Stimulus persistence and age

Stimulus persistence theory states that the effects of stimulation are longer lasting in the nervous system of the old person than the younger one. This concept and its relation to perceptual functioning and age was examined via two perceptual aftereffect tasks, the Spiral and the Waterfall. Twenty-four elderly adults (mean age = 65.5) and twenty-four young adults (mean age = 24.8) were each exposed to both stimulus displays, at four exposure durations: 45, 60, 90, and 120 seconds. Following the offset of each display, the duration of any apparent motion aftereffect was recorded. Although on the basis of stimulus persistence theory it was expected that the elderly would exhibit longer mean aftereffects than the young, no support for this hypothesis was noted. Possible explanations of these results and their relation to previous findings, in terms of fatigue effects and sample characteristics, are discussed.