Norman J Farley, Burton Cory L, Best Leah A
Department of Psychology, Western Kentucky University, Bowling Green, KY 42101-1030, United States.
Vision Res. 2010 Jan;50(1):65-71. doi: 10.1016/j.visres.2009.10.009.
Two experiments investigated modulatory effects of a surround upon the perceived speed of a moving central region. Both the surround's depth and velocity (relative to the center) were manipulated. The abilities of younger observers (mean age was 23.1 years) were evaluated in Experiment 1, while Experiment 2 was devoted to older participants (mean age was 71.3 years). The results of Experiment 1 revealed that changes in the perceived depth of a surround (in this case caused by changes in binocular disparity) significantly influence the perceived speed of a central target. In particular, the center's motion was perceived as fastest when the surround possessed uncrossed binocular disparity relative to the central target. This effect, that targets that are closer than their background are perceived to be faster, only occurred when the center and surround moved in the same directions (and did not occur when center and surround moved in opposite directions). The results of Experiment 2 showed that the perceived speeds of older adults are different: older observers generally perceive nearer targets as faster both when center and surround move in the same direction and when they move in opposite directions. In addition, the older observers' judgments of speed were less precise. These age-related changes in the perception of speed are broadly consistent with the results of recent neurophysiological investigations that find age-related changes in the functionality of cortical area MT.
两项实验研究了周围环境对移动的中央区域视速度的调节作用。实验中同时操控了周围环境的深度和速度（相对于中央区域）。实验1评估了年轻观察者（平均年龄23.1岁）的能力，而实验2则聚焦于年长参与者（平均年龄71.3岁）。实验1的结果显示，周围环境感知深度的变化（在本实验中由双眼视差的变化引起）会显著影响中央目标的视速度。具体而言，当周围环境相对于中央目标具有非交叉双眼视差时，中央区域的运动被感知为最快。这种比背景更近的目标被感知为更快的效应，仅在中央区域和周围环境同向移动时出现（当中央区域和周围环境反向移动时不出现）。实验2的结果表明，年长者的视速度有所不同：年长观察者通常在中央区域和周围环境同向移动以及反向移动时，都会将更近的目标感知为更快。此外，年长观察者的速度判断准确性较低。这些与年龄相关的速度感知变化与近期神经生理学研究结果大致相符，该研究发现与年龄相关的MT皮质区域功能变化。
