Did you know that genuine smiles not only utilize the muscles of the mouth but also those of the eyes? They are known as Duchenne smiles, in honor of research by a French neurologist: Guillaume-Benjamin-Amand Duchenne (de Boulogne) who lived from 1806 to 1875. Tara L. Kraft and Sarah D. Pressman of the University of Kansas studied whether covertly manipulating positive facial expressions would influence cardiovascular and affective responses to stress. Study participants were asked to complete stressful tasks(e.g., tracing a star using their nondominant hands) while holding chopsticks in their mouths in a manner that produced a Duchenne smile, a standard smile, or a neutral expression. Findings revealed that all smiling participants, regardless of whether they were aware of smiling, had lower heart rates during stress recovery than the neutral group did, with a slight advantage for those with Duchenne smiles. It appears that there are physiological and psychological benefits to be gained from maintaining a positive facial expression during stress.