I spend hours every week staring at videos of people trying to smile. We interpret a simple smiling face in a split second, and based on the symmetry, make many assumptions about a person.
I am a facial plastic and reconstructive surgeon, with expertise in treatment of disorders of the facial nerve. The facial nerve controls the 46 tiny facial muscles that allow an array of nonverbal communication and emotional expression. Nearly everyone takes those 46 tiny muscles for granted, until an accident or illness suddenly alters their facial expression and how they interact with the world. New techniques that allow us to reconstruct a smile also remind us that a simple smile can change a life.
The face is the most important means of social communication. In less than 100 milliseconds — an eye blink takes 300 — humans can see a face, decide whether it is among the thousands stored in our memories and form an opinion. Mere millimeters of facial asymmetry can attract the attention of others and affect perception.
Responding to symmetry
In the animal kingdom, more symmetric animals are better at attracting mates, as their symmetry is thought to signal genetic quality and developmental stability. In humans, the research is more robust, if not creepy. Human body symmetry has been correlated with increased female fertility and male sperm numbers, and more symmetric faces were universally regarded by countless study groups as more attractive. But facial perception studies also show that we subconsciously regard faces with less symmetry as less honest, less employable, less trustworthy, less optimistic, less effective, less capable, less intelligent and less popular.