The Duchenne Smile

A genuine smile and a social smile use different muscles — and the eyes are the tell.

Genuine (Duchenne)

AU6 + AU12. Eyes narrow, cheeks rise, crow's feet appear at the outer eye corners. The orbicularis oculi engages along with the zygomaticus major.

Social

AU12 alone. The mouth moves — corners pull up — but the eyes stay dead. No narrowing, no crow's feet.

Drill: In a mirror, alternate the two smiles deliberately. Hold a social smile, then add the eye squeeze for the genuine version. The AU6 difference — eye narrowing and crow's feet — is the tell. Most people can't fake the AU6 eye-narrowing on demand, though a trained minority can — so treat it as a strong tell, not an absolute.