Duchenne Smile Vs. Nonduchenne Smile

The most recognizable facial expression of emotion is the smile of happiness. Yet not all smiles are created equally. In particular, Duchenne smiles are smiles that pull up the lip corners diagonally and contracts the band of mushcles that circle the eye to create crow's feet and raise the cheeks. This smile expresses true enjoyment. Usually when we smile for social reasons and not genuinely happy, we only use the lips and not the band of mushcles around the eye. This smile is referred to as non-Duchenne smile

.