Peak-end rule

In a classic experiment, people held a hand in painfully cold water at 14 °C for 60 seconds, and on another occasion for 90 seconds, where the last 30 seconds were slightly less cold. Asked which trial they would rather repeat, 69% chose the longer one: more pain overall, but a better ending. The pattern holds outside the lab. In a randomized trial with 682 colonoscopy patients, those whose procedure ended with a short, milder extra interval rated the whole experience as less unpleasant and were somewhat more likely to come back for a repeat colonoscopy in the following years. A 2022 meta-analysis of 174 effect sizes found a large effect of peaks and endings on how people rate experiences, and almost no effect of duration. In products, the moments that shape memory, and whether people come back, are the high point and the last screen.