# Peak-End Rule: Why Two Moments Define a Day

> The peak-end rule describes the pattern whereby people judge a past experience by its most intense moment and by how it ended, rather than by its length.

https://iamgrateful.life/en-GB/glossary/peak-end-rule


The peak-end rule is a claim about which moments survive. Judged afterwards, an experience tends to be scored by its most intense point and by how it finished — not by its average, and not by its length.

The evidence behind it starts with [duration neglect](/en-GB/glossary/duration-neglect). In [two 1993 experiments](https://pubmed.ncbi.nlm.nih.gov/8355141/), Fredrickson and Kahneman found that the length of an emotional episode barely affected how people evaluated it once it was over, and that their judgement resembled a weighted average of a few moments. Later work named the resulting pattern the peak-end rule. The 1993 paper demonstrated it, rather than naming it.

## What it means for a journal

The peak is usually not up for negotiation — the message arrived, the meeting went how it went. The ending sometimes is. The last few minutes before sleep are unusual in that almost nothing happens in them except whatever you turn your attention to, which is why [writing three specific good things](/en-GB/blog/peak-end-rule-journaling) at that hour is a low-cost thing to try. No study has tested whether it changes how the day is remembered.


## Research

- [Duration neglect in retrospective evaluations of affective episodes](https://pubmed.ncbi.nlm.nih.gov/8355141/) — Fredrickson, B. L., & Kahneman, D. (1993)

## Common questions

### What is the peak-end rule?

It is the pattern whereby a past experience is judged by its most intense moment and by how it ended, rather than by its average or its length. It grew out of duration neglect, which Fredrickson and Kahneman demonstrated in two 1993 experiments; the peak-end name came from later work rather than from that paper.

### Does journalling at night change how I remember the day?

No study has tested that directly, so treat it as a reasonable possibility rather than a finding. What the research supports is narrower — the closing moments of an experience carry disproportionate weight in how it is remembered. Writing three specific lines puts something concrete in that slot instead of leaving it to whatever you were scrolling through.

### Does this mean I can talk myself into a good day?

No, and it is worth being clear about that. Nothing in the peak-end rule says a bad day was secretly fine. The unpleasant moment still happened, and three lines do not undo it. What changes is which moments are still available when you try to recall that day later.

## Keep reading

- [The peak-end rule: two moments become the whole day](https://iamgrateful.life/en-GB/blog/peak-end-rule-journaling)
- [Duration neglect](https://iamgrateful.life/en-GB/glossary/duration-neglect)
- [Fading affect bias](https://iamgrateful.life/en-GB/glossary/fading-affect-bias)
- [Negativity bias](https://iamgrateful.life/en-GB/glossary/negativity-bias)
- [Savouring](https://iamgrateful.life/en-GB/glossary/savoring)