(Bk Business) Carol Kinsey Goman Ph.D.-The Nonverbal Advantage_ Secrets and Science of Body Language at Work -Berrett-Koehler Publishers (2008)

Chapter 4: Face to Face
73
Genuine smile
Smile that doesn’t
reach the eyes
only affects the corners of the mouth but changes the entire
face: the eyes light up, the forehead wrinkles, the cheek muscles
rise, skin around the eyes and the mouth crinkles, and
finally the mouth turns up.
Another signal of a genuine smile (and one that is almost
impossible to fake) is a lowering of the inner corner of the
eyebrows. The absence of lowered eyebrows is one reason
why false smiles look so strained and stiff.
Real smiles are also difficult to fake when we feel negative
emotions. The polite smile offered by a bored salesclerk, or
by someone hearing a joke for the hundredth time, pulls up
the lips but, literally, stops there.
If you look at a photo of someone smiling and cover their
lips, their eyes reveal everything about their real feelings.
Mo Williams, an illustrator and author of children’s books,
says that if he draws a face with unhappy eyes and a smiling
mouth, it is a picture of a sad face. So there you have it! The
truth of a smile is in (and around) the eyes.