This is leaving aside the issue of how problematic IQ tests are, especially when applied across cultural boundaries. I've seen "studies" which show the average IQ of sub-Saharan Africans to be below 70; this is patently ridiculous, as human societal function is impossible at this level. (By comparison, sign language trained chimps regularly score in the sixties and seventies.) People treat these studies as legitimate or illegitimate largely on the basis of their political positions on race.
I saw an interesting study lately involving standardized tests (not IQ tests, although it might have implications for IQ testing as well).
When questions on a standardized test were altered ("What does AFDC stand for?" "What are food stamps?" "What buses would one take to get downtown from Washington Avenue and South 2nd?") children below the poverty line aced it and children above the poverty line failed it miserably.
In fact, in response to the "food stamp" question, many affluent and middle-class suburban fourth graders guessed that food stamps were the stickers put on produce in the grocery store.
Obviously, standardized tests are not
that blatantly biased in favor of the affluent and middle-class, but they are
somewhat biased; they make reference to things a poor child might never have encountered or heard of, but that a middle-class child would be intimately familiar with.
When the tables were turned, poor children outmatched their more affluent peers handily.
From personal experience, I recall standardized tests being somewhat biased in favor of males; I remember many math questions, for instance, that involved sports and sports scores.
Such things are often far more interesting and familiar (and therefore understandable) to male children than to females, who might not even understand the rules or scoring of a particular game.
Of course there are girls interested in sports, and boys who aren't; there are poor children who are unfamiliar with public assistance and public transportation, and possibly even affluent children who
are familiar with them. But as far as generalities go, standardized testing is subtly biased in favor of middle-class/ affluent (ie, white) male suburbanites, and subtly biased
against females and the urban poor.
I would not be surprised if IQ tests were, too.