The Perception of Facial Expressions from Two-Frame Apparent Motion

We examined the contribution of motion information in perceiving facial expressions using point-light displays of faces. First, we established the minimum number of feature points necessary for the perception of facial expression from a single image. Next, we examined the effects of motion with a stimulus using an insufficient number of dots. We used two conditions. In the motion condition, the apparent motion was induced by a preceding neutral face image followed by an emotional face image. In the repetition condition, the same emotional face image was presented twice. The performance was higher in the motion condition than in the repetition condition. This advantage was reduced by inserting a white blank field between the neutral and emotional faces thus confirming that the improvement was due to the motion.