘off’ depending on circumstances and that genes get passed on set in an ‘on’ or ‘off’ stage. The finding that identical twins are much more similar than non-identical twins could then be due to a shared epigenetics: the identical twins’ on-off switches are synchronised in the womb, whilst this does not hold for the on-off switches of the non-identical twins for whom the same womb produces a different epigenetic effect. I have no idea as to the nitty-gritty of this, but can see how it might happen in principle.
If this is true then initial disadvantages between ethnic groups would then still get washed out as accidental ‘on-off’ switches occur each generation, but would disappear over the course of centuries. For any two or three generations you would then still see a lot of persistence in low IQ and its associated outcomes, but no true long-run genetic causality. To buy into this kind of story means one rejects the notion that heritability inevitably means genetic causality, something that would mean large changes in how genetic effects are inferred throughout the social sciences.
A great example of just the kind of mechanism we would be thinking of is given by height, which is quite heritable. People nowadays are much taller on average than they were in centuries gone past and the amazing thing is that the increase has been quite gradual for several generations, even though a lot of the most obvious ‘benefits of civilisation’ were achieved early on. Thus, at the start of the European height boom in the 19th century, people were perhaps a feet smaller than now but you saw the advent of better hygiene and the demise of infectious diseases. So the first generation was a bit taller. With better nutrition, less hard work and less other sick people to infect the general population, the next generation again was taller. This meant better wombs and richer parents for yet another generation who were fed and looked after even better. We are now talking about the 1930s when families were still huge and hence one couldn’t argue that life was easy yet. Yet, 3 generations on from that one and the Europeans are still getting taller, even in places where they have been traditionally tall already, such as the Netherlands and Scandinavia.
The story of height is hence very much one of an obvious co-movement of increases in health, wealth, and inputs into the next generations. And you can still see very short and very white people in Northern India where the genetic background to the Indo-Europeans is similar but wealth and health are still at the bottom of the scales, which translates into low IQs (and small brains).
The implications of this thinking go further though than just buying into the notion of quite persistent effects that take generations to wash out: it leads to the thought that there is (almost) nothing genetic about IQ at all, even within societies.
That kind of radical counterpoint comes with its own questions though. If there is no long-run genetic marker for intelligence, where does IQ variation within societies come from?
Some would come from the economic position of the parents, ensuring that wealth and health advantages that might be accidentally obtained in one generations get passed on (well-fed wombs again, but also the ongoing effects of being in a confident and positive environment on the ongoing development of the brain). Yet, if that were the only source of variation then societies and families should diverge as advantages get accumulated. This is not the case, because in general the next generation reverts back to the population mean, showing that there must be a strong other source of variation such that the persistence effects of parents helping their young ones are ineffectual against a long-run regression-to-the-mean force because of this ‘other’ source of variation.
What could this wealth-independent source of variation be? Perhaps it is as simple as the embryo and the young baby being lucky enough to get just enough and not too much of everything. A little bit how young sapling trees get to be tall because of accidental circumstances in the forest (more light available and the demise of competitors), so too could it be true that minute differences in the womb and very early childhood could ‘deliver’ very smart and not-so-smart new humans. And the ‘just enough’ factor matters: too much water or sunshine kills off the sapling just as much as too little and when there is the presence of other trees, streams, and other ‘genetically unforeseeable’ circumstances, there is no way to guarantee that the sapling will be ‘most fit’ for each circumstance, meaning that even the ‘perfect tree gene’ needs to be in the lucky position of having a ‘perfect accident’ of adjacent trees, water, etc. So too could it be with humans and intelligence due to accidents in the womb, the very process of egg fertilisation, and very early on in childhood: if intelligence is the outcome of many finely-tuned circumstances which are not under full control and of which the womb can only ‘make an educated guess’ from an ex-ante genetic point of view then more or less accidental circumstances will lead to a large variation in the intelligence of the young kid.
So, if you want, like I do, to hope that IQ and race are truly not causally linked via a genetic and thus somewhat unalterable mechanism, then you will find yourself nudging towards accepting a quite strong version of class-theory (many current disadvantages are perpetuated by the investments of the previous generation), the rejection of heritability as an indicator of genetic causality, willing to accept that there is almost no genetic cause of IQ even within populations, and wondering what the complex underlying source of variation in intelligence really is. That kind of thinking puts you outside of the mindset of most of the biologists and medics working on this, who are wedded to the genetic paradigm and who thus have only a minimalist sophistry standing between them and the Bell Curve …