MORE ABOUT BROWS A Cross-Linguistic Study via Analysis-by-Synthesis

In a seminal paper, Ekman (1979) remarks that brows can play an accentuation role (e.g., to signal focus). However, the literature about eyebrows is inconclusive about their exact role and as a consequence there is no agreement among developers of embodied conversational agents about their precise timing and placement. In addition, it is unclear whether eyebrow movements perform the same role in different languages. In this chapter, an analysis-by-synthesis technique is used to find out what the role of eyebrow movements is for the perception of focus and to see whether this role is the same across different languages. Three experiments are performed, both for Dutch and Italian, investigating where subjects prefer eyebrow movements, whether brows influence the perceived prominence of words and whether they are used in a functional way when subjects interpret utterances. The results for Dutch and Italian are indeed different, but it is argued that these differences can be reduced to prosodic differences between the two languages. The advantages and potential limitations of studies via analysis-by-synthesis are discussed, and an approach to compensate for the limitations is offered.