Experimental Design
Subjects in the experiment were asked to assume the role of a student member
of a college disciplinary panel and judge a student accused of cheating. Each
subject received a file that contained (a) a letter ostensibly from the chairperson
of the Committee on Discipline, (b) a summary of the evidence, (c) background
information on the suspect including prior academic performance and a color
picture portraying one of the four facial expressions, and (d) rating scales
to indicate the judgments. Subjects answered five questions about the likelihood
of the suspect's guilt and how severe the punishment should be. These questions
were combined into one "leniency score."
Four groups of subjects were tested. Each group saw one of the three types of
smiles or a neutral-expression control. Subjects from a sample of 136 college
students were randomly assigned to the four conditions with the constraint that
there was an equal number of subjects (34) in each group. The three types of
smile are illustrated on a separate page. These
types of smiles have been studied and categorized by Paul Ekman. (See his book:
Telling lies: Clues to deceit in the marketplace, politics, and marriage.
published by Norton Publishing in 1985.)
The pictures used as stimulus materials were photographs of two college sophomore
women. Each was photographed displaying each of the four facial expressions.