Why Do We Have Eyebrows?

If you’ve ever wondered why we have eyebrows, it’s unlikely that you thought communication was the reason. Physically, eyebrows are there to help keep our eyes clean and clear. They move wetness from sweat and rain away from our eyes so we can maintain our sight. Eyebrow hairs grow outward toward the sides of the face, which helps direct any moisture away from the eyes and toward the side of the head. Eyebrows can also reduce the amount of light that gets into our eyes and keep dirt away from them as well. Eyebrows are also an important part of human expression and communication. They allow us to show our emotions. One raised eyebrow expresses skepticism or interest, while two raised eyebrows can express surprise. Beyond looks and emotions, eyebrows are also important for facial recognition. In a 2003 study, scientists asked a group of people to identify the faces of 50 famous people. The scientists manipulated the photos so that they would either have no eyes or no eyebrows. Subjects could still identify the famous faces 60% of the time when they lacked eyes. However, when the faces lacked eyebrows, subjects could only identify them 46% of the time. That indicates that eyebrows are just as important — or maybe more important — than eyes in allowing us to recognize faces.