van Assen Jan Jaap R, Fleming Roland W
Department of Psychology, Justus-Liebig-University Giessen, Giessen,
J Vis. 2016 Dec 1;16(15):12. doi: 10.1167/16.15.12.
In everyday life we encounter a wide range of liquids (e.g., water, custard, toothpaste) with distinctive optical appearances and viscosities. Optical properties (e.g., color, translucency) are physically independent of viscosity, but, based on experience with real liquids, we may associate specific appearances (e.g., water, caramel) with certain viscosities. Conversely, the visual system may discount optical properties, enabling "viscosity constancy" based primarily on the liquid's shape and motion. We investigated whether optical characteristics affect the perception of viscosity and other properties of liquids. We simulated pouring liquids with viscosities ranging from water to molten glass and rendered them with nine different optical characteristics. In Experiment 1, observers (a) adjusted a match stimulus until it had the same perceived viscosity as a test stimulus with different optical properties, and (b) rated six physical properties of the test stimuli (runniness, shininess, sliminess, stickiness, warmth, wetness). We tested moving and static stimuli. In Experiment 2, observers had to associate names with every liquid in the stimulus set. We find that observers' viscosity matches correlated strongly with the true viscosities and that optical properties had almost no effect. However, some ratings of liquid properties did show substantial interactions between viscosity and optical properties. Observers associate liquid names primarily with optical cues, although some materials are associated with a specific viscosity or combination of viscosity and optics. These results suggest viscosity is inferred primarily from shape and motion cues but that optical characteristics influence recognition of specific liquids and inference of other physical properties.
在日常生活中，我们会遇到各种各样具有独特光学外观和粘度的液体（例如水、蛋奶糊、牙膏）。光学特性（例如颜色、半透明性）在物理上与粘度无关，但是，基于对实际液体的经验，我们可能会将特定的外观（例如水、焦糖）与某些粘度联系起来。相反，视觉系统可能会忽略光学特性，从而主要基于液体的形状和运动实现“粘度恒常性”。我们研究了光学特性是否会影响对液体粘度和其他特性的感知。我们模拟了从水到熔融玻璃等不同粘度液体的倾倒过程，并赋予它们九种不同的光学特性。在实验1中，观察者（a）调整一个匹配刺激，直到它与具有不同光学特性的测试刺激具有相同的感知粘度，并且（b）对测试刺激的六种物理特性（流动性、光泽度、滑腻感、粘性、温热感、湿润感）进行评分。我们测试了动态和静态刺激。在实验2中，观察者必须为刺激集中的每种液体命名。我们发现观察者的粘度匹配与真实粘度密切相关，而光学特性几乎没有影响。然而，一些液体特性的评分确实显示出粘度和光学特性之间存在显著的相互作用。观察者主要根据光学线索为液体命名，尽管有些材料与特定的粘度或粘度与光学特性的组合相关联。这些结果表明，粘度主要是从形状和运动线索推断出来的，但光学特性会影响对特定液体的识别以及对其他物理特性的推断。
