Tonelli Alessia, Cuturi Luigi F, Gori Monica
Unit for Visually Impaired People, Science and Technology for Children and Adults, Istituto Italiano di Tecnologia, Genoa, Italy.
Robotics, Brain and Cognitive Sciences Department, Istituto Italiano di Tecnologia, Genoa, Italy.
Front Neurosci. 2017 Oct 24;11:594. doi: 10.3389/fnins.2017.00594. eCollection 2017.
Size perception can be influenced by several visual cues, such as spatial (e.g., depth or vergence) and temporal contextual cues (e.g., adaptation to steady visual stimulation). Nevertheless, perception is generally multisensory and other sensory modalities, such as auditory, can contribute to the functional estimation of the size of objects. In this study, we investigate whether auditory stimuli at different sound pitches can influence visual size perception after visual adaptation. To this aim, we used an adaptation paradigm (Pooresmaeili et al., 2013) in three experimental conditions: visual-only, visual-sound at 100 Hz and visual-sound at 9,000 Hz. We asked participants to judge the size of a test stimulus in a size discrimination task. First, we obtained a baseline for all conditions. In the visual-sound conditions, the auditory stimulus was concurrent to the test stimulus. Secondly, we repeated the task by presenting an adapter (twice as big as the reference stimulus) before the test stimulus. We replicated the size aftereffect in the visual-only condition: the test stimulus was perceived smaller than its physical size. The new finding is that we found the auditory stimuli have an effect on the perceived size of the test stimulus after visual adaptation: low frequency sound decreased the effect of visual adaptation, making the stimulus perceived bigger compared to the visual-only condition, and contrarily, the high frequency sound had the opposite effect, making the test size perceived even smaller.
大小感知会受到多种视觉线索的影响，比如空间线索（如深度或辐辏）和时间背景线索（如对稳定视觉刺激的适应）。然而，感知通常是多感官的，其他感官模态，如听觉，也会对物体大小的功能估计产生影响。在本研究中，我们探究了在视觉适应后，不同音高的听觉刺激是否会影响视觉大小感知。为此，我们在三种实验条件下采用了一种适应范式（Pooresmaeili等人，2013年）：仅视觉条件、100赫兹的视觉-听觉条件和9000赫兹的视觉-听觉条件。我们要求参与者在大小辨别任务中判断一个测试刺激的大小。首先，我们为所有条件获取了一个基线。在视觉-听觉条件下，听觉刺激与测试刺激同时呈现。其次，我们在呈现测试刺激之前先呈现一个适配器（比参考刺激大两倍），然后重复该任务。我们在仅视觉条件下复制了大小后效：测试刺激被感知为比其实际尺寸小。新的发现是，我们发现在视觉适应后，听觉刺激会对测试刺激的感知大小产生影响：低频声音降低了视觉适应的效果，使得刺激比仅视觉条件下被感知得更大，相反，高频声音则产生相反的效果，使得测试大小被感知得更小。
