Did you even read my comment?

Answer this question:

> If you can’t study IQ how do you demonstrate that lead poisoning causes reduced intelligence?

The answer to that question should be blindingly obvious: you don't.

It should be clearly evident that trying to use IQ to establish that "<insert ethnic group here> are stupid" is bad science. It's the same sort of science to establish that "<insert environmental factor here> causes stupidity," so we also need to reject it even if the environmental factor is clearly something problematic. The problem isn't the conclusion, it's the methodology.

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sjducb 2 days ago | parent | next [-]

So do you reject that lead poisoning causes stupidity because it is unethical to measure intelligence?

It’s a good thing that measuring IQ enabled us to discover that trace amounts of lead in the environment causes reduced intelligence. That was a key piece of data for banning lead in fuel. The loss of IQ points happens to all kids living in cities, rich and poor. Rich powerful people didn’t want their kids made stupid by lead in the air.

I think that removing lead from paint and fuel has greatly improved the lives of billions of people.

	▲	vintermann 2 days ago \| parent [-]
		No, we knew lead was bad. We knew what heavy metal poisoning looked like, we knew lead caused heavy metal poisoning. We knew of a hell of a lot more concrete effects than average lower scores on IQ tests. > The loss of IQ points happens to all kids living in cities No, it didn't. The reduced test scores happened _on average_. I won't rule out that what you said is correct, in that it may well be the fear that "my child may lose 1-5 IQ points!" helped get lead banned, but if so, that's an indictment of society.

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tptacek 2 days ago | parent | prev [-]

I agree with half of this argument but think you're taking it too far when you reject IQ testing as an epidemiological tool. It's not dispositive. It's statistically ill fitted as a ranking tool, for the reasons you stated, and the fact that it's not reliable across its whole range, and test-test reliability issues, &c. But like, "you can use it as an indicator for environmental causes of cognitive harm" is actually a valid argument, I think?