Aging and the detection of moving objects defined by common fate

Abstract

Grouping by common fate plays an important role in how human observers perceive environmental objects. In this study, the effect of aging upon the ability to utilize common fate was evaluated. Twenty-two younger and older adults (mean ages were 23.4 and 74.7 years, respectively) participated in two experiments. On any given trial, the participants sequentially viewed two apparent motion sequences and were required to indicate which temporal interval contained a coherently moving dotted line embedded in noisy random background motion. In Experiment 1, the number of dots defining the target was varied, while in Experiment 2, the target interpoint spacing was varied. The younger adults outperformed the older adults by 19.4 percent in Experiment 1 and 50.5 percent in Experiment 2. The older and younger adults were similarly affected by variations in the number of target dots and the target interpoint spacing. The individual older participants’ object detection accuracies were highly correlated with their individual chronological ages, such that the performance of the younger old participants was much higher than that exhibited by the older old. Increases in age systematically affect the ability of older adults to detect and visually perceive objects defined by common fate.

Aging and temporal integration in the visual perception of object shape

“…It is important to remember, however, that substantial age-related deficits frequently occur for tasks involving the judgment of either the speed or direction of motion 11 – 19 . Furthermore, aging apparently results in a reduction in inhibition within motion-sensitive cortical brain areas 45 , 46 ; this reduced inhibition produces deficits in such fundamental and important visual abilities as figure-ground segregation 46 , 47 . In their 2008 article, Billino et al 17 conclude by saying (p. 1260) “our findings support the hypothesis that perceptual capabilities are not equally prone to age-related deterioration”.…”