Related Experiment Videos
Investigation of visual space using an exocentric pointing task.
R H Cuijpers1, A M Kappers, J J Koenderink
1Helmholtz Instituut, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
Perception & Psychophysics
|January 5, 2001
Summary
Visual space perception is anisotropic and not strictly metric, as shown by exocentric pointing tasks. Stereopsis improves spatial consistency but not accuracy in distance and orientation judgments.
Area of Science:
- Visual perception
- Psychophysics
- Spatial cognition
Background:
- The metric representation of visual space is a long-standing assumption.
- This assumption has lacked empirical testing, especially in naturalistic outdoor environments.
- Existing models conflict with outdoor measurements influenced by abundant monocular cues.
Purpose of the Study:
- To empirically investigate the structure of visual space.
- To test the metric assumption of visual space using exocentric pointing.
- To determine the influence of orientation and distance on spatial judgments.
Main Methods:
- Two experiments using an exocentric pointing task were conducted.
- Experiment 1 varied pointer-target separation and stimulus orientation (monocularly and binocularly).
- Experiment 2 manipulated relative distances of pointer and target (monocularly and binocularly).
Main Results:
- Visual space was found to be anisotropic, with deviations depending linearly on orientation.
- Left/right symmetry was maintained in median plane configurations.
- Stereopsis significantly impacted results, showing large deviations from veridicality in both monocular and binocular conditions.
- Relative distance was the primary parameter influencing perception (1-5m), requiring expanding and compressing functions.
- Binocular conditions showed greater consistency but persistent systematic mispointings.
Conclusions:
- The metric model of visual space is insufficient.
- Visual space perception is anisotropic.
- Stereopsis enhances spatial perception consistency but does not guarantee veridicality.