Convexity Bias and Perspective Cues in the Reverse-Perspective Illusion

Joshua J Dobias; Thomas V Papathomas; Vanja M Vlajnic

doi:10.1177/2041669516631698

Convexity Bias and Perspective Cues in the Reverse-Perspective Illusion

Iperception. 2016 Feb 29;7(1):2041669516631698. doi: 10.1177/2041669516631698. eCollection 2016 Jan-Feb.

Authors

Joshua J Dobias¹, Thomas V Papathomas², Vanja M Vlajnic³

Affiliations

¹ Department of Psychology and Counseling, Marywood University, Scranton, PA, USA.
² Department of Biomedical Engineering and Laboratory of Vision Research, Rutgers University, Piscataway, NJ, USA.
³ Department of Statistics, The Pennsylvania State University, University Park, PA, USA.

Abstract

The present experiment was designed to examine the roles of painted linear perspective cues, and the convexity bias that are known to influence human observers' perception of three-dimensional (3D) objects and scenes. Reverse-perspective stimuli were used to elicit a depth-inversion illusion, in which far points on the stimulus appear to be closer than near points and vice versa, with a 2 (Type of stimulus) × 2 (Fixation mark position) design. To study perspective, two types of stimuli were used: a version with painted linear perspective cues and a version with blank (unpainted) surfaces. To examine the role of convexity, two locations were used for the fixation mark: either in a locally convex or a locally concave part of each stimulus (painted and unpainted versions). Results indicated that the reverse-perspective illusion was stronger when the stimulus contained strong perspective cues and when observers fixated a locally concave region within the scene.

Keywords: Three-dimensional shape; convexity bias; fixation location; linear perspective; reverse perspective; visual context.