Two days after the event ends, ask a participant, "How was the event yesterday?" They will not recount the eight-hour rundown. Their answer typically consists of two pieces of memory: the most intense moment felt and how the event concluded.
Psychology refers to this pattern as the peak-end rule. For event organizers, this rule shifts the question from "how many engaging sessions do we have" to two sharper questions: where is the peak, and how does the event conclude.
Cold Water Experiment at 14 °C
In 1993, Daniel Kahneman and three colleagues asked 32 students to dip their hands into cold water, twice.
- Short trial: one hand, water at 14 °C, for 60 seconds.
- Long trial: the other hand, the same 60 seconds at 14 °C, then held for an additional 30 seconds while the water was gradually warmed, averaging from 14.1 °C to 15.2 °C. Still painful, just slightly less so.
They were then asked to choose one to repeat. 22 out of 32 people (69 percent) chose the long trial, even though it contained the exact same pain plus an extra half minute. In a repeat trial without pain measurement tools, 24 out of 37 people made the same choice.
Memory does not simply sum seconds. It weighs the pain at the worst point and the feeling at the last moment.
Not Just in the Laboratory
The same pattern is measurable in hospital action rooms. A randomized trial involving 682 colonoscopy patients (Redelmeier, Katz, and Kahneman, 2003) gave half of the patients a brief additional time at the end of the procedure, with a lighter sensation. The results were:
- the final moment rated as lighter: 1.7 versus 2.5 on a scale of 10;
- the entire procedure remembered as less unpleasant: 4.4 versus 4.9;
- patients in this group returned slightly more often for repeat colonoscopies (odds ratio 1.41, median follow-up 5.3 years).
The procedure was longer, the memories lighter. And it is those memories that determine whether people want to return.
How Strong, and Where the Limits Are
One experiment could be coincidental. A meta-analysis by Alaybek and colleagues (2022) combined 174 effect sizes, and the picture is more complete:
| Findings | Source | Implications for Events |
|---|---|---|
| The peak and end have a significant impact on overall evaluation (r = 0.581) | Alaybek et al., 2022 | Those two moments deserve to be designed, not left to chance |
| The average of the entire experience has a comparable impact | Alaybek et al., 2022 | An event that is flat from the start cannot be saved by one exciting moment |
| The impact of duration is nearly zero | Alaybek et al., 2022 | Adding hours does not enhance the impression |
| The opening moment is weaker than the peak and end | Alaybek et al., 2022 | Do not spend all surprises at the opening |
| A typical vacation lasts 7 days: this rule is not a prominent predictor | Kemp et al., 2008 | In multi-day events, ordinary days are also counted |
| Conferences: the order of presentations does not make a meaningful difference, the peak at the end of the conference has the strongest influence on loyalty | Godovykh and Hahm, 2020 | The order of speakers can follow technical needs, energy focused on the closing |
Translating It to the Rundown
Deliberately determine the peak. Write in the rundown what time the peak occurs and who is responsible for it. Every event has one most intense moment. If it is not designed, that moment will still occur, and it may not be enjoyable.
Remember that the peak can be negative. In the cold water experiment, the peak was the worst point. In an event, that point could be a dead microphone during the main session or a late food vendor. Backup plans are not just technical matters; they also help preserve participants' memories. The way to arrange this is discussed in the article on triggers and decision-makers in event contingency plans.
Design the ending as seriously as the opening. The above research did not measure parking lines or certificate distribution. But since memory weighs the last moment, it is worth asking: last according to whom? For the committee, the event ends when the MC closes. For participants, it may only feel complete when they exit the building.
Do not extend the event to make it feel more valuable. Duration is hardly counted. Additional exhausting sessions at the end could actually shift the conclusion to a worse point.
If you prefer to hear the explanation directly, there is a clip on why events need a wow effect.
Sources
- Kahneman, D., Fredrickson, B. L., Schreiber, C. A., and Redelmeier, D. A. (1993). When More Pain Is Preferred to Less: Adding a Better End. Psychological Science, 4(6), 401-405.
- Redelmeier, D. A., Katz, J., and Kahneman, D. (2003). Memories of colonoscopy: a randomized trial. Pain, 104(1-2), 187-194.
- Alaybek, B., Dalal, R. S., and colleagues (2022). All's well that ends (and peaks) well? A meta-analysis of the peak-end rule and duration neglect. Organizational Behavior and Human Decision Processes, 170, 104149.
- Kemp, S., Burt, C. D. B., and Furneaux, L. (2008). A test of the peak-end rule with extended autobiographical events. Memory & Cognition, 36, 132-138.
- Godovykh, M., and Hahm, J. J. (2020). Does the sequence of presentations matter for academic conferences? An application of the peak-end rule in event management. Journal of Convention & Event Tourism, 21(3), 201-224.