Friday, September 05, 2003


That intelligence is mostly hereditary has been the routine finding in psychological research on the subject for over a century but our “all men are equal” Leftists have fought that fact tooth and nail for many years now. To them, ideology must win, not evidence. They have come up with many stratagems to discredit the finding but the latest one is a lulu.

This story was pointed out to me by The Misanthropyst and I notice that Iain Murray and various others have referred to it as well. It claims that heredity is the main factor in determining white IQ but is NOT the main factor in determing black IQ! So are blacks a different species from whites, then? That would seem to be the conclusion if we took the study seriously.

Full publication of the study has not been done as yet but from what we know so far it seems that what they found was in fact much simpler than that. They found that if you separated out low income respondents (mostly black) and studied them alone, the role of heredity was less important in explaining IQ differences. That does sound like a real finding but it is in fact what statisticians would call a “restriction of range effect”. In other words, if you take ANY group and select out a subset that is relatively homogeneous with regard to some variable, differences in that variable will tend to have less importance in explaining other differences. Since socioeconomic status and race are substantially correlated with heritable IQ, that is precisely what these researchers have done: Selected a group that is relatively homogeneous in genetic inheritance for IQ and then said: “Hey! Differences in genetic inheritance are not so important here!” Statisticians would call the finding an “artifact” -- i.e. something created by the research procedure rather than a genuine finding about the world.

With or without such “findings”, however, it of course remains true that worrying about the genetic potential of blacks does nothing to help them. People surely do not need to be misled about blacks before they will support programs that really do help blacks to cope better with the world in which they live. Finding such programs is the real challenge.


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