Eyebrows, what is really their purpose? For decades, this question has fascinated scientists. Finally, they may have found the answer.
Indeed, the eyebrows would only serve to communicate our emotions according to a recently published Anglo-Portuguese study, which arrived to this conclusion after observing the evolution of our eyebrows since prehistoric times.
In this new study, the scientists found the supraorbital region — meaning the one above the orbit of the eye – would play a significant role in communication and social connections. And that would be its only function. To arrive at such a hypothesis, scientists have gone back in time.
Through computer simulations in 3D, the scientists have virtually reconstructed the skull of Homo rhodesiensis, our 300,000 to 700,000 year old great-grandfather. He had a small but wide forehead and a prominent supraorbital ridge. The supraorbital ridge is a thickening of the bone above the eyes: the famous horizontal bone that characterizes the prehistoric man. The common explanation is that these attributes give the face extra rigidity, useful for chewing hard meats.
However, by virtually manipulating the size of the skull of the Kabwe Man as Homo rhodesiensis is commonly referred to, the researchers deduced that it had no impact on chewing. This prominent front was undoubtedly a social sign, of strength or domination, the researchers claim. As for eyebrows, they might have a role in seduction. Nonetheless it is difficult, because of huge gaps in our understanding of human evolution, to draw definite conclusions. But in the course of human evolution, the need to dominate has diminished while the need for communication and empathy has grown.
The upper face of modern man has evolved strongly over thousands of years and facial changes are undoubtedly the most significant changes in the evolutionary history of hominines according to the researchers. “The evolution of the forehead is what differentiates prehistoric man and us the most,” says Penny Spikins, an anthropologist at York University and co-author of the study. Today, the modern man — or homo sapiens — has almost lost this famous supraorbital bead and the forehead has grown larger.
This frontal bone reduction and now mobile eyebrows would be modeled on the evolution of our social interactions. The eyebrows would actually be “a biological mechanism to show others what we really feel,” says Spikins, a bit like blushing.
In the end, the eyebrows have no biomechanical function. The top of our face would be a kind of canvas to paint our emotions, with the eyebrows being a sort of evolutionary masterpiece.