Cognitive bias; memory heuristic; behavioral decision theory

Peak End Law

Make the most intense moment better, reduce the worst moment, and end well. People may forget many details, but the peak and the ending often become the story they remember.

Popularity

Usefulness

Aliases

Peak-End Law / Peak-and-End Rule / Peak-End Effect / related to Duration Neglect and Remembered Utility

Domains

Psychology / behavioral economics / user experience / service design / healthcare experience / customer experience

Definition

The Peak–End Rule is the tendency for people to evaluate a past experience mainly by how they felt at its most intense moment and at its ending, rather than by the total duration or average quality of the whole experience. (Wikipedia)

Core Idea

People do not remember an experience as a perfect timeline. Instead, memory often compresses the experience into a few important “snapshots,” especially the emotional peak and the final moment. (Warrington College of Business)

How It Works

During an experience, people may feel many changing levels of pleasure or discomfort.
Later, when judging the experience, they often give extra weight to:
- the peak: the most emotionally intense point, positive or negative;
- the end: how the experience concluded.
Duration may be underweighted, especially when people are not explicitly comparing how long different experiences lasted. (Warrington College of Business)

Usage Example

A customer waits a long time at a restaurant, but the staff handles the mistake politely, gives a sincere apology, and ends the meal with a thoughtful dessert. The customer may remember the visit more positively because the ending improved the overall memory.

Famous Example

Example: In a 1993 cold-water experiment, participants experienced two uncomfortable trials: one shorter cold-water trial and one longer trial that added extra time but ended slightly less painfully. Many participants preferred to repeat the longer trial, even though it involved more total discomfort, because the ending was less unpleasant. (JSTOR)
Why it fits this rule: The participants’ later choice appeared to be influenced more by the peak and the end of the discomfort than by total duration.
Verification status: Verified as a published research example, commonly cited in the Peak–End Rule literature.

Use Cases / Situations Where It Applies

Designing customer service experiences.
Improving onboarding or checkout flows.
Planning lessons, workshops, or events.
Designing medical or dental patient experiences.
Reviewing entertainment, travel, dining, or hospitality experiences.
Improving product experience by reducing painful peaks and ending with clarity or reassurance.

When Not to Use or Common Misuse

Do not assume duration never matters; later research suggests duration can matter when it is made salient or easy to compare. (ScienceDirect)
Do not use it as an excuse to ignore the whole experience; a terrible middle can still create a negative peak.
Do not treat it as a universal law that predicts every memory or every decision.
Do not say Kahneman won the Nobel Prize for the Peak–End Rule specifically. He received the 2002 Nobel Memorial Prize in Economic Sciences for integrating psychological research into economics, especially judgment and decision-making under uncertainty. (NobelPrize.org)

Rule Invention / Origin

Invented by: Not a single “invention” in the strict sense. The rule is most strongly associated with Daniel Kahneman and Barbara L. Fredrickson’s work on remembered utility and duration neglect, with important related studies involving Charles A. Schreiber and Donald A. Redelmeier. (Warrington College of Business)
Year of invention: 1993 is the key publication year for foundational studies on duration neglect and the peak/end pattern. (Warrington College of Business)
Country / context of origin: Academic psychology and behavioral decision research, mainly in North American research contexts.

Evidence / Research Basis

Fredrickson and Kahneman’s 1993 research on retrospective evaluations showed that people’s later evaluations of affective episodes were not simply based on total duration. (Warrington College of Business)
Kahneman, Fredrickson, Schreiber, and Redelmeier’s 1993 cold-water study provided a classic demonstration that people may prefer a longer unpleasant experience if it ends less badly. (JSTOR)
Redelmeier and Kahneman’s 1996 study examined real-time and remembered pain in medical procedures such as colonoscopy and lithotripsy. (PubMed)
A 2022 meta-analysis reported that the peak-end effect is generally robust, while also comparing it with other predictors such as duration, beginning, trough, trend, and average experience. (ScienceDirect)

Short Practical Takeaway

Make the most intense moment better, reduce the worst moment, and end well. People may forget many details, but the peak and the ending often become the story they remember.