Abstract
Prior research (e.g., Andersen & Atchley, 1995; Norman, Dawson, & Butler, 2000; Norman, Clayton, Shular, & Thompson, 2004; Norman, Bartholomew, & Burton, 2008) has examined the detectability and discriminability of curved 3-D surfaces defined by optical motion. These studies have demonstrated that the performance of older adults (60 to 85 years of age) is frequently worse than that exhibited by younger adults (20 to 30 years of age). Nothing is presently known, however, about the perceptual capabilities of middle-aged adults. One goal of the present study was to study the decline in the ability to perceive 3-D shape from motion in more detail. For example, does the ability to perceive 3-D shape from motion decline continuously throughout the lifespan, or does it remain high throughout middle adulthood and only deteriorate at later ages? In the current study, 30 adults (ages ranged from 19 to 84 years) discriminated between three smoothly curved surfaces. The surfaces all had sinusoidal depth modulations, where the resulting peaks and troughs formed concentric circles, were radially-oriented, or were arranged like an "egg-crate" (depth = sin(x) * sin(y)). The visibility of the surfaces was degraded to varying degrees by limiting the lifetimes of the surfaces’ constituent points. Psychometric functions relating discrimination accuracy to surface point lifetime (number of successive views in the apparent motion sequence during which individual surface points were presented) were determined for each observer.Hidden formatting deleted. Delete this text! yes"> The point lifetime thresholds (i.e., the point lifetime needed for 66.7 percent discrimination performance) were 4.0 views, 4.9 views, and 9.0 views for younger, middle-aged, and older observers, respectively. Our results reveal that the ability to perceive 3-D shape from motion persists throughout middle adulthood and only begins to decline at later ages (e.g., 65 years of age or older).
Meeting abstract presented at VSS 2012