Abstract
When examining motion in depth and the attentional system, previous studies have reported conflicting results, with some finding attentional prioritization for only approaching motion (Franconeri & Simons, 2003), and others reporting capture for both approaching and receding motion in depth (Skarratt, Cole, & Gellatly, 2009). This discrepancy could be due to at least two factors: 1) differences in the way in which motion in depth was simulated, or 2) a confound between motion in depth and the initial unique depth of the moving object relative to the other distractors. We addressed these factors in two experiments. We used a search paradigm comparing the response time to find a target when it did or did not spatially coincide with the endpoint of an object’s approaching or receding motion. In Experiment 1 we simulated motion in depth using size scaling, binocular disparity, or a combination of the two. The pattern of response times varied with the method used, indicating that the method used to simulate motion in depth is an important factor for this effect. Experiment 2 controlled for the initial depth of the moving target by comparing a condition with the depth singleton removed by spreading items over two depth planes, to a condition with a single depth plane and a depth singleton. We observed shallower search slopes for targets coinciding with an approaching item than a static item in both conditions, as well as speeded response times to approaching motion compared to receding or static targets. Slopes for receding motion were shallower than for static targets only when the moving stimulus constituted a depth singleton. We conclude that low level visual processing of approaching motion is more efficient than for receding motion, and this rapid low level visual processing can increase the salience of approaching motion.
Meeting abstract presented at VSS 2012