How we change what others think, feel, believe and do

Smiling

Techniques > Using body language > Smiling

The physiology of the smile | The genuine smile | False smiles | See also

When you smile in a genuine way, it happens using the unconscious brain where emotions are controlled - you are genuinely happy in some way.

The physiology of the smile

There are various parts of the face that change when someone smiles:

The mouth stretches and may well show teeth.
The muscles that move the cheeks contract, making the eyes crease up and eyebrows dip slightly.
Lines appear around the eyes.
The eye cover fold (the bit between the eyebrow and the eyelid) moves downward.
The end of the eyebrows dip very slightly

The genuine smile

The genuine smile, also known as Duchenne smile indicates real happiness or amusement. In particular it is different from the false smile in the use of the cheeks and the muscles above the eyes (the orbicularis oculi). Eyelids may fold more and the outer ends of the eyebrows may dip.

It is not the entire orbicularis oculi, actually, that is involved, only the outer portion, the orbicularis oculi, pars lateralis.

A genuine smile tends to last for 0.5 to 4 seconds (so believe a quick smile over a longer one). It is often asymmetric and usually larger on the right side of the face.

False smiles

False smiles can be remarkably difficult to detect, especially when done by a 'pro'. Yet they are distinctly different.

Watch for excessive symmetry and missing lines around the eyes as the orbicularis oculi are not used, although these can sometimes be forced with strong muscle movement.

Watch for the eye cover fold: it is very difficult to control this. Also the ends of the eyebrows dipping is difficult to fake.

False smilers may lower the jaw to create a D-shaped open-mouthed smile. This is easier to do and pulls attention away from the eyes.