You will recall that when Joseph Fagan tested the speed with which infants could absorb visual information, he had an excellent idea of how smart they would seem as seven-year-olds. But Fagan's test had an advantage over the more traditional scores. Whereas IQ tests seemed to favor certain ethnic and racial groups, Fagan's test did not. Some babies were quicker to turn their attention from one picture to another, but there were no differences as a function of what racial group a baby belonged to. This stands in stark contrast to the persistent finding that the average IQ score of a group of black children is almost always lower than the average IQ score of a group of white children. Keep in mind that the overall correlation between Fagan's test in infancy and more traditional IQ scores when the children were older was high. Yet the correlation did not hold up for all of the children. Either some of the white children were doing better as they got older, or some of the black children were doing worse as they got older, hence the group differences among older children, where none was found in infancy. What might explain this confusing pattern?
We're beginning to find out why the IQ test might be a weaker measure of intelligence for black children than it is for white children. In the past ten years or so, psychologists have learned something very important about what might depress the IQ scores of some students and how to remedy it. The gap between the average score of a group of black students and the average score of a group of white students has diminished somewhat in recent years. But it hasn't gone away or even halved. There are only two explanations for this, broadly speaking. The one promoted by Charles Murray and Richard Herrnstein in their book The Bell Curve is that underlying differences in ability account for the gap, and nothing will change that. But many psychologists (as well as geneticists) doubt this explanation, not simply because it is politically and socially distasteful but rather because it represents bad science. To begin with, we know next to nothing, so far, about the genetic underpinnings of intelligence. Intelligence might well be the expression of a cluster of abilities and skills caused by a wide variety of genes, rather than a single attribute determined by a single gene. Second, we know very little about the relationship between the genetic basis of race and intelligence. In other words, even though skin color is inherited and IQ also seems to a great extent to be inherited, those two facts tell us nothing about whether intelligence and skin color have any underlying genetic relationship. The difference in IQ between racial groups might be a result of something altogether different. This point is so important and so often misunderstood that it is worth illustrating with a few examples.