🚀 go-pugleaf

[From Rick Marken (990421.2230)]

Oops.

I said [Rick Marken (990421.2130)]:

> We know from the optics of the situation that FoE will remain
> the same (on target) with the prisms on as long as the subject
> moves toward the actual target (as Rushton et al noted) or
> toward the _image_ of the target (as Bill Powers noted).

This is ridiculous. It implies two simultaneous FoEs. I think
Rushton et al are right and Bill is wrong; when you move to the
_actual_ target with prisms on, the FoE is where it was when the
prisms were off -- centered on the target (though displaced on
the eye). If you move toward the _image_ of the target (so the
image is foveaed) the FoE is _not_ centered on the target as it
is when the prisms are off. So I agree with Isaac and Rushton et
al: the fact that the subjets do not walk directly toward the
actual target suggests that they are _not_ controlling FoE, keeping
it on target.

I still think that the Rushton et al study doesn't constitute a
test of what variables people _do_ control when they walk to
targets. There is no evidence that FoE _or_ target image position
is under control in this study. In fact, I think it's likely that
_both_ of these variables are controlled when people walk to targets;
the subjects just couldn't control them right away given the rather
overwhelming change in the feedback function (connecting locomotion
to FoE and target image position) imposed by the prisms.

Of course, this is just my current point of view and anyone
can prove me wrong by having a differnet one;-)

Best

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