A ‘Duchenne smile’ is a powerful way of striking up a new relationship, a new study finds. People are highly tuned to the Duchenne smile, which involves upturned lips and crinkly eyes. And they can easily spot a fake smile, which tends to involve only the mouth and not the eyes.The research tested how much people are aware of each other’s emotions, whether negative or positive. It found that people were more aware of positive emotions in other people than negative. Read the story.