3D spatial attention effects are independent of projected 2D size and location for older and younger observers
56.306, Tuesday, May 14, 2:45 - 6:45 pm, Royal Ballroom 6-8
Russell Pierce1, G. John Andersen1; 1Psychology, College of Humanities, Arts, and Social Sciences, University of California, Riverside
The majority of experiments on visual spatial attention have been conducted using stimuli positioned and extended in height and width (e.g., B. A. Eriksen & Eriksen, 1974; Posner, Snyder, & Davidson, 1980). However, several experiments have demonstrated that spatial attention varies as a function of depth for both younger and older observers (e.g. Andersen, 1990; Theeuwes, Atchley, & Kramer, 1998). In a recent experiment, we found that the shape of visual spatial attention in the horizontal and depth dimensions was different for older and younger observers (Pierce, Bian, & Andersen, VSS 2011). However, in that experiment the effect of two-dimensional (2D) projected size and position was not experimentally controlled. If spatial attention is 3D, then there should be an effect of target distance when 2D projected size and position are constant. The primary purpose of the current work was to assess this hypothesis. In the current experiment, observers detected a light-change target in an array of lights over a simulated roadway while they performed a car following task. We manipulated the size and position of light-change targets at different depths to hold the projected size and position of targets constant between blocks. Although projected size and position were identical in this experiment, we observed statistically significant differences in RT between targets at a simulated distance further from the observer (younger observers M = 718ms, SD = 246ms; older observers M = 894ms, SD = 287ms) and targets at a simulated distance closer to the observer (younger observers M = 570ms, SD = 137ms; older observers M = 712ms, SD = 190ms), F(1, 46) = 72.09, p <.001. These results demonstrate that 3D attention effects are not dependent on projected size or position, and that the mechanism of 3D attention is present in younger and older observers.