From Sinatra to Katy Perry, celebrities have long sung about the power of a smile — how it picks you up, changes your outlook, and generally makes you feel better. But is it all smoke and mirrors, or is there a scientific backing to the claim? Groundbreaking research confirms that the act of smiling can trick your mind into being more positive, simply by moving your facial muscles.From Sinatra to Katy Perry, celebrities have long sung about the power of a smile — how it picks you up, changes your outlook, and generally makes you feel better. But is it all smoke and mirrors, or is there a scientific backing to the claim? Groundbreaking research confirms that the act of smiling can trick your mind into being more positive, simply by moving your facial muscles.