Faculty of Art and Design, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8574, Japan.
BMC Psychol. 2022 Dec 6;10(1):291. doi: 10.1186/s40359-022-01006-0.
Studies have shown that viewing a cluster of dots evokes feelings of discomfort in viewers and that the discomfort becomes especially strong when the dots are placed on background images of human skin. This phenomenon has been explained by the physical properties and spatial and semantic relationships between the dots and the background. However, it was not known whether the perceived, as well as the physical, spatial relationships contributes to the generation of discomfort.
We evoked illusory depth perception between black dots and the background face by drawing shadow-like gray dots around the black dots, while keeping the same black dots at the same positions, and examined whether illusory depth perception could increase or decrease discomfort. In each trial, participants viewed one of the following types of facial images: (a) face-only (face without dots), (b) a cluster of black dots on the face, (c) a cluster of gray dots on the face, and (d) a cluster of black dots and shadow-like gray dots on the face. After seeing each picture, they evaluated how much discomfort they felt from viewing the picture using a Likert scale and reported whether they perceived depth between the dots and the face.
Participants felt discomfort toward all three types of faces with dots, that is, faces with black dots, gray dots, and both. However, interestingly, participants felt less discomfort when both black and gray dots were presented on the face than when only black dots were presented. The participants perceived depth between the black dots and the face in 85% of the trials with black dots and shadow-like gray dots, and there was a significant correlation between discomfort and frequency of depth perception. However, in the trials with black dots only and gray dots only, they perceived depth in only 18% and 27% of the trials, respectively, and the correlations between the frequencies of depth perception and discomfort were not significant.
Our results suggest that the perceived spatial relationship, such as attached vs. separate, as well as the physical spatial relationship, contribute to the generation of discomfort.
研究表明，观看一群点会引起观看者的不适，而当这些点放置在人类皮肤的背景图像上时，不适会变得特别强烈。这种现象可以用点与背景之间的物理性质和空间及语义关系来解释。然而，人们不知道感知到的以及物理上的空间关系是否有助于产生不适。
我们通过在黑点周围绘制类似阴影的灰色点来在黑点和背景面部之间产生错觉深度感知，同时保持相同的黑点处于相同位置，并检查错觉深度感知是否可以增加或减少不适。在每个试验中，参与者观看以下类型的面部图像之一：（a）仅面部（无点的面部），（b）面部上的一群黑色点，（c）面部上的一群灰色点，和（d）面部上的一群黑色点和类似阴影的灰色点。在看到每张图片后，他们使用李克特量表评估观看图片时的不适程度，并报告他们是否感知到点与面部之间的深度。
参与者对所有三种带有点的面部类型都感到不适，即带有黑色点、灰色点和两者的面部。然而，有趣的是，当黑色和灰色点都出现在面部上时，参与者感到的不适程度比只有黑色点时要小。参与者在 85%的带有黑色点和类似阴影的灰色点的试验中感知到了点与面部之间的深度，不适感与深度感知频率之间存在显著相关性。然而，在只有黑色点和只有灰色点的试验中，他们分别只有 18%和 27%的试验中感知到了深度，深度感知频率与不适感之间的相关性不显著。
我们的结果表明，感知到的空间关系，例如附着的与分离的，以及物理空间关系，有助于产生不适。
