text: Using this on humans isn't a good thing. If they want to keep an emotion hidden then I don't think it is a good idea to uncover it. How can the world be a positive place if the happy people who made you happy weren't actually happy. What if that person had a death of a family member and wanted to keep it a secret but some random person starts snooping around and tells everyone that that person isn't actually happy. Since the article can tell a fake smile from a real smile it could possibly happen. Now if the person gives you consent then it is fine but nobody should be able to read someones emotion.