Smiles have a powerful effect on us. The human brain prefers happy faces, and we can spot a smile at 300 feet the length of a football field. Smiling not only stimulates your own sense of well being it also tells those around you that you are approachable and trustworthy.Research from Duke University proves that we like and remember those who smile at us and shows why we find them more memorable. Using functional magnetic resonance imaging (fMRI), the Duke researchers found that the orbitofrontal cortices (a reward center in the brain) were more active when subjects were learning and recalling the names of smiling individuals. Most importantly, smiling directly influences how other people respond to you. When you smile at someone, they almost always smile in return. And, because facial expressions trigger corresponding feelings, the smile you get back actually changes that persons emotional state in a positive way.