🚀 go-pugleaf

ledwards@leland.Stanford.EDU (Laurence James Edwards) writes:

>Yes, the ability to catch things does not require "solution" of a DE 
>or set of DE's in the normal sense of the word, you just need a good
>feedback control system ... you may need to tweak the gains depending
>on what your catching (maybe adaptive feedback control is the more correct
>term) but to say that one must "solve" a complex set of DE's is misleading.

>|> Now throwing a projectile, and estimating its trajectory in advance during
>|> "get set", is indeed a good candidate for a cognitive mechanism.  All of
>|> the ballistic movements (kicking, clubbing, throwing, hammering -- even
>|> spitting) require lots of advance planning; feedback arrives too late to
>|> do any good, so "get set" must create a complete movement command
>|> sequence, start to finish.

>While throwing activities are better candidates for cognitive mechanisms
>I still don't think they *require* anything more than the ability to
>interpolate or extrapolate from past experience.

>Larry Edwards

Agreed.  What's so nice about throwing and the other ballistic movements
(hammering, kicking, clubbing, spitting) is that they may share a common
neural machinery for fancy sequences.  It is already known that the core
of language cortex (see the Ojemann article in 1983 Behavioral and Brain
Sciences) has a sequencing specialization, that it handles both auditory
sequences and movement production sequences.
	So it may be that evolutionary pressures for one sequencing task
bring along some of the others for free.  Certainly this hypothesis is
requires at some point for music and dance, i.e., they must be secondary
uses of neural machinery that was primarily shaped up by other kinds of
usefulness, such as language or planning ahead.  As I have proposed (THE
ASCENT OF MIND is the most recent version), any of these various skills
might have helped improved the others -- but precision throwing for
predation has a particularly nice payoff in terms of reproductive success
during hominid evolution.  That's why throwing is so interesting to one
interested in higher intellectual functions such as language and plan-ahead.
    William H. Calvin   WCalvin@U.Washington.edu
    University of Washington  NJ-15
    Seattle, Washington 98195 FAX:1-206-720-1989