Faces in the wild: A naturalistic study of children’s facial expressions in response to an Internet prank

There is surprisingly little empirical evidence supporting theoretical and anecdotal claims regarding the spontaneous production of prototypic facial expressions used in numerous emotion recognition studies. Proponents of innate prototypic expressions believe that this lack of evidence may be due to ethical restrictions against presenting powerful elicitors in the lab. The current popularity of internet platforms designed for public sharing of videos allows investigators to shed light on this debate by examining naturally-occurring facial expressions outside the laboratory. An Internet prank (“Scary Maze”) has provided a unique opportunity to observe children reacting to a consistent fear- and surprise-inducing stimulus: The unexpected presentation of a “scary face” during an online maze game. The purpose of this study was to examine children’s facial expressions in this naturalistic setting. Emotion ratings of non-facial behaviour (provided by untrained undergraduates) and anatomically-based facial codes were obtained from 60 videos of children (ages 4–7) found on YouTube. Emotion ratings were highest for fear and surprise. Correspondingly, children displayed more facial expressions of fear and surprise than for other emotions (e.g. anger, joy). These findings provide partial support for the ecological validity of fear and surprise expressions. Still prototypic expressions were produced by fewer than half the children.

现有大量情绪识别研究均采用原型面部表情（prototypic facial expressions），但支撑其自发性产生这一理论与传闻主张的实证证据却寥寥无几，这一点出人意料。主张先天原型面部表情存在的研究者认为，此类证据缺失或许源于实验室中呈现强效情绪诱发刺激所面临的伦理限制。当下广受普及的公共视频分享互联网平台，为研究者脱离实验室环境观察自然产生的面部表情、进而阐明这一学术争议提供了契机。一场名为“恐怖迷宫（Scary Maze）”的网络恶作剧，为观察儿童对恒定恐惧与惊讶诱发刺激的反应提供了独特契机——该刺激即在线迷宫游戏中突然出现的“恐怖鬼脸”。本研究旨在探究该自然场景下儿童的面部表情表现。研究人员从YouTube平台抓取了60段4至7岁儿童的视频，从中提取了非面部行为的情绪评分（由未接受训练的本科生提供）以及基于解剖学的面部编码。情绪评分在恐惧与惊讶维度上得分最高。相应地，儿童表现出的恐惧与惊讶类面部表情数量也多于愤怒、喜悦等其他情绪。本研究结果为恐惧与惊讶表情的生态效度提供了部分支撑，但仅有不足半数的儿童产生了原型面部表情。