Institute for Frontier Areas of Psychology and Mental Health, Freiburg, Germany.
Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, University of Freiburg, Freiburg, Germany.
PLoS One. 2018 Sep 26;13(9):e0202398. doi: 10.1371/journal.pone.0202398. eCollection 2018.
The present study utilizes perceptual hysteresis effects to compare the ambiguity of Mona Lisa's emotional face expression (high-level ambiguity) and of geometric cube stimuli (low-level ambiguity).
In two experiments we presented series of nine Mona Lisa variants and nine cube variants. Stimulus ambiguity was manipulated by changing Mona Lisa's mouth curvature (Exp. 1) and the cubes' back-layer luminance (Exp. 2). Each experiment consisted of three conditions, two with opposite stimulus presentation sequences with increasing and decreasing degrees of ambiguity, respectively, and a third condition with a random presentation sequence. Participants indicated happy or sad face percepts (Exp. 1) and alternative 3D cube percepts (Exp. 2) by key presses. We studied the influences of a priori perceptual biases (long-term memory) and presentation order (short-term memory) on perception.
Perception followed sigmoidal functions of the stimulus ambiguity morphing parameters. The morphing parameter for the functions' inflection points depended strongly on stimulus presentation order with similar effect sizes but different signs for the two stimulus types (positive hysteresis / priming for the cubes; negative hysteresis / adaptation for Mona Lisa). In the random conditions, the inflection points were located in the middle between those from the two directional conditions for the Mona Lisa stimuli. For the cube stimuli, they were superimposed on one sigmoidal function for the ordered condition.
The hysteresis effects reflect the influence of short-term memory during the perceptual disambiguation of ambiguous sensory information. The effects for the two stimulus types are of similar size, explaining up to 34% of the perceptual variance introduced by the paradigm. We explain the qualitative difference between positive and negative hysteresis with adaptation for Mona Lisa and with priming for the cubes. In addition, the hysteresis paradigm allows a quantitative determination of the impact of adaptation and priming during the resolution of perceptual ambiguities. The asymmetric shifts of inflection points in the case of the cube stimuli is likely due to an a priori perceptual bias, reflecting an influence of long-term memory. Whether corresponding influences also exist for the Mona Lisa variants is so far unclear.
本研究利用感知滞后效应比较蒙娜丽莎情感面部表情（高级别模糊）和几何立方体刺激（低级别模糊）的模糊性。
在两项实验中，我们呈现了九张蒙娜丽莎变体和九张立方体变体的系列。通过改变蒙娜丽莎的嘴形曲率（实验 1）和立方体的背面亮度（实验 2）来操纵刺激的模糊性。每个实验都有三个条件，两个条件的刺激呈现序列分别具有增加和减少的模糊度，第三个条件是随机呈现序列。参与者通过按键指示蒙娜丽莎的快乐或悲伤面部知觉（实验 1）和替代的 3D 立方体知觉（实验 2）。我们研究了先验感知偏差（长期记忆）和呈现顺序（短期记忆）对感知的影响。
感知遵循刺激模糊度变形参数的 S 形函数。函数拐点的变形参数强烈依赖于刺激呈现顺序，对于两种刺激类型，其效应大小相似，但符号不同（立方体为正滞后/启动；蒙娜丽莎为负滞后/适应）。在随机条件下，拐点位于蒙娜丽莎刺激的两个定向条件之间的中间位置。对于立方体刺激，它们叠加在有序条件下的一个 S 形函数上。
滞后效应反映了在感知模糊感测信息的去模糊过程中短期记忆的影响。两种刺激类型的滞后效应大小相似，解释了该范式引入的感知方差的 34%。我们用蒙娜丽莎的适应和立方体的启动来解释正滞后和负滞后的定性差异。此外，滞后效应范式允许定量确定在感知模糊性的解决过程中适应和启动的影响。在立方体刺激的情况下，拐点的不对称偏移可能是由于先验感知偏差，反映了长期记忆的影响。对于蒙娜丽莎变体是否存在类似的影响，目前尚不清楚。
