The most noticeable difference between the modern human face and that of the hunter-gatherers, who lived on Earth over 200,000 years ago, is the forehead. While we now have flat, smooth foreheads with visible eyebrows, our ancestors sported a pronounced brow ridge. Experts have always believed that the thick rim, and the evolution to the beautiful tufts of facial hair, served a physiological function. Now, a team of scientists from UK’s University of York and Portugal’s Universidade do Algarve suggest the distinct facial features help with our social relationships.