Abstract
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 facial 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, in Experiment 1, we show that people from different cultures expressing negation activate the same facial muscles as those employed to express negative moral judgment. This newly discovered expression of negation (which we call the "not face") was consistently identified in over 400 spoken and signed sentences in English, Spanish, Mandarine Chinese and American Sign Language (ASL). In Experiment 2, we further our previous analysis to show that this nonverbal signal is used as a co-articulator in spoken languages and that, in ASL, it has been grammaticalized as a non-manual marker. Finally, in Experiment 3, we demonstrate that this facial expression of negation exhibits the theta oscillation (3-8 Hz), which is a universal property in syllable and mouthing production in speech and signing (Chandrasekaran et al., 2009; Wilbur & Nolen, 1986). These results hence provide the first evidence for the hypothesis that some components of human language have evolved from sensory regulation and the expression of emotion, providing a possible evolutionary route for the emergence of grammatical markers in human language.
Meeting abstract presented at VSS 2016