Temporal dynamics of pain smile

Abstract

In temporal dynamics of facial expressions it has been suggested that fake and genuine expressions may be distinguished mostly through differences in their temporal pattern. Smiles with onsets and offsets longer and apex of brief duration are considered genuine smiles. Smiles with onsets and offsets more briefer and long apex duration are considered faked smiles. Using video recordings of facial pain expressions provided by the application of a Cold Pressor (spontaneous, simulated and inhibited conditions) and subject to FACS coding, AUs 4, 10, AU 12, were additionally analyzed on a number of timing features, namely: onset time; apex duration; onset-to-apex duration; apex-to-offset duration; offset time. Our results indicate that all people tend to simulate in the same temporal standard (decrease of standard error).The simulation of AU10 apex is also similar. AU12 decreases duration in simulated condition.