P3D eidetic and Pulfrich?

[Stuart Stiles <sstiles@xxxxxxx>]

> Date: Fri, 26 Dec 1997 13:29:26 -0600
> From: wier@xxxxxxxxxxxxxxxxx (Bob Wier)
> To: photo-3d@xxxxxxxxxxxxxxxxx
> Subject: P3D Re: eidetic and Pulfrich?
> Message-ID: <v01550104b0c9adb9bf77@[204.133.195.170]>

Response to John R.
> 
> >The problem with thinking of it as a memory model is that you could watch a
> >30-minute movie with continuous Pulfrich effect, and see stereo the whole
> >time. For the view from the eye with the dark lens, you would have to be
> >"storing" the view all that time without consciously seeing it, then
> >"recalling" it a fraction of a second later.
> >      We do Pulfrich Pendulum effect in the psychology course on a 
regular basis.  The primary effects are produced, according to Richard 
L. Gregory EYE AND BRAIN, is due to two phenomena... First, the dark 
adaptation process involves a "delay of messages from the retina to the 
brain," and "It seems that increased delay with dark adaptation is 
associated with increase in temporal integrating time - as when a 
photographer uses a longer exposure in dim light."  

The eye that is adapting to the darker image is shifting to rod vision. 
The eye that remains in full illumination utilizes cone vision.  Both 
sets of photoreceptors send visual information which is held in a 
fleeting eidetic sensory memory; all of the information requires brain 
integration, which also takes some time.  

Because you have introduced the fusion of images by which we detect 
motion in moving pictures and the fusion of retinal disparity images, 
this discussion is quite interesting.  We do have the ability to recall 
depth in our visual imagery.  The retrieval would be of the integrated 
moment of time when the image was perceived.  

To be able to retrieve one eye's image, in order to be able to add that 
disparity to the image of the other eye's view of the stereogram one 
hour later is quite remarkable!  To be able to continue the process 
while watching one side of a movie is more than challenging.



> One thing which wasn't mentioned in the article would be whether in non-RDS
> situations if the eidtic memory still functioned in stereo. That is,
> whether people could project and explore stored images in stereo (assuming
> they had originally viewed it that way) as opposed to flats..
> 

	I do not have the source at my fingertips, but there is 
cognitive psychology research that indicates that we have, as I 
previously asserted, the ability to remember in 3D.

> (Tangent - do people *dream* in stereo? I'm *pretty* sure I do, but am
> not 100% - I know for sure I dream in color)
> 	Thanks for a good topic of inquiry for my students!!  They love 
to talk about dream phenomena.


> >Pulfrich question: if you make a traditional 3D movie with polarized or LCS
> >glasses (instead of Pulfrich glasses), but display one view much darker than
> >the other one, does the Pulfrich effect still work? It seems to me it would,
> >but it would be interesting to hear whether it's actually been tried. 

> >John R

	Could one simply increase the density of one polarizing lens to 
test this hypothesis?

	Lots of good questions here.  

			Stuart


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