This refers to a phenomenon wherein people tend to judge an experience primarily based on how they felt during the most intense point of the experience and the eventual outcome. In other words, people’s judgment of an experience does not depend on the average level of pleasure or displeasure that they were exposed to during the period of the experience. The peak-end rule, which has been used to explain the irrationality involved in various forms of human behaviour, and applied to influence such behaviour, was first studied by American psychologists Daniel Kahneman, Barbara Fredrickson and their colleagues in 1993.