Lepper is primarily responsible for the elucidation of the
overjustification effect, alongside
Richard Nisbett. With frequent collaborator
Lee Ross, and
Robert Vallone, he authored the first study to identify the
hostile media effect. With Ross and
Charles Lord he also authored an important study on
attitude change and what is now called
disconfirmation bias. With Lord he later theorized
attitude representation theory. He has also worked with
Thomas Gilovich and
Merrill Carlsmith. Lepper attended Stanford University as an undergraduate, earning a
B.A. with great distinction in psychology in 1966. He subsequently earned a
Ph.D. in
Social and
Developmental Psychology at
Yale University in 1970, returning to Stanford in 1971 as an assistant professor. Lepper became a full professor of psychology and, by courtesy, of education in 1982, and has since served as chairman of the department of psychology between 1990 and 1994, and again after 2000. He is a fellow of the
American Psychological Association and a charter fellow of the American Psychological Society. He was elected to the
American Academy of Arts and Sciences in 2004. ==References==