According to the peak-end rule, our memory of past experience (pleasant or unpleasant) does not correspond to an average level of positive or negative feelings but to the most extreme point and the end of the episode (Kahneman & Tversky, 1999). The rule developed from findings that showed that evaluations of a past episode seem to be determined by a weighted average of ‘snapshots’ of an experience, thus neglecting its actual duration. These prototypical moments are related to the judgments made when people apply a representativeness heuristic (Frederickson & Kahneman, 1993).
Fredrickson, B. L., & Kahneman, D. (1993). Duration neglect in retrospective evaluations of affective episodes. Journal of Personality and Social Psychology, 65(1), 45-55.
Kahneman, D., & Tversky, A. (1999). Evaluation by moments: Past and future. In D. Kahneman & A. Tversky (Eds.), Choices, values and frames (pp. 2-23). New York: Cambridge University Press.