Badcock D R, Wong T L
Department of Psychology, University of Melbourne, Parkville, Victoria, Australia.
Nature. 1990 Feb 8;343(6258):554-5. doi: 10.1038/343554a0.
Human eyes are in constant and rapid motion even when observers try to maintain steady fixation. Also, the visual system has a sluggish temporal response. In combination, these two factors would be expected to blur stimuli and reduce spatial sensitivity. But observers are able to detect a difference in separation of a few seconds of arc between two closely spaced parallel lines. Here we report that even very large amounts of positional jitter of the line pair has minimal impact on this ability. This result is in marked contrast to the deterioration observed when targets are swept linearly across the retina, but is consistent with a system that must ignore oculomotor jitter. To explain these results will require a re-evaluation of current models of position coding in human vision.
即使观察者试图保持稳定注视，人眼仍处于持续且快速的运动中。此外，视觉系统的时间响应较为迟缓。综合这两个因素，预计会使刺激模糊并降低空间敏感度。但观察者能够检测出两条间距很近的平行线之间几秒弧度的间距差异。在此我们报告，即使线对存在非常大量的位置抖动，对这种能力的影响也微乎其微。这一结果与当目标在视网膜上线性扫过时观察到的退化形成显著对比，但与一个必须忽略眼动抖动的系统相一致。要解释这些结果，需要重新评估当前人类视觉中位置编码的模型。
