PERCEPTION OF FACIAL EXPRESSIONS DURING MASKING AND APPARENT MOTION

We studied the impact of apparent motion and masking on basic facial expressions recognition during stroboscopic movement. In Experiment 1, observers (N=53) recognized facial expressions using alternative forced choice of basic emotion labels, in Experiment 2 subjects (N=7) provided free description of facial expressions. Facial expressions were presented for 50, 100 or 200 milliseconds, sandwich-masked by neutral face (series 1), scrambled face (series 2), or without masking (series 3). In series 1, the images sequence of the same identity with different expressions appeared as continual expression change, accompanied by head movements. In series 2 and 3, the face images appeared static. The study showed that context type, expression type and presentation time influence facial expressions recognition and change their categorical structure. Compared to no-mask presentation (series 3), masking and apparent motion reduce the recognition rate, but their influence is based on different mechanisms. Experiment 2 revealed the mechanisms of reduced facial expression recognition in conditions of masking and apparent motion.