Experiences are judged by their peak and their end.
Daniel Kahneman’s research shows people judge an experience by its most intense moment and its final one — not its average. Design the peak, stick the landing, and fix the worst moment first.
Daniel Kahneman, the Nobel-winning psychologist, established the rule with Barbara Fredrickson in the early 1990s — most famously in a 1993 cold-water study where a longer trial with a slightly warmer ending was preferred over a shorter, objectively better one.
The work separated the experiencing self from the remembering self: what we choose to repeat is decided by the memory, not the experience. Colonoscopy studies with Donald Redelmeier confirmed it clinically — endings changed how whole procedures were remembered.
People judge an experience largely by how it felt at its peak — the most intense point, good or bad — and at its end, rather than by the sum or average of every moment. Duration barely registers; the remembered shape is what returns.
Plot an experience over time and memory keeps only two points: the extreme and the final. Everything else — including how long it took — collapses. Two moments decide the review, the renewal, and the recommendation.
Every flow deserves a deliberate peak: the confetti on a first publish, the instant preview, the moment the import just works. One engineered high point outweighs a dozen small conveniences in memory.
The last screen of a flow is disproportionately remembered. A clear confirmation, a summary of what happened, and an obvious next step turn an ordinary transaction into a good memory of your product.
Cancellations, returns, and account deletions are endings too — often the final memory a user takes away. A graceful exit converts a churned user into a possible return; a hostile one writes the lasting review.
A negative peak dominates memory the same way a positive one does. Before polishing anything, find the single worst moment in the journey — the crash, the lost form, the surprise charge — and remove it.
A short flow with a flat finish is remembered worse than a longer one that ends well. Adding a satisfying final beat can beat shaving seconds — memory doesn’t bill by the minute.
A conversation with a model is an experience with a peak and an end. The last answer — and the worst one — is what the user carries away.
Users judge a whole session by the final response. A conversation that ends on a correction, a refusal, or a half-answer is remembered as a failure — close with the resolved answer and a clean next step.
When the model gets something wrong, the correction moment becomes the emotional peak of the session. A fast, gracious recovery is remembered better than a session that was merely fine throughout.