An Analysis of Orientation Bias: A Comparison Between Visual and Pictorial Space in Virtual Reality

Abstract

If participants are asked to orient a face half way between frontal view and profile view, they typically choose an angle somewhere between 30 and 40 degrees. In this study, we demonstrate this phenomenon called orientation bias, and we test the hypothesis that it is directly related to presenting the face in the pictorial space of the flat screen rather than in the egocentric visual space of the observer.Participants were required to use a keyboard to rotate a 3D rendering of a human head to orient it at 45 degrees, that is, half way between frontal and profile view. Employing a repeated-measures design, participants completed two blocks in counterbalanced order. Both viewing conditions were implemented in virtual reality. In the first, participants saw a columnar pedestal with a head mounted on top of it in the visual space before them. In the second block, the very same scene was recorded with a fixed camera and projected on a virtual computer screen.The results indicated that the mean angle estimations in visual space (M = 43.01, SD = 5.96) and pictorial space (M = 37.40, SD = 6.99) differed significantly, t(15) = 5.13, p < .001.These differences could be a result of depth compression, which has been previously described in the context of distance perception. Given that interpretation, our results imply that depth compression might be a result of the flatness of the picture plane which is perceived in a “twofold” way alongside the depicted contents of the image.