Editing Mark Lepper (section)

==Life==
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 [[Bachelor's degree|B.A.]] with great distinction in psychology in 1966. He subsequently earned a [[Doctor of Philosophy|Ph.D.]] in [[Social psychology|Social]] and [[Developmental psychology|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.<ref>{{cite web |title=Mark R. Lepper |url=https://www.amacad.org/person/mark-r-lepper |website=amacad.org |publisher=[[American Academy of Arts and Sciences]] |language=en |date=19 May 2025}}</ref>