Department of Psychology, University of Toronto, Ontario, Canada.
Psychol Sci. 2013 Jun;24(6):957-65. doi: 10.1177/0956797612464500. Epub 2013 Apr 25.
Facial expressions may have originated from a primitive sensory regulatory function that was then co-opted and further shaped for the purposes of social utility. In the research reported here, we tested such a hypothesis by investigating the functional origins of fear expressions for both the expresser and the observer. We first found that fear-based eye widening enhanced target discrimination in the available visual periphery of the expresser by 9.4%. We then found that fear-based eye widening enhanced observers' discrimination of expressers' gaze direction and facilitated observers' responses when locating eccentric targets. We present evidence that this benefit was driven by neither the perceived emotion nor attention but, rather, by an enhanced physical signal originating from greater exposure of the iris and sclera. These results highlight the coevolution of sensory and social regulatory functions of emotional expressions by showing that eye widening serves to enhance processing of important environmental events in the visual fields of both expresser and observer.
面部表情可能起源于一种原始的感觉调节功能，后来被借用并进一步塑造，以达到社会效用的目的。在本研究中，我们通过研究表达者和观察者的恐惧表情的功能起源来验证这一假设。我们首先发现，基于恐惧的眼睛睁大增强了表达者在可用视觉外围的目标识别，提高了 9.4%。然后我们发现，基于恐惧的眼睛睁大增强了观察者对表达者注视方向的辨别能力，并有助于观察者在定位偏心目标时的反应。我们提出的证据表明，这种好处既不是由感知到的情绪引起的，也不是由注意力引起的，而是由虹膜和巩膜更大暴露引起的增强的物理信号引起的。这些结果通过表明眼睛睁大有助于增强表达者和观察者的视觉场中重要环境事件的处理，突出了情感表达的感觉和社会调节功能的共同进化。
