Have you ever been out and about, perhaps tackling the Christmas shopping list, and felt a bit thirsty? You buy a drink—say, one that comes in a plastic bottle—and quench your thirst, only to find ...

More than 50 years ago, University of Minnesota social psychologist Leon Festinger and two colleagues wrote these words in the opening to “When Prophecy Fails,” their groundbreaking case study on ...

A police officer once told me that most crimes are solved because the criminal mind, as he put it, was “stuck on stupid.” At Stanford back in the late ’50s, Leon Festinger developed theories and tests ...

In the classic study on cognitive dissonance by social psychologist Leon Festinger, subjects were split into two groups that had to perform monotonous tasks for a long stretch of time — placing 12 ...