Peak–End Rule, explained.
The peak–end rule describes how evaluations of an experience can give disproportionate weight to its most intense moment and its ending, rather than its full duration.
Why it happens
Remembered evaluation and the sum of moment-to-moment experience are different summaries. A simplified peak-and-ending score can rank experiences differently from an average. That formula illustrates a possible weighting pattern, not a complete model of human memory.
A simple peak–end summary can differ from the average of every moment.
Read the result
Compare the average experience with the peak–end score as the ending changes. Notice when the rankings diverge, while keeping the rest of the sequence in view.
A worked example
An uneven day out
One outing is pleasant throughout but ends badly. Another has mixed moments and finishes especially well.
You compare the entire sequence with a summary emphasizing the strongest moment and the ending.
The remembered favorite may differ from the option with the better overall average. Both perspectives contain information.
OPTIONAL DEEPER DETAILGo deeper: inside the model
Inside this model
Experience A has scores [6,6,6,6,ending]; B has [4,7,7,7,6]. The plot compares cumulative average and a peak–end score equal to the mean of maximum and final score.
Where this idea is useful
A practical use
When evaluating an event, compare the full record with the moments that stand out in memory.
A common misconception
“Only the peak and ending matter to people.”
Duration, context, expectations, and other moments can matter too. The rule describes a tendency, not a universal memory algorithm.
What this explanation leaves out
- Human memory is not literally a two-number formula, and negative experiences can behave differently.
Should a good ending excuse a bad experience?
No. A favorable memory is not a substitute for good conditions throughout. Compare remembered satisfaction with the actual sequence of experiences.
Are you improving the whole experience or only its most memorable moments?
Associated thinkers
Further reading
Explore the original research or the teaching reference behind this experiment.