They grin, you bear it -- research reveals physical impact of a smile

(University of Wisconsin-Madison) Research led by Jared Martin, a psychology graduate student at the University of Wisconsin-Madison, shows that smiles meant to convey dominance are associated with a physical reaction -- a spike in stress hormones -- in their targets. On the other hand, smiles intended as a reward, to reinforce behavior, appear to physically buffer recipients against stress.
Source: EurekAlert! - Social and Behavioral Science - Category: International Medicine & Public Health Source Type: news