Viviani P, Swensson R G
J Exp Psychol Hum Percept Perform. 1982 Feb;8(1):113-26. doi: 10.1037//0096-1523.8.1.113.
Two experiments required subjects to identify a peripheral target embedded among nontarget stimuli and fixate it as quickly as possible with a single saccadic eye movement. Experiment 1 varied both the target distance and its angular position between trials; the mean oculomotor latency, the proportion of erroneous movements, and the proportion of (correct) movements followed by a corrective saccade all increased as a function of target distance. Experiment 2 held target distance constant (12.7 degrees) and used verbal instructions to manipulate the speed and accuracy of the subject's oculomotor performance between conditions. The speed/accuracy trade-off was similar for all subjects. The reduced uncertainty about target distance in Experiment 2 made each subject's oculomotor performance more efficient. Error trials not only included apparent perceptual errors (initial movements to nontarget stimuli) but also motor errors - that is, instances when the initial erroneous movement was followed, with an extremely short latency, by a large saccade to the target. The characteristics of these motor errors suggest that the saccade is not planned in terms of its amplitude and direction in retinal coordinates.
两项实验要求受试者识别嵌入非目标刺激中的周边目标，并通过一次眼跳运动尽快注视该目标。实验1在各试验中改变目标距离及其角位置；平均眼动潜伏期、错误运动比例以及随后伴有纠正性眼跳的（正确）运动比例均随目标距离的增加而增加。实验2将目标距离保持恒定（12.7度），并使用言语指令在不同条件下操纵受试者眼动表现的速度和准确性。所有受试者的速度/准确性权衡情况相似。实验2中目标距离的不确定性降低，使每个受试者的眼动表现更高效。错误试验不仅包括明显的感知错误（最初向非目标刺激的运动），还包括运动错误——也就是说，最初的错误运动之后紧接着极短潜伏期的、朝向目标的大幅度眼跳的情况。这些运动错误的特征表明，眼跳并非根据其在视网膜坐标中的幅度和方向来规划。
