P3D Re: Bowl and stereo lies

[roberts@xxxxxxxxxxxxxxxxx (John W Roberts)]

>Date: Thu, 8 Jan 1998 13:33:11 -0700
>From: "H a r o l d   B a i z e" <baize@xxxxxxxxxxxxx>
>Subject: P3D Bowl and stereo lies

>Here is the interesting part for me. I sometimes hand the viewer 
>to friends with the flat dinosaur slide, and say "Wow, look at 
>this 3-D slide!" So far not a single person has objected and said 
>that it is NOT 3-D. When I tell them it is flat they just seem dumbfounded. 

Perhaps some of them don't want to hurt your feelings, since you're obviously
excited. I would probably spend a while trying to think of a gentle way of
saying I didn't see much depth.

Actually, that highlights some of the limitations in some methods of
psychological research. When multiple factors are combined, and complex
human behavior is reduced to Boolean values, considerable information is
inevitably lost.

>Ok, I know it isn't nice to deceive people, but I was 
>trained as a social psychologist and old habits are hard to break.

Perhaps you're conditioning people to fear ridicule when they agree to
look at 3D images, in the manner that John Watson conditioned "little Albert"
to fear white, fuzzy objects in the famous rat experiment.

>The response of my "subjects" causes me to wonder whether people 
>are sincere when they praise the depth of stereo slides. 

There should also be cultural differences. Some cultures discourage direct
confrontation more than others.

>As a caveat I must admit that the flat dino photo has a lot of 
>non-stereoscopic depth cues, and to the uninitiated it may well 
>appear to have true stereo depth.

>Perhaps I should create another set of "flat" and "stereo" slides 
>where the image contains few or no depth cues. Perhaps a random 
>dot pair as in the classic Julesz studies.

How about showing them a 2D and a 3D version, then asking them whether they
detect a difference in depth? (A third slide with pseudoscopic mounting could 
be useful as well.) That way there wouldn't be deception, but still the
opportunity to tell whether they can discern the difference, and perhaps
present 3D in a positive light.

John R


------------------------------