From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uunet!mcsun!uknet!edcastle!cam Sun May 31 19:04:02 EDT 1992
Article 5895 of comp.ai.philosophy:
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>From: cam@castle.ed.ac.uk (Chris Malcolm)
Newsgroups: comp.ai.philosophy
Subject: Re: Grounding: Real vs. Virtual (formerly "on meaning")
Keywords: symbol, analog, Turing Test, robotics
Message-ID: <21813@castle.ed.ac.uk>
Date: 25 May 92 17:12:12 GMT
References: <1992May22.152511.675@news.media.mit.edu> <ppyky7j.nagle@netcom.com> <1992May23.141738.14114@news.media.mit.edu>
Organization: Edinburgh University
Lines: 41

In article <1992May23.141738.14114@news.media.mit.edu> minsky@media.mit.edu (Marvin Minsky) writes:

>In "Society of Mind" I made a weak argument that humans have evolved
>to be especially helpless in infancy -- so that they're forced to
>learn more from their parents.

When proto-humans were subject to fierce evolutionary pressure to become
smarter -- and the speed with which our large brain evolved suggests
that this pressure was fierce -- it was not simply enough for the brain
to get bigger. Because if the brain got bigger, the head got bigger, and
if the head was too big there would be problems birthing it through the
female hips etc.. These problems would consist of the occasional death
of the child or mother, but more likely brain damage to the child due to
oxygen starvation during a protracted birth. Consequently the evolution
of bigger brains was a delicate balancing act. They would get bigger to
the point where the advantages of the bigger brain were offset by the
greater incidence of brain damage etc. during birth. Then any
improvement in female pelvis size etc. would release more effective
brain power, and permit the brain to get bigger until it ran up against
the new limits. 

Another way out of this pelvic bottleneck was to postpone more brain
growth until after birth. This also had the advantage of rendering the
brain more resistant to birth damage -- better able to repair it later.

This also had another side-effect which we have been able to exploit:
the more brain development is postponed until after birth, the more it
can be steered by experience -- such as language.

In other words, I suspect that while the human race has very likely made
considerable use of post-birth brain development, as suggested by
Minsky, that the evolutionary engine driving the development of that
possibility was the pelvic bottleneck.

[Biblical note -- after Adam and Eve had tasted Knowledge, God threw
them out of Eden, warning that birth thereafter would be painful.
Because they were now big-headed?]
-- 
Chris Malcolm    cam@uk.ac.ed.aifh          +44 (0)31 650 3085
Department of Artificial Intelligence,    Edinburgh University
5 Forrest Hill, Edinburgh, EH1 2QL, UK                DoD #205


