Todd Reed:
> I believe this thread is conflating 'smart' with the the underlying
> equipment. Paleo man had the same underlying biological structure,
> the mental infrastructure was inferior in terms of development and
> complexity. The software of language, culture and technological
> development. ...

Actually, I think William was saying that Paleo people had biologically,
rather than culturally, superior brainpower. Jared Diamond also was not
arguing that the New Guinea hunter gatherers were smarter in terms of
language, culture or technology, he was arguing that they have slightly
superior underlying biological structure than Europeans due to natural
selection. If his hypothesis is correct, the differences in mental
capabilities would likely be too small to legitimize the arguments of
racial/group brainpower superiority, but large enough to create a scientific
and political firestorm. I think his hypothesis is plausible, though I would
pose a different main mechanism (small overall average genetic benefits from
superior diet rather than selection for epidemic survival).

I'm guessing that other people who have adopted a Paleo diet have, like me,
noticed some improvement in mental clarity, memory, etc., upon doing so, at
least temporarily. The lectins and other harmful ingredients in modern foods
are essentially mild toxins that likely have negative effects on the brains
of developing fetuses (gluten has been connected with Down's Syndrome and
schizophrenia, for example). Generations of this toxin ingestion likely has
some negative impact on overall average societal brainpower. Whether it is
of a significant level or not is another question, depending in part on how
much brainpower difference one considers significant.

Ron Hoggan wrote:
<<I can't remember the source off hand, but pre-agriculural human skull size
has been shown to be somewhere around 10% larger than post-agricultural
humans. That suggests a larger brain size

But did all that size reduction occur after the development of agriculture,
or did the shrinkage begin before then?

I found this source in my files, but it doesn't mention when the shrinkage
occurred exactly:

HISTORY OF STONE AGE MAN 
http://www.historyworld.net/wrldhis/PlainTextHistories.asp?historyid=ab10

"The humans of Cro-Magnon, and their predecessors in other parts of the
world, are anatomically almost identical with people today. They differ in
being taller and more muscular; some of their skeletal remains reveal
(contrary to modern preconceptions) a larger brain than today's average."

Ron Hoggan:
<<Further, given the opioid and other psychoactive peptides from the
incomplete digests of gluten and dairy, imparied function of the modern
brain. Finally, the emerging recognition of neurological and autoimmune
damage caused by gluten, also suggests the possibility of impaired
intellectual function of moderns. Taken together, I think the notion of
devolution may have some validity. >>

Well said, Ron.