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Visually perceived eye level is influenced identically by lines from erect and pitched planes
Perception
|January 1, 1996
Summary
Visual perception of eye level (VPEL) is influenced by line orientation in the visual field. Stimulus orientation on the retina, not depth, primarily affects VPEL in stationary observers.
Area of Science:
- Visual perception
- Psychophysics
- Neuroscience
Background:
- The physical elevation corresponding to eye level (VPEL) can change based on visual field orientation.
- Previous research indicates a significant influence of visual field pitch on VPEL, even with simple stimuli.
Purpose of the Study:
- To investigate how line orientation, specifically 'visual pitch', affects VPEL.
- To determine if retinal locus stimulation or the 3D orientation of a line stimulus is the primary driver of VPEL changes.
Main Methods:
- Subjects viewed visual fields with one or two lines at varying orientations in depth ('visual pitch') or oblique orientations.
- Experiments compared VPEL responses to pitched-from-vertical lines and oblique lines stimulating equivalent retinal loci.
- Stimulus sequencing and subject naivety were controlled in a third experiment.
Main Results:
- Both pitched-from-vertical and oblique line orientations systematically altered VPEL.
- The effects of pitched and oblique stimuli on VPEL were indistinguishable.
- No influence of stimulus sequencing or subject experience was found.
Conclusions:
- VPEL is primarily controlled by the retinal locus stimulated by a line, not its 3D orientation in depth.
- The orientation of the line's image on the retina is the key factor influencing VPEL for stationary observers.
- Findings support the great-circle model of visual perception.
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