For the Halibut

[From Fred Nickols (980102.1750 EST)]

I was watching the evening news a few minutes ago when the scene shifted to
the Bronx Zoo. The newscaster was feeding halibut to sea lions. As I
watched, it dawned on me that the sea lions were providing a really good
example of "living control systems" in action.

What first caught my attention was that, as the newscaster was talking, one
of the zoo keepers tossed a halibut toward one of the sea lions. As the
halibut left the zoo keeper's hand, it was obvious to me that the toss would
be wide of the mark. It was obvious to the sea lion, too, for as soon as
the halibut left the zoo keeper's hand, the sea lion turned toward the
likely landing point of the halibut.

Next, the newscaster threw one toward the largest sea lion, a creature
called "Bandit." As soon as the halibut left the newscaster's hand, I knew
the toss was going to be long. So did Bandit, for he immediately turned
around and headed out toward the projected point of landing.

For lack of a better term, what I saw going on was "outfielder" or
"crack-of-the-bat" behavior. You know, how outfielders will, at the crack
of the bat (and presumably just a glimpse of the early part of the
trajectory), head in the proper direction to catch the ball just hit.

Two questions:

        1) How would a Skinnerian behaviorist explain what I witnessed?

        2) How would a PCT'er explain it?

P.S. The strange subject line owes to the newscaster's quip: "Why are we
here? For the halibut.
Regards,

Fred Nickols
The Distance Consulting Company
nickols@worldnet.att.net
http://home.att.net/~nickols/distance.html

[From Rick Marken (980106.1000)]

Wolfgang Zocher (980106.1420 MEZ) --

Rick, how did you model the retina? How did you model velocity-
detection in the retina?

...

As a first try, I solved some partial differential equations ....

My approach is (as you might imagine) VERY simple minded. I
am currently modeling the retina as a _one_ dimensional line.
The ball's projection on this retina (call it alpha) is the
arc tangent of the ratio of the ball's height above the horizon
to its distance from the retina (the retina is assumed to remain
vertical). The velocity of movement of the ball's projection on
the retina is just the difference between the value of alpha on
the current and previous program cycle. The "player" can control
this velocity variable only by moving toward or away from the
ball, thus varying the distance of the vertical retina from the
ball.

I haven't been spending a lot of time on this. Any suggestions,
code or whatever would be greatly appreciated.

Best

Rick

···

--
Richard S. Marken Phone or Fax: 310 474-0313
Life Learning Associates e-mail: rmarken@earthlink.net
http://home.earthlink.net/~rmarken