Naber Marnix, Hilger Maximilian, Einhäuser Wolfgang
Department of Neurophysics, Philipps University Marburg, Germany.
J Vis. 2012 Jan 26;12(1):25. doi: 10.1167/12.1.25.
Humans process natural scenes rapidly and accurately. Low-level image features and emotional valence affect such processing but have mostly been studied in isolation. At which processing stage these factors operate and how they interact has remained largely unaddressed. Here, we briefly presented natural images and asked observers to report the presence or absence of an animal (detection), species of the detected animal (identification), and their confidence. In a second experiment, the same observers rated images with respect to their emotional affect and estimated their anxiety when imagining a real-life encounter with the depicted animal. We found that detection and identification improved with increasing image luminance, background contrast, animal saturation, and luminance plus color contrast between target and background. Surprisingly, animals associated with lower anxiety were detected faster and identified with higher confidence, and emotional affect was a better predictor of performance than anxiety. Pupil size correlated with detection, identification, and emotional valence judgments at different time points after image presentation. Remarkably, images of threatening animals induced smaller pupil sizes, and observers with higher mean anxiety ratings had smaller pupils on average. In sum, rapid visual processing depends on contrasts between target and background features rather than overall visual context, is negatively affected by anxiety, and finds its processing stages differentially reflected in the pupillary response.
人类能够快速且准确地处理自然场景。低层次图像特征和情感效价会影响这种处理过程，但大多是单独进行研究的。这些因素在哪个处理阶段起作用以及它们如何相互作用，在很大程度上仍未得到解决。在这里，我们简要展示自然图像，并要求观察者报告是否存在动物（检测）、所检测到动物的种类（识别）以及他们的信心。在第二个实验中，相同的观察者对图像的情感影响进行评分，并估计当想象与所描绘动物在现实生活中相遇时他们的焦虑程度。我们发现，随着图像亮度、背景对比度、动物饱和度以及目标与背景之间的亮度加颜色对比度的增加，检测和识别能力得到提高。令人惊讶的是，与较低焦虑相关的动物被更快地检测到且识别的信心更高，并且情感影响比焦虑更能预测表现。瞳孔大小在图像呈现后的不同时间点与检测、识别和情感效价判断相关。值得注意的是，具有威胁性动物的图像会导致瞳孔尺寸变小，并且平均焦虑评分较高的观察者平均瞳孔较小。总之，快速视觉处理取决于目标与背景特征之间的对比度而非整体视觉背景，受到焦虑的负面影响，并且其处理阶段在瞳孔反应中得到不同程度的反映。
