Viewpoint Dependent Facial Expression Recognition Japanese Noh Masks and the Human Face

With certain masks used in Japanese Noh drama the apparent facial expression is a function of the vertical viewing angle. Rotation in depth produces changes in the retinal image of the face which viewers may confound with the distortion of features due to muscular action. In particular, as the mask is tilted forward it appears to smile, and as it is tilted backwards it appears sad. We explored this effect in two experiments with a Noh mask and one with a 3-D model of a laser-scanned human face. Separate British and Japanese subject pools were used to investigate cross-cultural effects. The results confirmed a systematic relationship between vertical angle of view and judged affect. For the Noh mask the effect was culturally moderated, whereas for the human face there was no significant effect of of culture. These results are discussed and interpreted in terms of perceptual strategies for processing familiar and unfamiliar faces.