Tom, Some quick points.

* I am a liberal and I accept a genetic effect on cognitive abilty. I keep saying that but no-one listens.

* That 'statistical adjustment' for environment you refer to is the environmental effect on cognitive abilty.

* Cognitive ability has both genetic and environmental factors. IQ tests (so far) can not separate those for any individual. However, statistical methods and science has examined that question in terms of populations. The best estimates of those attempts so far attribute about a 50/50 contribution by genes and environment - although that could vary in any individual. Even hereditarians agree on this.

* That does not address the question of just what IQ is. I believe that a person's actual cognitive ability (both the innate and environmental components) is a complex variable that could not be expressed as a single number. IQ can be useful as a simple proxy for the complex concept of cognitive ability as long as people remember that - but they won't, of course.

* Even among the hereditarians there are three versions of the inherited IQ theory. The different brain structure model, the different information processing model, and the different intelligences model. The reality (for inherited cognitive ability) could well be some combination of those but all three are themelves plausibly subject to environmental effects during development.

* I accept that IQ predicts some forms of accomplishment. Like Binet I believe that IQ can be a useful tool to help identify children who may need special attention in school.

* Binet warned against and predicted that conservatives would sieze upon IQ as a way to justify unequal treatment of minorities. How right he was.

* If hereditarians agree that cognitive ability is a mix of inherited and environmental factors - and that Ashkinazim Jews can increase their IQ substantially in just a few generations - then why are they not demanding better environmental conditions for groups who test low on the IQ scale in order to eventually raise those scores and eliminate that drain on society for our descendents in future generations - instead of setting up special communities to house them.

Margaret