25 Sep 1995 09:55:55 GMT
Ralph L Holloway (firstname.lastname@example.org) sez:
`Whoa. It's pretty rare that female Australian Aboriginal brain
`endocasts get lower than about 900 ml, but it is true that on the
`average, Australian Aboriginal brain weights are somewhat lower than,
`say, Caucasian or Asian, at least from the data I've looked at.
`And there does appear to be some evidence for some "different" wiring
`in the Australian Aboriginal brain, in that their primary visual
`cortices (Brodmann's area 17) are relatively larger (and statistically
`significantly so) than for those of Caucasians.
The speculation I was referring to wasn't about australian brains,
but hominid brains in general. About a month or more back, someone
suggested here that intelligence in fact might have preceded increase
in brain size, due to a qualitative innovation in the structure
of hominid neural wiring. This would have been about 3 or 4 Mya.
The argument then went that the subsequent increase in brain size was to
provide redundancy for an organ that was now of primary importance.
According to this model, an australopithecus might be almost as
bright as ourselves, but would get dim faster with age and
consequent neural attrition. The corollary was that a human
level of intelligence would not require a full human brain weight.
The poster pointed to examples of hydroencephalics who achieve
normal intelligence while possessing large fluid filled voids
in their brains (I recall one featured on a tv program, possibly
email@example.com <== faster % Pete Vincent
firstname.lastname@example.org % Disclaimer: all I know I
% learned from reading Usenet.