The Peak|End Rule [en]
A psychological Power Law called the Peak | End Rule. First discovered by Nobel-prize winning psychologist Daniel Kahneman, the principle states that "what we remember about the pleasurable quality of our past experiences is almost entirely determined by two things: how the experiences felt when they were at their peak (best or worst), and how they felt when they ended. This ‘peak-end’ rule is what we use to summarize the experience, and then we rely on that summary later to remind ourselves of how the experience felt." Simply put, our entire recollection of an event, a period of time, a relationship or even a person can come down, in large measure, to how we felt at the zenith or nadir of the experience and especially at its’ conclusion.
