@CNN: Modern humans evolved to have a smooth forehead with very mobile, expressive and hairy eyebrows rather than permanent brow ridges. So why did this happen? Researchers think it might have helped us be more social. https://t.co/Yb9zKWE4PZ https://t.co/AKzxYD1ziF

@CNN: Modern humans evolved to have a smooth forehead with very mobile, expressive and hairy eyebrows rather than permanent brow ridges. So why did this happen? Researchers think it might have helped us be more social. https://t.co/Yb9zKWE4PZ https://t.co/AKzxYD1ziF