🚀 go-pugleaf

m23364@mwunix (James Meritt) writes:

>Bad example.  Catching a branch after a free-fall requires the
>"unconscious" solution of a DE.  Catching a ball is a complicated
>set of equations.  Now, being able to express it AS equations is recent,
>but the ability to solve them isn't....

All animals seem to have the ability to make at least one particular kind
of trajectory calculation, also involved in catching a ball:  that of
judging whether an approaching object will hit their head.  It produces
the blink replex, and cognitive-level abilities need not be invoked (it's
a brainstem-level reflex, based on looming).

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.  In the case of throwing to a target (as
opposed to threat throws, where accuracy is not important), precision
timing becomes very important: hitting a rabbit-sized target from the
length of a car requires getting the projectile release within a 5
millisecond launch window.

I've discussed this at some length, as a candidate for the sequencing
abilities that separate humans from apes, in various of my books, most
recently in chapters 7 and 8 of THE ASCENT OF MIND (Bantam 1990).
    William H. Calvin   WCalvin@U.Washington.edu
    University of Washington  NJ-15
    Psychiatry & Behavioral Sciences
    Seattle, Washington 98195 FAX:1-206-720-1989