Path: utzoo!attcan!uunet!mcsun!ukc!edcastle!aipna!cam
From: cam@aipna.ed.ac.uk (Chris Malcolm)
Newsgroups: comp.ai.philosophy
Subject: Re: AI - the real problem
Message-ID: <4083@aipna.ed.ac.uk>
Date: 1 Mar 91 18:27:27 GMT
References: <1473@ucl-cs.uucp>
Reply-To: cam@aipna.ed.ac.uk (Chris Malcolm)
Organization: Dept of AI, Edinburgh University, UK.
Lines: 38

In article <1473@ucl-cs.uucp> G.Joly@cs.ucl.ac.uk (Gordon Joly) writes:

>If the first people walked that Earth 2.5 million years ago, then why
>did they have a brain with the same biology of that of Einstein,
>Beethoven or us?

With a much poorer cultural inheritance (far less giants to stand on the
shoulders of) it took an Einstein to invent such things as the
bow-and-arrow and a Marie Curie to invent such things as the basket --
the basket has been cited as the single most important human invention.

Don't forget that the evolution of the human brain size has to run
parallel with the evolution of the female hips. In other words, our
brain size is a compromise between the advantages of a big brain, and
the disadvantages of the brain damage that afflicts at least some due
the difficulty of getting the big head out. Brains would keep getting
bigger until the effects of the hip bottleneck nullified the advantage.
The next increment in cleverness would then be produced by wider or more
flexible female hips, and the cycle would begin again.  And a social
culture-passing animal doesn't need _everyone_ to be smart, just enough
smart people to make the tribe and the culture smart. Culture is a
wonderful way of sharing out the mental talents of the few.  Under these
various circs you'd expect wide variation in smartness, partly due to
wide variation in genetic endowment, and partly due to the fact that
many (most?) people suffer from minor early brain damage.

The hip argument is just the most obvious example of a general truth:
that when there is strong selective pressure for some change (and the
rate of evolution of human brain size suggests there was), then it will
be achieved along with damaging adaptive stress to the rest of the
physiology. Once the selected-for change has stabilised, evolution will
then work "invisibly" to remove the adaptive stress by bringing the rest
of the genetic spec into line with it. The suggestion is that the big
brain hasn't been around for long enough for this to have happened yet.
-- 
Chris Malcolm    cam@uk.ac.ed.aipna   +44 (0)31 667 1011 x2550
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205