Men vs. women is the least of it. With other variables controlled, men and women in a population have the same mean IQ, but the dispersion differs. The female bell curve is slightly narrower, so women have fewer idiots and fewer geniuses among them. Where this gets touchy is that it may do a better job than cultural sexism of explaining why most of the highest achievers in most fields are male rather than female. Equal opportunity does not guarantee equal results, and a lot of feminist theory goes out the window.
But male/female differences are insignificant compared to the real hot potato: differences in the mean IQ of racial and ethnic groups. These differences are real and they are large enough to have severe impact in the real world. In previous blog entries I’ve mentioned the one-standard-deviation advantage of Ashkenazic Jews over gentile whites; that’s roughly fifteen points of IQ. Pacific-rim Asians (Chinese, Japanese, Koreans etc.) are also brighter on average by a comparable margin. So, oddly enough, are ethnic Scots — though not their close kin the Irish. Go figure…
And the part that, if you are a decent human being and not a racist bigot, you have been dreading: American blacks average a standard deviation lower in IQ than American whites at about 85. And it gets worse: the average IQ of African blacks is lower still, not far above what is considered the threshold of mental retardation in the U.S. And yes, it’s genetic; g seems to be about 85% heritable, and recent studies of effects like regression towards the mean suggest strongly that most of the heritability is DNA rather than nurturance effects.
For anyone who believe that racial equality is an important goal, this is absolutely horrible news. Which is why a lot of well-intentioned people refuse to look at these facts, and will attempt to shout down anyone who speaks them in public. There have been several occasions on which leading psychometricians have had their books canceled or withdrawn by publishers who found the actual scientific evidence about IQ so appalling that they refused to print it.
Unfortunately, denial of the facts doesn’t make them go away. Far from being meaningless, IQ may be the single most important statistic about human beings, in the precise sense that differences in g probably drive individual and social outcomes more than any other single measurable attribute of human beings.
Mean IQ differences do not justify making assumptions about any individual. There are African black geniuses and Ashkenazic Jewish morons; humanity and ethics demand that we meet each individual human being as an individual, without prejudice. At the same time, group differences have a significance too great to ignore. In the U.S., blacks are 12% of the population but commit 50% of violent crimes; can anyone honestly think this is unconnected to the fact that they average 15 points of IQ lower than the general population? That stupid people are more violent is a fact independent of skin color.
any intelligent solution to problems, also to social problems, starts with accepting the facts. Of course in this case we probably end up with a less intelligent but more “comfortable” solution. Like in many things in any society.