Gummy smiles:

The pervasiveness of the leftist gummy smile is noteworthy.

(pic related) Alexandria Ocasio-Cortez show both the shoulder scrunch-neck extension gesture and the gummy smile.

Hypothesis:

This anon thinks there is a contagious quality to these exaggerated gestures. It seems as if some people will smile like this until the target is forced to smile back. The vector could be a social superior, and the return smile could be done repeatedly in appeasement. Different muscles could be used as they are in sincere vs insincere smiles. Over time the appeasement smiles could become habit, which would explain the gummy smile phenomenon.

The degree of arbitrary personal authority enjoyed by superiors in a particular social group would explain why some groups have gummy smiles and some don't.

The gummy smile at the same time convey an element of self defense, as if the person is cornered and showing teeth against an aggressor.

Mateo Sol says in Loner Wolf:

Guillaume Duchenne de Boulogne did electrical experiments with the heads of people executed by guillotine.

He discovered two sets of muscles are the major players in smiles.

"the zygomatic major muscles which run down the side of the face and connect to the corners of the mouth, and the orbicularis oculi muscles that pull back the eyes. The zygomatic majors pull the mouth back exposing the teeth and enlarging the cheeks, the orbicularis oculis however make the eyes narrower and cause wrinkles in the corners."

The zygomatic majors are more under conscious control than the orbicularis oculis.

When we smile and say cheese, we are engaging the zygomatic majors.

The difference is the distinction between sincere and insincere smiles.

But he doesn't mention gummy smiles.

Okay, people actually get surgery for gummy smiles.

Botox helps, and lip lengthening by a plastic surgeon seems preferable to maxillofacial surgery.

From Dr. Farnoosh:

https://www.thetotalsmile.com/gummy-smile-correction-faq/

The gummy smile technique Dr. Farnoosh offers ranges in price from $4,000 to $10,000.

In addition to its physical advantages, gummy smile surgery is considerably more affordable than jaw surgery [breaking and rearranging the jaw], which often costs between $35,000 and $40,000.

Research is ongoing.

anon