YOU wrinkle your nose and squint if you see a dead rat in the road, but you open your eyes and mouth wide if you see a live one in your bedroom. Why is that?
Facial expressions are usually thought of as simple tools of communication, but in his book The Expression of the Emotions in Man and Animals Charles Darwin proposed that they may prepare us to react to situations when he noticed that some expressions seemed to be used across cultures and even species. Now Joshua Susskind and his colleagues at the University of Toronto, Canada, have…
