Eyebrow movements and vocal pitch height: evidence consistent with an ethological signal.

When asked to sing a high pitch, people produce a facial expression that is judged more friendly compared with singing a low pitch [Huron et al. (2009). Empirical Musicology Rev. 4(3), 93-100]. This effect was observed even when judges viewed only the face above the tip of the nose, and implies a relationship between pitch height and eyebrow height. In the current study, we examine the reverse relationship. Thirty-one participants were asked to read aloud standard texts while holding their eyebrows in a raised, neutral, or lowered position. Average F0 was found to correlate positively with eyebrow position, with higher vocal pitch associated with higher eyebrow placement. However, manipulating eyebrow placement produces a considerably smaller effect (on pitch) compared with the effect of manipulating pitch (on eyebrows). Results are discussed from the perspective of ethological signals [Lorenz (1939). Zool. Anz. 12, 69-102].