Peak-end Rule
Judging experiences by their peaks and endings, not totals
What is it?
The peak-end rule, identified by Daniel Kahneman and colleagues, describes how we remember and evaluate experiences based not on their total or average, but on their most intense moment (the peak) and how they ended. Duration matters surprisingly little—a phenomenon Kahneman called "duration neglect." In one experiment, people who held a hand in painfully cold water preferred to repeat a longer trial that ended with a slightly less painful stretch over a shorter one; studies of colonoscopy patients likewise found that memories of the procedure tracked its worst and final moments more than its length. This has practical implications for experience design. A vacation with one spectacular day and a pleasant last day may be remembered more fondly than a uniformly good vacation. Customer experiences, medical procedures, negotiations, and even relationships are often judged by their peaks and endings. The rule explains why endings matter so much in movies, why "saving the best for last" can be effective, and why a single terrible experience can outweigh many good ones. Designing for the peak-end rule means creating memorable high points, ensuring positive endings, and recognizing that duration is less important than how an experience feels at its most intense and final moments.
Example
Rating a project as successful because it ended well, despite months of problems. Remembering a vacation by its best day and last day. A great dessert redeeming an average meal.
References
Kahneman, D., Fredrickson, B. L., Schreiber, C. A., & Redelmeier, D. A. (1993). When More Pain Is Preferred to Less: Adding a Better End. Psychological Science, 4(6), 401-405.
Redelmeier, D. A., & Kahneman, D. (1996). Patients' Memories of Painful Medical Treatments: Real-Time and Retrospective Evaluations of Two Minimally Invasive Procedures. Pain, 66(1), 3-8.
Fredrickson, B. L., & Kahneman, D. (1993). Duration Neglect in Retrospective Evaluations of Affective Episodes. Journal of Personality and Social Psychology, 65(1), 45-55.
How to Prevent It
Doxa uses AI and can make mistakes. How it's built
Am I judging the whole experience or just memorable moments?
Would I still rate it this way if it had ended badly?
How long did the good/bad parts actually last?
Is my memory of this experience accurate or distorted?
Am I overweighting the ending in my evaluation?
Keep records throughout an experience, not just at the end.
Before a project review, list the key moments month by month, not just the launch.
Calculate averages and totals, not just peaks and ends.
Design endings deliberately when creating experiences.
Ask for moment-by-moment ratings when evaluating experiences.