Bystander intervention in a Crime: The Effect of a Mass‐media Campaign1

Two field studies investigated bystander intervention by witnesses to a staged shoplifting in a University bookstore. In the first study, a mass‐media campaign was successful in communicating information and altering behavioral intentions, but not in increasing actual intervention behavior. A second study attempted to determine whether the low report rate and the relative ineffectiveness of the campaign to alter this rate was due to in‐group loyalty between students. The results indicated that although students differentially perceived a nonstudent shoplifter, there was no increase in intervention.