The Ohio State University, Columbus, OH, United States.
Purdue University, West Lafayette, IN, United States.
Cognition. 2016 May;150:77-84. doi: 10.1016/j.cognition.2016.02.004. Epub 2016 Feb 9.
Facial expressions of emotion are thought to have evolved from the development of facial muscles used in sensory regulation and later adapted to express moral judgment. Negative moral judgment includes the expressions of anger, disgust and contempt. Here, we study the hypothesis that these facial expressions of negative moral judgment have further evolved into a facial expression of negation regularly used as a grammatical marker in human language. Specifically, we show that people from different cultures expressing negation use the same facial muscles as those employed to express negative moral judgment. We then show that this nonverbal signal is used as a co-articulator in speech and that, in American Sign Language, it has been grammaticalized as a non-manual marker. Furthermore, this facial expression of negation exhibits the theta oscillation (3-8 Hz) universally seen in syllable and mouthing production in speech and signing. These results provide evidence for the hypothesis that some components of human language have evolved from facial expressions of emotion, and suggest an evolutionary route for the emergence of grammatical markers.
人们认为，情感的面部表情是从用于感官调节的面部肌肉的发展演变而来的，后来又适应于表达道德判断。负面道德判断包括愤怒、厌恶和轻蔑的表情。在这里，我们研究了这样一个假设，即这些负面道德判断的面部表情进一步演变成了一种在人类语言中经常用作语法标记的否定表情。具体来说，我们表明，来自不同文化的表达否定的人使用的面部肌肉与用于表达负面道德判断的肌肉相同。然后，我们表明，这种非言语信号在言语中被用作协同发音器，并且在美式手语中，它已被语法化为非手动标记。此外，这种否定的面部表情表现出普遍存在于言语和手语发音中的θ振荡（3-8 Hz）。这些结果为某些人类语言成分是从情感的面部表情演变而来的假设提供了证据，并为语法标记的出现提供了一种进化途径。
