Abstract
Usually visual spatial attention is measured using two-dimensional (2D) stimuli with the implicit assumption that the scope of 2D spatial attention has a direct relationship to the extent and shape of three-dimensional (3D) spatial attention. However, several experiments have demonstrated that spatial attention varies as a function of distance (e.g. Andersen, 1990; Andersen & Kramer, 1993; Ferlazzo et al., 2008; Maringelli et al., 2001). Similar results have been found for older observers (Atchley & Kramer, 1998). In addition, the efficiency with which 2D spatial attention shifts occur in older adults may be equivalent to younger observers (Folk & Hoyer, 1992). However, the useful field of view (UFOV; Sekuler & Ball, 1986), a measure of 2D spatial attention, provides evidence that the scope of 2D visual attention is reduced in older adults. The current experiment was designed to assess whether 3D spatial attention differs as a function of age and how task difficulty changed the extent of attention. Specifically, we used a driving scenario to examine 3D attention by requiring participants' to detect a light-change target in an array of lights over a simulated roadway while they performed a car following task. We found that reaction time to light-change targets varied as a function of distance and horizontal position in younger adults, but only as a function of distance in older adults. As a result, reaction time for older observers did not vary as a function of horizontal position at the greatest distance examined. These results indicate the shape of spatial attention in the horizontal and depth dimensions is different for older and younger observers.
NIH AG031941 and NIH EY18334.