The Noh mask test for analysis of recognition of facial expression.

A preliminary study on the Noh mask test for analysis of recognition of facial expression was performed. The present study was conducted on 15 normal subjects (mean age: 32 years, SD 9.7 years) as the first step to test for the differences between psychiatric patients and normal subjects. Stimuli were created by photographs of 15 Noh masks at different vertical angles. Subjects were given 12 tasks (12 emotion items), and each task consisted of 15 trials (15 Noh mask images). In each trial, the subject viewed a colour monitor, and was shown an emotion item, followed by a Noh mask image. The subject pressed either the yes or no key to indicate whether the Noh mask image expressed the emotion item. The subject's response and reaction time to each Noh mask image showed no deviation, although the subject's response and reaction time to each emotion item showed some deviation. As the vertical angle of the Noh mask changed, normal subjects recognized all emotion items except the 'uncanny' expression. Factor analysis of the 15 Noh mask images produced three factors, and the analysis of 12 emotion items produced five factors. Thus, the Noh mask test was simplified to nine images and nine items. Further developments of the Noh mask test may include the evaluation of the dysfunction of perception on delicate facial expression in psychiatric patients.