Compression of visual space in natural scenes and in their photographic counterparts.

Classical theories of space perception posit continuous distortions of subjective space. These stand in contrast to the quantitatively and qualitatively different distortions experienced in space that is represented pictorially. We challenge several aspects of these theories. Comparing real-world objects with depictions of the same objects, we investigated to what extent distortions are introduced by the photographic medium. Corners of irregularly shaped buildings had to be judged in terms of the vertical dihedral angles subtended by two adjacent walls. Across all conditions, a robust effect of viewing distance was found: Building corners appear to flatten out with distance. Moreover, depictions of corners produce remarkably similar results and should not receive a different theoretical treatment than do real-world scenes. The flattening of vertical angles cannot be explained by a linear distortion of the entire visual space. We suggest that, for natural scenes, compression of space is local and dependent on contextual information.