Ball K, Sekuler R
J Gerontol. 1986 Mar;41(2):176-82. doi: 10.1093/geronj/41.2.176.
Younger observers (M = 21 years) proved to be better than older observers (M = 68 years) at discriminating one direction of motion from another, highly similar one. Several days' practice steadily improved performance for both groups equally. Improvement was well restricted to the direction with which that observer practiced, and the full gains were retained for at least 1 month. Control measurements with various degrees of optical blur demonstrate that direction discrimination does not require a well-focussed retinal image. This rules out optical factors as the potential cause of the prepractice differences between groups.
事实证明，较年轻的观察者（平均年龄21岁）在区分一个运动方向与另一个高度相似的运动方向方面，比年长的观察者（平均年龄68岁）表现更好。几天的练习使两组的表现都同样稳步提高。这种提高很好地局限于观察者练习的方向，并且全部的进步至少保持了1个月。用各种不同程度的光学模糊进行的对照测量表明，方向辨别并不需要清晰聚焦的视网膜图像。这排除了光学因素作为两组练习前差异的潜在原因。
