You probably already know the function of your eyebrows – they divert sweat and raindrops away from your eyes. However, they are also extremely expressive – we can guess pretty accurately what other people are feeling just by looking at their eyebrows. Now scientists from the University of York say that our eyebrows could have been a major benefit for survival.
Humans are the last surviving hominin, Neanderthals are long gone. In fact, while they were slowly dying out, we were dominating the planet. And conditions were rough. So how did we manage to survive while other species came and went? There is no simple explanation, but eyebrows might have been a key. You see, you can tell the emotion of the smiley face scribble on a piece of paper just by looking at his eyebrows – they are really that important. However, our ancestors did not have such expressive eyebrows. In fact, their eyebrows had little to no mobility and were characterized by a prominent bone ridge.
Scientists used 3D modelling techniques to create a digital model of the Kabwe 1 skull. It does have a prominent eybrow ridge, but scientists managed to shave it off to see what effect it would have on the mechanical performance of the bones. At it didn’t have any – this ridge did not participate in distribution of biting forces. It might have been useful to protect the face (as a bumper), but scientists argue that social functions were more important. But what kind of social functions could eyebrows have?
Now you know eyebrows are used subconsciously to express emotions. In fact, when you’re pretending to be angry, you move your eyebrows down and closer together and when you are surprised, you raise them high. But eyebrows can communicate a huge variety of emotions and it was very important when humans started forming social groups. You cannot know every member of a large group, so how do you know what he is thinking and if you can trust him? Unless you have mind reading powers, you will have to guess by facial expression.
And so mobile eyebrows could have helped humans to form social bonds which were crucial for our survival. Dr Penny Spikins, co-author of the paper, said: “While our sister species the Neanderthals were dying out, we were rapidly colonising the globe and surviving in extreme environments. This had a lot to do with our ability to create large social networks – we know, for example, that prehistoric modern humans avoided inbreeding and went to stay with friends in distant locations during hard times”.
It is also interesting that other studies showed that people who had botox injected into their foreheads and as result have less mobile eyebrows are less able to empathise and identify with the emotions of others. So it is better to let eyebrows be, because they might as well be our main evolutionary advantage.
Source: University of York