The debate over racial differences in IQ represents perhaps the greatest scientific controversy of the past half-century. The facts are not in serious dispute: blacks score, on average, significantly lower than whites in IQ tests in the United States, Britain and beyond.
Some argue that the only plausible response is to accept that blacks are naturally less intelligent than whites, a view that causes outrage among equal rights campaigners. But is there an alternative explanation for these puzzling statistics and what would it mean if there were not?
All too often the liberal establishment has stifled debate on the issue by pretending that it does not exist. It is asserted, for example, that the concept of intelligence is culturally relative. Even if this is (relatively) true, it does not alter the fact that the kind of intelligence revealed by IQ tests is crucial to one’s prospects in the modern world. It hardly helps the cause of racial equality to argue that, although blacks do worse at IQ tests, they have the kind of intelligence that is useful in preindustrial societies.
The reluctance of liberals to engage in real debate has left the impression that there is an inconvenient truth about IQ differences that is being suppressed by political correctness. This has bolstered the phenomenon of black skin being used subconsciously as an information-bearing trait, so that blacks are judged as a group rather than as individuals. This has prejudiced blacks in finding jobs and amounts to de facto affirmative action for whites.
The unwillingness to engage with the IQ controversy is based upon the fear that an exclusively environmental explanation is difficult to sustain. It is generally accepted that the variation in IQ within the white population is largely heritable, as is the variation within the black population. But if white-white and black-black IQ differences are predominantly heritable, how could it be that the black-white difference is exclusively environmental? This argument was first put by Arthur Jensen in 1969 in his seminal paper, How Much Can We Boost IQ and Scholastic Achievement?
But it rests upon a confusion. To see how, imagine a sack of genetically diverse seed that is randomly divided into two bunches. Bunch A is grown in a field with good lighting and Bunch B in a field with poor lighting. The differences in height between the seedlings in Bunch A will be exclusively genetic since they have all been subjected to the same environment. The same is true of Bunch B. But the difference in the average height between Bunch A and Bunch B is exclusively environmental—caused by the difference in lighting conditions.
This tells us that the variation within two populations (such as whites and blacks) has no logical connection with the variation between populations. This insight is particularly powerful when combined with the research of James Flynn, a New Zealand psychologist who discovered that IQ scores are inflating over time, a phenomenon that can only be explained by environmental factors.
Flynn’s discovery provides a real example of the thought experiment involving the seeds: IQ variation within each generation is largely heritable; IQ variation between generations is exclusively environmental. For the environmental hypothesis to work, we need only show that today’s black Britons face comparable conditions to whites in the mid1950s, something that chimes with common sense and social data. Allied with evidence of how IQ differences disappear when black children are brought up in residential nurseries with white children, the environmental hypothesis becomes convincing.
This will not come as a surprise to geneticists who have long understood that racial categories are social constructs lacking genetically rigorous boundaries. Most genetic variation exists within groups rather than between them and skin colour can be a highly misleading measure of the genetic distance between populations. It would have been astonishing if the diverse peoples who happen to share darker skin all had a genetic IQ inferiority.
The environmental explanation for racial IQ differences might also come as a relief to whites, a group that scores lower than East Asians. The idea that whites are naturally inferior in IQ to East Asians is worth pursuing if only to observe the reaction of white supremacists. But, as Flynn has shown, the environmental explanation is as persuasive for the difference between whites and East Asians as between whites and blacks.
But need liberals have been so paranoid about the possibility of natural IQ differences between the so-called races? Let us suppose, for the sake of argument, that whites have a genetic advantage in IQ over blacks. Would this sanction the kind of policies favoured by the far Right, such as segregationist schooling or a bar on blacks entering university?
It is not difficult to spot the logical fallacy. Even if the average black had a naturally lower IQ than the average white this would not mean that all blacks had lower IQs than all whites. There would still be a significant overlap such that if a white person and a black person were chosen at random there would be a fair chance that the black would have a higher IQ. This demonstrates that even in a hypothetical society with genetically based racial differences in IQ it is sensible to treat people as individuals rather than as group members.
Of course, if the far Right were sincere in its motivation for the different treatment of blacks it has a far more effective policy at its disposal. Why not set a mandatory IQ test and then divide people into high, medium and low IQ? Anecdotal evidence suggests that a disproportionate number of the far Right would find themselves in the lowest category and ripe to be bossed around by intelligent black masters.
This ought to demonstrate to all shades of opinion that apartheid is an evil whether it is based upon colour, IQ or anything else. The fear of the Left over possible natural differences between the so-called races is understandable but exaggerated. It is founded upon the idea that political equality is derived from some actual equality that we all share. The truth is that political equality is a moral abstraction, not an empirical discovery. Grasping this important truth should enable us to celebrate our differences rather than cower in fear of them.