AU6 — Cheek Raiser
The Action Unit produced by the orbicularis oculi (pars orbitalis), which raises the cheeks and produces crow's-feet around the eyes.
AU6 is the upper-face Action Unit most strongly associated with authentic positive emotion. It is partially involuntary, which is what makes it useful as a marker for genuine versus performed expression.
In FACS-based emotion analysis, AU6 combined with AU12 is the canonical signature of a Duchenne smile. AU6 alone can also signal squinting in bright light or concentration, so it is always interpreted in context.
Related terms: action unit, duchenne smile, au12 lip corner puller, facial action coding system
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