P3D Re: Eidetikers

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Thu, 25 Dec 1997 16:19:01 -0700
>From: wier@xxxxxxxxxxxxxxxxx (Bob Wier)
>Subject: P3D Eidetikers

>[1970 article]
>It has to do with research on "photographic memory", where a few people
>can actually visualize an image and direct their attention to specifc
>areas and see detail unnoticed at the time or original viewing.

>There was some controversy as to whether eidetikers (as they are called)

Accent on the second syllable?

>could really effectively "project" an image into space and "read" it, or
>if they just had really good visual memories of a more traditional
>sort.

>An experiment was designed where test subjects were shown two sections
>of a 10,000 dot SIRDS image (each eye separately, separated by 24 hours). 
>One of the test subjects was able to "project" the images together and
>bring up the 3-D image (a floating square above the surface), whereas it
>had not been seen with the individual image(s).

I think investigations into perception are fascinating, particularly in
situations like this where there is a possibility that they will lead to a
new way of presenting 3D.

I can only speak from personal experience. I don't appear to have what others
describe as "photographic memory", but I can sometimes "play back" a series
of visual and other impressions that took place hours ago, or days, or even
longer, with such a level of clarity and detail that it almost seems like
watching a movie, or being there again. That ability is not necessarily
fully under conscious control (not to say it couldn't be developed to some
extent), and while it's possible to recover details that were not consciously
remembered before the "playback", most of the bandwidth of the recollection
is centered on the things I was paying attention to at the time. If I
had happened to glance at a sign with several dozen words written on it,
but didn't bother to read it at the time, then on playback I would remember
looking at the sign, and I might remember the font of the lettering, but I
wouldn't be able to "read" the words of the sign. Having not read much about
memory, I don't know what this kind of recall is called, but I would assume
many other people must have it.

(By a completely different mechanism, it's possible to "play back" a sentence
that was just spoken, even if one was not paying attention at the time -
a very handy ability to have when suddenly called upon in class! :-)

The idea of long-term visual memory brings up another interesting issue -
when you recall or imagine a visual image, where in the brain is it "played"?
One documentary I saw seemed to indicate that when data from the eyes first
reaches the brain, at least one destination is an area that actually
physically maps a visual image onto the surface tissues of the brain. Either
from there or as a parallel path from the eyes, the data goes to many
specialized processing structures that extract shapes, detect motion, do
image recognition, and so on. Some of these processing structures (not
necessarily just one) have to do with the extraction of depth information,
and the construction of a mental 3D model.

When you recall or imagine an image, is it "played" in the same place where
incoming data from the eyes is first played? If the people in the article
could truly reconstruct random dot stereograms from images viewed separately,
it would appear that they were able to replay their memories somewhere
before (in the processing sequence) the part of the brain that extracts
depth information from binocular disparity.

It's clearly possible to visualize one image while looking around in the
real world, so the brain in a sense is "looking" at two entirely different
images simultaneously. Is it possible to mentally picture two or three
images at the same time (not as side by side pictures, but each filling the
entire "field of view")? Does closing your eyes increase the number of
mental images that can be held simultaneously? Does specifically picturing
the mental images as 2D or stereo increase or decrease the image holding
capability?

I would appreciate it if some other people could comment on their thoughts
or experiences on these matters, or if anybody knows the current views of
the research community.

John R


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End of PHOTO-3D Digest 2476
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