Platonov Artem, Goossens Jeroen
Radboud University Medical Centre Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Dept. of Cognitive Neuroscience, section Biophysics, Nijmegen, The Netherlands.
J Vis. 2014 Sep 2;14(11):2. doi: 10.1167/14.11.2.
Binocular rivalry provides a valuable means to study how sensory processing gives rise to subjective experiences because it involves a changing percept without any change in the visual stimulus. An important question, however, is whether visual awareness is necessary for binocular rivalry to emerge. To address this question, we presented conflicting random dot motion stimuli in the two eyes at luminance contrasts around perceptual threshold. We asked subjects to report continuously, via button presses, if they noticed any kind of motion in the display (be it coherent or not) and indicate which direction of motion they thought was dominant at any given instant even if they were unaware of any motion in the display. We biased the competition between the two dichoptic stimuli by changing the motion coherence in one eye while keeping it fixed in the other to test if this induced predictable changes in rivalry dynamics. We also probed the strength of the interocular suppression. Our data show that binocular rivalry continues even if subjects claim complete absence of visual motion awareness. This remarkable dissociation between visually guided behavior and visual awareness resembles the dissociation seen in other phenomena, such as blindsight and visual masking. Fluctuations in awareness that did occur were temporally linked to the dominance switches in a manner that is consistent with adaptation reciprocal-inhibition models of binocular rivalry.
双眼竞争提供了一种宝贵的手段来研究感觉加工如何产生主观体验,因为它涉及到在视觉刺激没有任何变化的情况下感知的变化。然而,一个重要的问题是,视觉意识对于双眼竞争的出现是否必要。为了解决这个问题,我们在接近感知阈值的亮度对比度下,在两只眼睛中呈现相互冲突的随机点运动刺激。我们要求受试者通过按键持续报告他们是否注意到显示屏上有任何类型的运动(无论是否连贯),并指出他们认为在任何给定时刻占主导地位的运动方向,即使他们没有意识到显示屏上有任何运动。我们通过改变一只眼睛中的运动连贯性,同时保持另一只眼睛中的运动连贯性不变,来偏向两种双眼刺激之间的竞争,以测试这是否会引起竞争动态的可预测变化。我们还探究了双眼抑制的强度。我们的数据表明,即使受试者声称完全没有视觉运动意识,双眼竞争仍会继续。这种视觉引导行为与视觉意识之间显著的分离类似于在其他现象中看到的分离,如盲视和视觉掩蔽。确实发生的意识波动在时间上与优势切换相关联,其方式与双眼竞争的适应性相互抑制模型一致。