The Duchenne smile: emotional expression and brain physiology. II.
Level 3 - non-randomized controlled study
Non-randomized within-subject laboratory experiment (graded by design analogy for non-clinical research)
What was done
Facial expressions, electroencephalography (EEG), and self-reported subjective emotional experiences were recorded while participants individually watched pleasant and unpleasant films. Investigators compared Duchenne smiles (marked by combined activation of the muscle pulling lip corners up and the muscle orbiting the eye) against other smiles lacking orbicularis oculi activation across film conditions, EEG cerebral asymmetry metrics, and self-reported emotion.
What was found
The abstract reports directional findings without numerical values, test statistics, or effect sizes. Duchenne smiles occurred more often during pleasant films than unpleasant films and were related to measures of cerebral asymmetry and self-reported positive emotions, whereas other types of smiling were not.
Why it matters
This paper provides psychophysiological evidence linking the Duchenne smile specifically to central brain physiology and subjective enjoyment, distinguishing it from non-Duchenne smiles.
Limits
The abstract does not report the sample size, demographic characteristics of the participants, quantitative data, effect sizes, statistical significance values, or the specific direction and regions of cerebral asymmetry.
Cited by
- supports A genuine (Duchenne) smile is characterized by muscle activation and crinkling around the eyes in addition to movement of the mouth.