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J Vis. 2020 Apr 9;20(4):15. doi: 10.1167/jov.20.4.15.
Fixation durations provide insights into processing demands. We investigated factors controlling fixation durations during scene viewing in two experiments. In Experiment 1, we tested the degree to which fixation durations adapt to global scene processing difficulty by manipulating the contrast (from original contrast to isoluminant) and saturation (original vs. grayscale) of the entire scene. We observed longer fixation durations for lower levels of contrast, and longer fixation durations for grayscale than for color scenes. Thus fixation durations were globally slowed as visual information became more and more degraded, making scene processing increasingly more difficult. In Experiment 2, we investigated two possible sources for this slow-down. We used "checkerboard" stimuli in which unmodified patches alternated with patches from which luminance information had been removed (isoluminant patches). Fixation durations showed an inverted immediacy effect (longer, rather than shorter, fixation durations on unmodified patches) along with a parafoveal-on-foveal effect (shorter fixation durations, when an unmodified patch was fixated next). This effect was stronger when the currently fixated patch was isoluminant as opposed to unmodified. Our results suggest that peripheral scene information substantially affects fixation durations and are consistent with the notion of competition among the current and potential future fixation locations.
注视持续时间提供了对处理需求的深入了解。我们在两个实验中研究了控制场景观看过程中注视持续时间的因素。在实验 1 中，我们通过操纵整个场景的对比度（从原始对比度到等明度）和饱和度（原始与灰度）来测试注视持续时间适应全局场景处理难度的程度。我们观察到，对比度越低，注视持续时间越长，灰度场景比彩色场景的注视持续时间更长。因此，随着视觉信息的退化越来越严重，场景处理变得越来越困难，注视持续时间也会全局变慢。在实验 2 中，我们研究了这种减速的两个可能来源。我们使用了“棋盘”刺激，其中未修改的补丁与亮度信息已被移除的补丁（等明度补丁）交替出现。注视持续时间显示出颠倒的即时效应（未修改的补丁上的注视持续时间更长，而不是更短），以及旁中心注视到中央注视的效应（当注视下一个未修改的补丁时，注视持续时间更短）。当当前注视的补丁是等明度而不是未修改时，这种效应更强。我们的结果表明，周边场景信息会极大地影响注视持续时间，这与当前和潜在未来注视位置之间的竞争概念是一致的。
