Chemnitz University of Technology, Institute of Physics, Physics of Cognition Group, Germany; Chemnitz University of Technology, Institute of Physics, Cognitive Systems Lab, Germany.
Chemnitz University of Technology, Institute of Physics, Physics of Cognition Group, Germany; Chemnitz University of Technology, Institute of Physics, Cognitive Systems Lab, Germany.
Vision Res. 2021 May;182:69-88. doi: 10.1016/j.visres.2020.12.006. Epub 2021 Feb 17.
In multistability, perceptual interpretations ("percepts") of ambiguous stimuli alternate over time. There is considerable debate as to whether similar regularities govern the first percept after stimulus onset and percepts during prolonged presentation. We address this question in a visual pattern-component rivalry paradigm by presenting two overlaid drifting gratings, which participants perceived as individual gratings passing in front of each other ("segregated") or as a plaid ("integrated"). We varied the enclosed angle ("opening angle") between the gratings (experiments 1 and 2) and stimulus orientation (experiment 2). The relative number of integrated percepts increased monotonically with opening angle. The point of equality, where half of the percepts were integrated, was at a smaller opening angle at onset than during prolonged viewing. The functional dependence of the relative number of integrated percepts on opening angle showed a steeper curve at onset than during prolonged viewing. Dominance durations of integrated percepts were longer at onset than during prolonged viewing and increased with opening angle. The general pattern persisted when stimuli were rotated (experiment 2), despite some perceptual preference for cardinal motion directions over oblique directions. Analysis of eye movements, specifically the slow phase of the optokinetic nystagmus (OKN), confirmed the veridicality of participants' reports and provided a temporal characterization of percept formation after stimulus onset. Together, our results show that the first percept after stimulus onset exhibits a different dependence on stimulus parameters than percepts during prolonged viewing. This underlines the distinct role of the first percept in multistability.
在多稳定性中，对模棱两可刺激的感知解释（“感知”）会随时间交替。关于在刺激开始后和长时间呈现期间的第一个感知是否受到类似规则的支配，存在相当大的争议。我们在视觉模式成分竞争范式中解决了这个问题，该范式通过呈现两个重叠的漂移光栅来实现，参与者将其感知为单个光栅相互交叉而过（“分离”）或作为格子（“整合”）。我们改变了光栅之间的封闭角（“开口角”）（实验 1 和 2）和刺激方向（实验 2）。与开口角成正比的整合感知的相对数量呈单调增加。在开始时，一半的感知是整合的，此时的开口角比长时间观看时的开口角小。整合感知的相对数量与开口角的函数依赖性在开始时比长时间观看时呈现出更陡峭的曲线。整合感知的主导持续时间在开始时比长时间观看时更长，并随开口角增加而增加。当刺激旋转时（实验 2），尽管存在对垂直运动方向的感知偏好，但总体模式仍然存在。对眼球运动的分析，特别是视动性眼球震颤（OKN）的慢相，证实了参与者报告的真实性，并提供了刺激开始后感知形成的时间特征。总的来说，我们的结果表明，在刺激开始后的第一个感知与长时间观看期间的感知对刺激参数的依赖性不同。这强调了第一个感知在多稳定性中独特的作用。
