Question

what is a duchenne's smile​

Answer 1

Explanation:

All smiling involves contraction of the zygomatic major muscles, which lifts the corners of the mouth. But a Duchenne smile is characterised by the additional contraction of the orbicularis oculi, crumpling the skin around the eyes into crows' feet.

Answer 2

A Duchenne smile is the type of smile that involves your eyes,  as well as involves contraction of both the zygomatic major muscle (which raises the corners of the mouth)