Logo image
Judgments of visually perceived eye level (VPEL) in outdoor scenes: Effects of slope and height
Journal article   Peer reviewed

Judgments of visually perceived eye level (VPEL) in outdoor scenes: Effects of slope and height

R.P. O'Shea and H.E. Ross
Perception, Vol.36(8), pp.1168-1178
2007
url
Link to Published Version *Subscription may be requiredView

Abstract

When one looks up a hill from below, its peak appears lower than it is; when one looks at a hill across a valley from another peak, the peak of that hill appears higher than it is. These illusions have sometimes been explained by assuming that the subjective horizontal is assimilated to the nearby slope: when looking up a slope, the subjective horizontal is raised, diminishing the height of the peak above the subjective horizontal, and making the peak appear lower than it is. When looking down a slope towards another hill, the subjective horizontal is lowered, increasing the height of that hill above the subjective horizontal, and making its peak appear higher than it is. To determine subjective horizontals we measured visually perceived eye levels (VPELs) in 21 real-world scenes on a range of slopes. We found that VPEL indeed assimilates by about 40% to slopes between 7° downhill and 7° uphill. For larger uphill slopes up to 23°, VPEL asymptotes at about 4.5°. For larger downhill slopes, the assimilation of VPEL diminishes, and at 23° is raised by about 1°. These results are consistent with the assimilation explanation of the illusions if we assume that steep downhill slopes lose their effectiveness by being out of view. We also found that VPEL was raised when viewing from a height, in comparison with ground-level views, perhaps because the perceived slope increases with viewing height.

Details

UN Sustainable Development Goals (SDGs)

This output has contributed to the advancement of the following goals:

#3 Good Health and Well-Being

Source: InCites

Metrics

InCites Highlights

These are selected metrics from InCites Benchmarking & Analytics tool, related to this output

Collaboration types
Domestic collaboration
International collaboration
Citation topics
1 Clinical & Life Sciences
1.7 Neuroscanning
1.7.661 Saccades
Web Of Science research areas
Ophthalmology
Psychology
Psychology, Experimental
ESI research areas
Psychiatry/Psychology
Logo image