Questions In American Sign Language: A Quantitative Analysis Of Raised And Lowered Eyebrows

Although much of linguistic information in American Sign Language (ASL) is conveyed through nonmanual signals, the majority of more than 40 years of research focuses on manual signs. As a result, we are just beginning to understand the role of the face, head, and upper body in signed languages, including eyebrow movement. While researchers generally agree that eyebrows play a role in questions of examined sign languages, they disagree whether upper face nonmanuals are syntactic or prosodic and intonational. Wilbur 2000, 2003 widens the debate to suggest a layered combination in the upper face, where eyebrows represent syntax, and other upper face nonmanuals can simultaneously represent intonation and prosody. The debate over the upper face continues greatly due to a lack of quantitative data, with reliance on only qualitative movement impressions. As a result, ASL curricula do not adequately teach the role of nonmanuals, and ASL questions are often misinterpreted with serious consequences. This research presents the first quantitative analysis of eyebrows and reveals how, despite emotional state, ASL maintains linguistic distinctions between questions and statements through eyebrow height. In this study, six native Deaf participants signed yes/no questions, wh-questions, and statements, each in neutral, happy, sad, surprise, and angry states. Over 3500 measurements of consultant eyebrows were recorded from a total of 270 signed sentences. A mixed model was performed using SAS and the eyebrow levels were also charted on a timed series to see patterns. In neutral, brows for the entire sentence raise or lower, with maximums elevating 21% for yes/no questions and lowering 30% for wh-questions, but emotional questions show variable percent changes. Consistent distinctions across emotional states exist between sentence types, however, that depend on timing and spread of raised and lowered eyebrows. The data expand on the layering of upper face nonmanuals to support a theory for even more complexity on the face, where both sides of the debate have merit, as eyebrows simultaneously represent syntax, grammatical intonation, and other prosodic intonation that correlates to spoken languages. The work suggests that it is not brow furrowing that should be the focus of investigation into consistent patterns, but brow lowering. The data show a first glimpse at eyebrow height attached to signs in ASL, and new information on how raised and lowered eyebrows spread across constituents in ASL questions, with recommendations for curricula improvements. The results also show that ASL nonmanuals should not be compared to pitch in English but instead better correlate to the layering through pitch in tone languages.