Dale Carnegie stated that smiling helps win friends and influence people. Research on the effects of smiling has backed this up and shown that a smiling person is judged to be more pleasant, attractive, sincere, sociable, and competent than a non-smiling person.

There is evidence that smiling can attenuate judgments of possible wrongdoing. This phenomenon termed the "smile-leniency effect" was the focus of a study by Marianne LaFrance & Marvin Hecht in 1995. These researchers were interested in several questions: (a) Does smiling really increase leniency? (b) Are different types of smiles differentially effective? and (c) Why does smiling increase leniency? (If, in fact, it does.)

This case study currently only covers questions (a) and (b). The viewer is referred to the following article for information on Question c.

LaFrance, M., & Hecht, M. A. (1995) Why smiles generate leniency. Personality and Social Psychology Bulletin, 21, 207-214.