Psychological scientists Tara Craft and Sarah Pressman from the University of Kansas embarked on a study to find out the relationship between certain kinds of smiles and the ability to recover from stressful episodes. Researchers often classify two types of smiles; standard smiles where only the mouth shapes the smile, and genuine or Duchenne smiles where the muscles around the mouth and eyes shape the smile (Duchenne used electrophysiology to show how genuine smiles use the muscles around the eyes).
There were two phases to the study that had 169 participants. The first was the training stage where the volunteers were taught the two different smiles. The second, or testing phase, had volunteers using the trained smiles while they participated in stressful activities. The participants heart rates were monitored during the activity and it was found that those with genuine smiles had lower recovery heart rates than those with neutral facial expressions. The participants that had standard smiles also had an improved recovery rate over the neutral group. The conclusion: Smiling during brief periods of stress, whether you are happy or not, may help reduce the body’s stress response.