Duchenne Smile
A genuine smile of enjoyment that activates both AU6 (cheek raiser) and AU12 (lip corner puller).
Named for 19th-century French neurologist Guillaume Duchenne, the Duchenne smile is the FACS-defined signature of authentic positive emotion. The orbicularis oculi muscle — responsible for AU6 — is largely involuntary, which is why eye-crinkle activation is considered the hallmark of a real smile.
Polite, masking, or performative smiles typically show AU12 in the absence of AU6. Distinguishing the two reliably is one of the foundational applications of FACS-based facial analytics in coaching, therapy, and interview assessment.
Related terms: action unit, au6 cheek raiser, au12 lip corner puller, facial action coding system
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