- Studies have revealed a relationship between the shapes of the brain and face, but the nature of this relationship has remained poorly understood.
- In a recent study, researchers used 3D facial images, genetic data, and MRIs to identify genetic regions responsible for shaping both the brain and face.
- The results revealed a much more complex face-brain relationship than previously understood, though they don't suggest that facial structure can be used to predict intelligence or behavior.
Scientists have long known there’s a genetic link between the shapes of our brains and faces. For example, research shows that people with some rare genetic disorders also have facial abnormalities, suggesting there’s a complex interplay between the structural development of the brain and face. But the exact nature of this relationship has remained largely mysterious.
Now, a new study shows that the brain-face relationship is more closely linked than previously thought. The study, published in the journal Nature Genetics, identified 76 genetic regions that affect the shapes of both the face and brain, suggesting that the two structures engage in biological “cross-talk” during development.
The study differs from past research on the brain-face relationship because it focused on brain images taken from a pool of healthy individuals, as opposed to people suffering from rare genetic conditions.
“We were astonished to find 76 genetic regions that affect both face and brain shape in the human population,” Joanna Wysocka, a professor of chemical and systems biology and of developmental biology at Stanford University, told Stanford Medicine News Center. “That’s an amazing degree of overlap, and it shows how closely these two structures affect each other during development.”
To find those overlaps, researchers from Stanford University and Belgium’s Katholieke Universiteit Leuven relied partly on prior research that identified a set of genes involved in craniofacial development. That previous research identified those genes by comparing DNA with highly detailed 3D facial images of thousands of people from the U.S. and U.K.
Armed with these insights, the researchers then analyzed MRI and genetic data from about 20,000 individuals of European ancestry. This data was obtained from UK Biobank, a biomedical database that has collected detailed genetic information from roughly half a million participants based in the U.K.
The goal was to pinpoint genetic locations that determine the shape of both the face and brain.
“Our specific focus was on variations in the folded external surface of the brain — the typical ‘walnut shape’,” Peter Claes, joint senior study author and head of the Laboratory for Imaging Genetics, said in a press release.
“We then went on to link the data from the image analyses to the available genetic information. This way, we identified 472 genomic locations that have an impact on the shape of our brain. 351 of these locations have never been reported before. To our surprise, we found that as many as 76 genomic locations predictive of the brain shape had previously already been found to be linked to the face shape. This makes the genetic link between face and brain shape a convincing one.”
The study also found that the genetic signalling pathways responsible for shaping the brain and face are enriched in parts of the genome that regulate gene activity during embryogenesis, which is the period of time during which an embryo develops and forms.
Together, the findings suggest that, just as the brain affects facial structure, so too does the face affect brain structure.
But unlike some previous studies that suggest facial appearance may reveal information about cognitive capability, the new research doesn’t show that you can look at someone’s facial structure and then reliably predict their intelligence or behavioral traits. The researchers made sure to emphasize this aspect of the study, considering there’s a history of people trying to advance racial discrimination based on psuedoscientific claims about the face-brain relationship, phrenology being one example.
“The link between the brain and the face has fascinated humans for a very long time,” Wysocka told Stanford Medicine News Center. “Many theories have tried to explain this relationship. But our study shows it would be wrong to think you can predict someone’s behavior or cognitive abilities by looking at their face. The association just isn’t there.”