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From: jgk@osc.COM (Joe Keane)
Newsgroups: sci.bio
Subject: Re: do we perceive accelerations?
Summary: I think so.
Keywords: time-to-contact, constant velocity
Message-ID: <4853@osc.COM>
Date: 21 May 91 00:27:30 GMT
References: <1991May18.104301.17674@fwi.uva.nl>
Reply-To: jgk@osc.COM (Joe Keane)
Organization: Versant Object Technology, Menlo Park, CA
Lines: 22

My feeling is that acceleration is handled at a pretty low level.

Suppose you want to catch a baseball.  You have to decide where it's going to
go, and to do this you have to account for the effect of gravity.  In my
experience, this is done automatically by whatever tracking hardware is built
in.  From an evolutionary point of view, i think you can see that an animal
which didn't account for gravity would be at a disadvantage.

Another application is driving.  A useful skill is to be able to predict the
stopping position given my current velocity and deceleration, which is roughly
constant.  Or, given the current velocity and acceleration of my car relative
to the one in front of me, determine whether their positions will overlap at
some time in the future.  I find that these computations are done quickly and
accurately without conscious effort.

Now it's hard to say what of this is learned, as opposed to hard-wired and
instinctive.  Maybe we could raise some kids in zero gravity.  But it seems
reasonable to assume that these skills are important even to animals which
don't drive cars.
--
Joe Keane, amateur mathematician
jgk@osc.com (...!uunet!stratus!osc!jgk)