Abteilung Allgemeine Psychologie, Justus Liebig University Giessen, 35394 Giessen, Germany.
Department of Psychology, Philipps University of Marburg, 35032 Marburg, Germany.
Proc Natl Acad Sci U S A. 2018 Feb 27;115(9):2240-2245. doi: 10.1073/pnas.1704799115. Epub 2018 Feb 13.
Due to the foveal organization of our visual system we have to constantly move our eyes to gain precise information about our environment. Doing so massively alters the retinal input. This is problematic for the perception of moving objects, because physical motion and retinal motion become decoupled and the brain has to discount the eye movements to recover the speed of moving objects. Two different types of eye movements, pursuit and saccades, are combined for tracking. We investigated how the way we track moving targets can affect the perceived target speed. We found that the execution of corrective saccades during pursuit initiation modifies how fast the target is perceived compared with pure pursuit. When participants executed a forward (catch-up) saccade they perceived the target to be moving faster. When they executed a backward saccade they perceived the target to be moving more slowly. Variations in pursuit velocity without corrective saccades did not affect perceptual judgments. We present a model for these effects, assuming that the eye velocity signal for small corrective saccades gets integrated with the retinal velocity signal during pursuit. In our model, the execution of corrective saccades modulates the integration of these two signals by giving less weight to the retinal information around the time of corrective saccades.
由于我们视觉系统的中央凹组织，我们必须不断移动眼睛以获取有关环境的精确信息。这样做会极大地改变视网膜输入。这对于移动物体的感知来说是个问题，因为物理运动和视网膜运动变得分离，大脑必须扣除眼球运动以恢复移动物体的速度。两种不同类型的眼球运动，追踪和扫视，被结合起来用于跟踪。我们研究了跟踪移动目标的方式如何影响感知到的目标速度。我们发现，在进行追踪启动时执行校正性扫视会改变与纯追踪相比目标被感知的速度。当参与者执行向前（追上）扫视时，他们感知到目标移动得更快。当他们执行向后扫视时，他们感知到目标移动得更慢。没有校正性扫视的追踪速度变化不会影响感知判断。我们提出了一个模型来解释这些效应，假设小校正性扫视的眼动速度信号在追踪过程中与视网膜速度信号进行整合。在我们的模型中，执行校正性扫视会通过在校正性扫视前后减少对视网膜信息的权重来调节这两个信号的整合。
