[photo-3d] Visual Cliff experiments (was Re: seeing 3-D: innate)

[Jim Crowell <jcrowell@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

> Anyway, does anyone know how the researchers performing the checkerboard
> pattern experiment prevented their human or animal subjects from perceiving
> distances through relative motion?  Most animals and babies don't hold their
> head perfectly still for very long.

These experiments (usually called the Visual Cliff experiments) were
originally done by the Gibsons at Cornell (by Eleanor Gibson, I think).
They were particularly interested in motion- and texture-related cues for
surface layout, which they considered to have been neglected in the study of
vision.  So they designed the apparatus to emphasize those cues, presenting
the babies with a large dropoff (so there'd be a lot of motion parallax) and
putting checks of equal size on the two levels, so the more distant ones
would project to a much smaller retinal size.

In other words, they deliberately designed the thing not to answer the
question we're interested in... :-)

-Jim C.

-------------------------------------
Jim Crowell, Ph.D.
Dept. of Psychology
Cognitive/Experimental Group
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Ohio State University
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