Abstract
Previously, we demonstrated that there is an interaction between object surface material and perception of angular velocity (Kucukoglu, Maloney, 2013): specular objects were judged to be moving faster than matte (Lambertian) objects matched in rotational velocity. This year we considered three classes of objects: specular, matte, and matte with albedo surface texture. The stimuli were irregular, blob-like shapes rendered with specular, matte or textured materials. Their angular velocity ranged between 6°/sec to 84°/sec. We had three conditions: (1) textured vs. specular, (2) specular vs. matte and (3) textured vs. matte. In all of these conditions, on a given trial subjects saw a pair of rotating objects – e.g. one specular, one textured – presented one after the other. The task was to pick the faster rotating object in the pair. We used a staircase paradigm to adjust the angular velocity of the objects to the point of subjective equal angular velocity.Three out of four subjects in condition 1 show a significant bias in perceiving textured objects to be faster than the specular objects. Condition two is a repetition of our previous task but this time with slower angular velocities. Two out of four subjects in condition 2 show a bias towards perceiving specular objects to be faster than matte objects. If textured is perceived to be faster than specular (A>B) and specular is faster than matte (B>C) we would expect to find a bias towards perceiving textured to be faster than matte (A>C). However, we do not find any significant bias between textured and matte objects (we do not reject A=C for any subject). We present a cue integration model of estimation of angular velocity proposing that dynamic reweighting of different cues to angular velocity accounts for the observed intransitivity.
Meeting abstract presented at VSS 2014