The Mysterious Noh Mask: Contribution of Multiple Facial Parts to the Recognition of Emotional Expressions

Abstract

BackgroundA Noh mask worn by expert actors when performing on a Japanese traditional Noh drama is suggested to convey countless different facial expressions according to different angles of head/body orientation. The present study addressed the question of how different facial parts of a Noh mask, including the eyebrows, the eyes, and the mouth, may contribute to different emotional expressions. Both experimental situations of active creation and passive recognition of emotional facial expressions were introduced.Methodology/Principal FindingsIn Experiment 1, participants either created happy or sad facial expressions, or imitated a face that looked up or down, by actively changing each facial part of a Noh mask image presented on a computer screen. For an upward tilted mask, the eyebrows and the mouth shared common features with sad expressions, whereas the eyes with happy expressions. This contingency tended to be reversed for a downward tilted mask. Experiment 2 further examined which facial parts of a Noh mask are crucial in determining emotional expressions. Participants were exposed to the synthesized Noh mask images with different facial parts expressing different emotions. Results clearly revealed that participants primarily used the shape of the mouth in judging emotions. The facial images having the mouth of an upward/downward tilted Noh mask strongly tended to be evaluated as sad/happy, respectively.Conclusions/SignificanceThe results suggest that Noh masks express chimeric emotional patterns, with different facial parts conveying different emotions This appears consistent with the principles of Noh which highly appreciate subtle and composite emotional expressions, as well as with the mysterious facial expressions observed in Western art. It was further demonstrated that the mouth serves as a diagnostic feature in characterizing the emotional expressions. This indicates the superiority of biologically-driven factors over the traditionally formulated performing styles when evaluating the emotions of the Noh masks.

Shadows Alter Facial Expressions of Noh Masks

“…These results show trends opposite to the rules of Noh, consistently with the previous findings using vertically tilted Noh mask images [4]–[6], [9]. The present data thus suggest comparable effect of tilting angles, by simply manipulating the shadows of the Noh mask images.…”

“…Specifically, the corners of the lips are pulled up for the downward tilted Noh mask, which are elements of a happy expression [5]. This seems to explain why downward tilted masks are recognized as happy (and vice versa), because the shape of the mouth serves as a distinctive feature in the judgment of emotions [9]. Further, the fact that the attached shadows of the smiling mouth made the mask look happy appears consistent with the smile of Mona Lisa, which is more apparent in the low spatial frequency [17].…”

“…For each of the four types of Noh masks, images having happy and sad facial expressions were created by modifying the original neutral facial images [9]. FaceTool, a software for processing facial expressions, was used.…”

“…Nishimura et al [4] used images of either the Noh mask alone, or the mask together with the body, and revealed that pictures with small downward inclinations were recognized as sadder, while those with larger downward inclinations as happier. Miyata et al [9] further demonstrated that different facial parts convey different emotions in a Noh mask, and that among the facial parts the mouth serves as a diagnostic feature in the categorical judgment of emotions. These preceding studies are in agreement that the vertical head/body orientation of the actor influences the recognition of emotions (see also [10]–[12]).…”

“…That is, a Noh stage is characterized by its darkness, reflecting the lighting conditions of the ancient ages [21]. Small inclination of the actor’s head and the body during the drama conveys multiple subtle emotional changes [4], [9]. Lighting from above naturally causes many shadows at the lower half of a Noh mask, whereas lighting from below results in wide shadowed areas at its upper half.…”