Home > Cognitive Bias, Memory > Why A Single Incident Can “Make Your Day” – The Peak-End Rule

Why A Single Incident Can “Make Your Day” – The Peak-End Rule

You Just Made My Day!

Following an exceptionally pleasant incident, people often use the expression “That just made my day!”. Of course, one single joyful moment cannot really change the nature of a day, but we use that expression because that moment does make us feel better, and will likely resonate with us until the end of day. Similar experience also applies to incidents that upsets us. For example, when we go to a restaurant, if a full bowl of hot soup gets flipped accidentally and spilled all over us at the end of that meal, even if the food and the service are good, it is likely that we would consider restaurant a terrible place and would never visit there again. The way we judge a situation or experience depends highly on moments that are associated with the most intense feelings, as well as what we get from the situation at the end. In psychology, such effect is called the Peak-End Rule, according to which the two points of peak (i.e. intense experience) and end (i.e. conclusion we have), instead of the sum or the average of our experience, serve as indicators which people use to judge their experience.

The Peak-End Rule Graph

The Peak-End Rule was coined by Kahneman and colleagues (1993), who proposed this phenomenon after their classic pain perception experiment, in which participants were exposed to ice water for either 30 seconds or 90 second. In last 30 seconds of the 90 second condition, participants were exposed to water that was one degree warmer (but still very cold). Surprisingly, participants exposed to ice water for longer time rated their experience as less painful, because they receive a “warmer” stimulus at the end. In other words, participants didn’t rate their experience based on how much they were exposed to the unpleasant stimuli, but how the experience ended (Do, Rupert, & Wolford, 2008). More information about this phenomenon can be found here.

In our daily life, a very good example that can be used to illustrate the Peak-End Rule is mountain hiking. During the hiking, climbers usually focus on how being at the peak of the mountain feels and the sense of achievement they obtain afterwards. No matter what happens on their way to the top or to the bottom, such as all the difficulties and setbacks or the time they take to rejuvenate, as long as they reach the top, all unhappiness would disappear because climbers evaluate their experience based on the epitome point of the experience where massive intensity take place.

For myself, the best personal experience to explain the Peak-end Rule is rating movies. In the case of movie, I often value the climax, which is the most intense part of the movie, and the ending as most important parts of the movie. I tend to increase my overall ratings of the movie according to the dominant feeling that is present at the climax and the end. If a movie is generally good but does not have a brilliant climax, such as a strong realization or a death of major characters, I will not give a high rating for it. On the other hand, even if a movie has great climax and storyline, but end on a bad note or leave the storyline unfinished, I will not give a high rating too. This is a clear indication of how I base my evaluation for movies on the quality of the climax and the end of my watching experience.

So, what’s the logic behind the Peak-end Rule? There are two hypothesized explanations for the effect. The first one is that people tend to have better memory with event that are more emotion-embedded, and this explains why people value peak experiences, given that events associated with more intense feelings would leave a more memorable mark in people’s mind, and thus influence people’s experience (Morewedge, 2013). The second explanation is the recency effect, which suggest that when people are better at recalling events that happened recently. It indicates that the more recently received information would be remembered better than earlier received information and would have greater impact in forming a judgement. This can explain why people value the end of event so much (Garbinsky et al., 2014).

Bungee jumping is considered as one of the most exciting things to do during vacation

Moreover, why should we care about the Peak-End Rule? Think about your day-to-day life, and you will find that this effect relates to every aspect of it. Try to remember your last meal you had, your last conversation you had, your last traveling experience, etc. How would you evaluate those experience? What do you remember? Those small events together build our life, and the way we experience those events determines how we feel about our lives. After learning the Peak-End rule, we now know that moments that bring the most intense experience and the ending of events are the most impactful to our judgements. Knowing this rule allow us to tweak our experiences. For example, in the previous study which asked participants to rate their vacation, results showed that overall happiness of vacation is not associated with length of the vacation, but instead relate strongly to the most memorable period, as well as the end of the vacation (Kemp, Burt, & Furneaux, 2008). So next time when we go on a vacation, we can make the experience better by saving the best activity for the last day. For example, bungee jumping can be a perfect way to end your vacation if you love excitement!

Another take-away message is that we should be cautious about how the Peak-End Rule may make it difficult for us to appreciate small pleasures, given that one major incident can entirely change how we experience a situation. Being aware of this tendency of overemphasizing significant events can help us noticing times when we catastrophize minor discomforts and let them ruin our pleasant feelings. By being more mindful to the present, it is possible for us to live more “in the moment” and start to appreciate pleasurable experiences that are neither peak or end.


Do, A., Rupert, A., & Wolford, G. (2008). The peak-end rule . Psychonomic Bulletin & Review, 15(1) , 96-98.

Garbinsky, E. N., Morewedge, C. K., & Shiv, B. (2014). Interference of the end: Why recency bias in memory determines when a food is consumed again. Psychological Science, 25(7), 1466-1474.

Kahneman, D., Fredrickson, B. L., Schreiber, C. A., & Redelmeier, D. A. (1993). When more pain is preferred to less: Adding a better end. Psychological science, 4(6), 401-405.

Kemp, S., Burt, C., & Furneaux, L. (2008). A test of peak-end rule with extended autobiographical events. Memory and Cognition, 36(1) , 132-138.

Morewedge, C. K. (2013). It was a most unusual time: How memory bias engenders nostalgic preferences. Journal of Behavioral Decision Making, 26(4), 319-326.

Whitbourne, S. (2012, September 8). Happiness: Its All About The Ending. https://www. psychologytoday.com/us/blog/fulfilment-any-age/201209/happiness-it-s-all-about-the-ending

You Made My Day Picture: https://www.flickr.com/photos/itsabitblurry/6523458523

The Peak-end Rule Picture: https://alyjuma.com/peak-end-rule/

Bungee Picture: https://medium.com/checkinstory-blog/7-reasons-to-go-bunjee-jumping-now-55efe1e65687











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