On Sun, 22 Nov 2009 12:12:12 -0800, "William Sommerwerck"
wrote:

Were the two groups of children controlled for family background? Those with
the higher lead might have been from lower-income communities with poorer
parenting.

Yep. That was exactly what I was mumbling.

I'll leave it to your imagination as to which of the 4 or so
"standard" IQ tests was used. Also, a 7 point (average or median?)
decrease doesn't mean much without also knowing the distribution.

Way back in college, I was part of an IQ study, or so I thought. We
were given the then standard Binet test in the morning. Another group
was given the same test in the late afternoon. About a week later, we
were informed that there was some kind of mistake and that all the
results were lost. The two groups took similar tests again, but this
time reversing the time of day that the tests were administered. This
was repeated at several other colleges.

The results were that almost everyone scored higher in the morning
than in the afternoon. The order of testing didn't matter. I don't
recall the exact numbers, but it was something like 5 to 10 points
higher. I've read about similar intelligence tests to estimate the
effects of stress, diet, assorted supplements, astrology, and peer
pressure. With a little practice, IQ scores can also be improved:
http://www.lumosity.com/k/improve-your-iq

Moral: There are plenty of other things, besides lead, that
significantly affect a persons IQ, that are also rather difficult to
control.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558