Department of Psychiatry and Psychotherapy, University Medical Center Freiburg, Freiburg, Germany.
PLoS One. 2012;7(7):e41792. doi: 10.1371/journal.pone.0041792. Epub 2012 Jul 25.
Diagnostic features of emotional expressions are differentially distributed across the face. The current study examined whether these diagnostic features are preferentially attended to even when they are irrelevant for the task at hand or when faces appear at different locations in the visual field. To this aim, fearful, happy and neutral faces were presented to healthy individuals in two experiments while measuring eye movements. In Experiment 1, participants had to accomplish an emotion classification, a gender discrimination or a passive viewing task. To differentiate fast, potentially reflexive, eye movements from a more elaborate scanning of faces, stimuli were either presented for 150 or 2000 ms. In Experiment 2, similar faces were presented at different spatial positions to rule out the possibility that eye movements only reflect a general bias for certain visual field locations. In both experiments, participants fixated the eye region much longer than any other region in the face. Furthermore, the eye region was attended to more pronouncedly when fearful or neutral faces were shown whereas more attention was directed toward the mouth of happy facial expressions. Since these results were similar across the other experimental manipulations, they indicate that diagnostic features of emotional expressions are preferentially processed irrespective of task demands and spatial locations. Saliency analyses revealed that a computational model of bottom-up visual attention could not explain these results. Furthermore, as these gaze preferences were evident very early after stimulus onset and occurred even when saccades did not allow for extracting further information from these stimuli, they may reflect a preattentive mechanism that automatically detects relevant facial features in the visual field and facilitates the orientation of attention towards them. This mechanism might crucially depend on amygdala functioning and it is potentially impaired in a number of clinical conditions such as autism or social anxiety disorders.
情绪表达的诊断特征在面部的分布是不同的。本研究旨在探讨这些诊断特征是否会被优先注意，即使它们与当前任务无关，或者当面部出现在视野的不同位置时。为此，在两项实验中，向健康个体呈现恐惧、快乐和中性面孔，同时测量眼动。在实验 1 中，参与者必须完成情绪分类、性别识别或被动观看任务。为了区分快速、可能是反射性的眼动和更细致的面部扫描，刺激呈现时间分别为 150 或 2000 毫秒。在实验 2 中，呈现相似的面孔在不同的空间位置，以排除眼动仅反映对特定视野位置的一般偏向的可能性。在这两个实验中，参与者注视眼睛区域的时间都比注视面部其他区域的时间长得多。此外，当呈现恐惧或中性面孔时，眼睛区域会被更显著地注视，而当呈现快乐表情时，注意力会更多地集中在嘴巴上。由于这些结果在其他实验操作中相似，它们表明情绪表达的诊断特征被优先处理，而不受任务需求和空间位置的影响。显著性分析表明，基于下传视觉注意的计算模型无法解释这些结果。此外，由于这些注视偏好在刺激出现后非常早期就出现，并且即使眼跳不允许从这些刺激中提取更多信息，它们也可能反映了一种非注意机制，该机制自动检测视野中相关的面部特征，并促进注意力朝向它们的定向。这种机制可能严重依赖于杏仁核的功能，并且在许多临床情况下可能会受到损害，如自闭症或社交焦虑障碍。
