Long-Standing Paradoxes in Visual Perception, which Purport to be Resolved by a "Global Stimulus" Theory of Perception
J. J. Gibson, Cornell University; 1957
The World Wide Web distribution of James Gibson's "Purple Perils" is for scholarly use with the understanding that Gibson did not intend them for publication. References to these essays must cite them explicitly as unpublished manuscripts. Copies may be circulated if this statement is included on each copy.
1. Why do we see only one subject when there are two retinal images or pictures of it? Why not two objects?
2. Why do we see the world right side up if the retinal image is upside down?
3. Why do we not see the world move when the retinal image moves across the retina as the eyes change their fixation?
4. Why do we not see a hole in the world (using one eye) corresponding to that part of the retinal image which is not registered by the retina (because of the gap in photoreceptors, i.e., the blind spot)?
5. Why do we see a world in three dimensions when the retinal images are in two dimensions? (Or is it that we do see a scene in two dimensions and only know it has a third dimension?)
6. Why do we perceive a rigid world if the retinal images stretch like rubber whenever we move about? Why a boundless environment if the retinal images are strictly bounded by the margins of the retina? Is this also a matter of acquired knowledge?
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