What Does Your Face Say About Your Brain?

New parents enjoy identifying familiar features of themselves in the faces of their newborns. “She has her mother’s eyes,” or “he has his father’s smile.” Is that as far as it goes? Or do the features of the face also predict the nature of the mind?

The ancient Greeks thought that it was possible to assess personality from facial appearance. The practitioners of the art of Physiognomy claim that you can tell someone’s personality by examining the shape of the facial features. Are these claims true? The lack of credible evidence against these appealing claims has allowed them to continue.

What does the face tell us about the brain? Is it possible to predict someone's behavior based on their facial features? A recent study investigated whether a relationship exists between brain shape and facial features.

When we think of brain shape, the first thing that comes to mind is the series of ridges and valleys that are formed by the cerebral cortex. This layer is responsible for most of our cognitive functions and distinctive personality traits.

The complex folding patterns vary between individuals. There are, of course, some highly consistent patterns across all humans—the ridges that occur in the back half of the brain, for example, process sensory information, while those in the front half of the brain process movement and the planning of movement. However, the details of the folding and the shape of the different regions are as unique as the face that sits in front of the brain. I have dissected hundreds of brains and can attest to their incredible variability. (If you would like to read more about the brain, check out my book The Brain: What Everyone Needs to Know.)

The development of the brain and face is highly integrated for three reasons: they have a shared developmental lineage, they develop close to each other, and they talk (chemically) to each other during development. Studies have shown that after the major parts of the brain develop, but before the most frontal part of the brain grows, some cells break off from the brain and migrate forward to give rise to the face. This phenomenon was first noticed in 1964 to describe the correlation between the severity of brain and face malformations.

The current study mapped genetic links between features of individual faces and brain shape in a large population of people without neurological disorders. They identified the location of 472 genes that influence the shape of the brain; 76 of these brain-shape genes were also linked to the shape of the face. Thus, there are at least 76 overlapping genetic locations that link variations in brain shape and craniofacial skeletal development.

What the researchers didn't find was just as important.

The study found no evidence that this genetic overlap predicts someone's behavioral or cognitive traits. The shape of the face also does not predict the risk for degenerative disorders, such as Alzheimer's disease. The authors concluded that it is impossible to predict someone's behavior based on their facial features. There is no genetic evidence for a link between someone's face and that individual's behavior.

These findings debunk persistent pseudoscientific claims about what the face reveals about us. The risk of developing a neuropsychiatric disorder is not written on your face. That’s worth smiling about.