Facial expression and vocal pitch height: Evidence of an intermodal association.

Forty-four participants were asked to sing moderate, high, and low  pitches while their faces were photographed. In a two-alternative forced choice task,  independent judges selected the high-pitch faces as more friendly than the low-pitch  faces. When photographs were cropped to show only the eye region, judges still rated the high-pitch faces friendlier than the low-pitch faces. These results are consistent with prior research showing that vocal pitch height is used to signal aggression (low pitch) or appeasement (high pitch). An analysis of the facial features shows a strong
correlation between eyebrow position and sung pitch—consistent with the role of eyebrows in signaling aggression and appeasement. Overall, the results are consistent with an inter-modal linkage between vocal and facial expressions.