Abstract: A computing system identifies video data capturing an expressor depicting facial behavior. The computing system analyzes the video data to determine a type of emotion exhibited by the expressor in the video data by identifying appearance changes produced by movements of facial muscles in the video data; and determining timing characteristics of the movements of the facial muscles in the video data, the timing characteristics indicating whether the facial behavior depicted by the expressor is an authentic expression or fake expression. The computing system generates a classification of the type of emotion exhibited by the expressor based on the movements of the facial muscles and the timing characteristics of the movements. The computing system outputs the classification.