Recognition of facial expressions during step-function stroboscopic presentation

Abstract

We studied the perception of human facial emotional expressions during step-function stroboscopic presentation of changing mimics. Consecutive stages of each of the six basic facial expressions were pre sented to the participants: neutral face (300 ms) — expression of medium intensity (10—40 ms) — intense expression (30—120 ms) — expression of medium intensity (10—40 ms) — neutral face (100 ms). Alternative forced choice task was used to categorize the facial expressions. The results were compared to previous studies (Barabanschikov, Korolkova, Lobodinskaya, 2015; 2016), conducted using the same paradigm but with boxcar-function change of the expression: neutral face — intense expression — neutral face. We found that the dynamics of facial expression recognition, as well as errors and recognition time are almost identical in conditions of boxcar- and step-function presentation. One factor influencing the recognition rate is the proportion of presentation time of static (neutral) and changing (facial expression) aspects of the stimulus. In suboptimal conditions of facial expression perception (minimal presentation time of 10+30+10 ms and reduced intensity of expressions) we revealed stroboscopic sensibilization — a previously described phenomenon of enhanced recognition rate of low-attractive expressions (disgust, sadness, fear and anger), which has been previously found in conditions of boxcar-function presentation of expressions. We confirmed the similarity of influence of real and apparent motion on the recognition of basic facial emotional expressions.