Facial expressions play a powerful role in social interactions from birth to adulthood. Fear, joy, anger — all our emotions are articulated and understood thanks to universal codes. Common sense sees this enterprise as an act of imitation: children imitate their parents by reproducing the facial expression linked to each emotion. But if this is the case, does the same hold true for people who were born blind? Researchers analyzed 21 scientific studies conducted between 1932 and 2015 to find the answer.