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Statistics LibreTexts

20.6: Smiles and Leniency

Skills to Develop

  • To study the research on effects of smiling

Research conducted by

Marianne LaFrance and Marvin Hecht 

Case study prepared by

David Lane 


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. 

Questions to Answer

Does smiling increase leniency? Are different types of smiles differentially effective? 

Design Issues

There was a single person used for all the conditions. This may limit the generalizeability of the results. 

Descriptions of Variables

Table \(\PageIndex{1}\): Description of Variables

Variable Description
Smile 1 is false smile
2 is felt smile
3 is miserable smile
4 is neutral control
Leniency A measure of how lenient the judgments were.

Data Files



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


  • Online Statistics Education: A Multimedia Course of Study ( Project Leader: David M. Lane, Rice University.