The peak-end rule affects how an individual remembers an event by simplifying the memory and emphasizing its peaks and ending.³ The peak-end rule can be problematic as human events and memories are complex in nature. More specifically, future decisions are largely based on biased memories, not actual experiences. By simplifying a memory, individuals may misinterpret past events and risk making wrong assumptions and poor decisions.

Let’s look at this in more detail. The peak-end rule shapes our memory of what’s known as ‘experienced utility’ (another of Daniel Kahnemann’s concepts), or the actual moment-to-moment pleasure or discomfort felt during an experience. This means that when people recall past events, they don’t remember the full duration of pleasure or pain but instead focus on the most intense moment (peak) and how the experience ended. This distortion means that people often make future decisions based on selective, emotionally charged memories rather than their true, overall experience.

An example of how the peak-end rule can alter our memories and thus our decision-making is our negative experiences at the dentist. A trip to the dentist can be an unpleasant experience for many, but it’s essential that we regularly maintain and check up on our dental health. If we experience an adverse event at the dentist and remember our visit as primarily negative, this could deter us from checking up on our dental health later on. Therefore, our warped interpretation of our experience at the dentist can significantly impact our choices, bearing consequences to our health.

In contrast, the peak-end rule may explain why some people feel like they continually make ‘terrible life choices.’ That is, individuals may repeat bad experiences simply because they had a strong peak or positive ending, which distorted their memories. For example, a person might return to a toxic relationship because on the day of the breakup, their partner gave them lavish gifts in an attempt to convince them to stay.

The peak-end rule is also commonly used by companies to design better experiences for their customers and generate more sales. By strategically shaping customer experiences—emphasizing peak moments and ensuring positive conclusions—brands can enhance customer recall and leave a lasting, favorable impression of their product. Examples of peak-demand and marketing techniques include surprise discounts at checkout or providing small departure gifts as customers exit an establishment. By making the last impression a good one, customers are more likely to return and think highly of a product or brand.⁴

The peak-end rule can also impact our experiences in the workplace and our overall job satisfaction. The effects of this bias can be seen before we’ve even signed a contract. Candidates for a job evaluate and form their impressions of a company based on the experiences they have during the hiring process.²⁸ The peak-end rule can significantly shape our memory of this experience. For instance, if the interview reaches its peak with an engaging conversation about career growth opportunities, followed by a friendly farewell, the candidate is likely to recall the interview positively. Conversely, if the candidate experiences an uncomfortable moment, like confusion over unclear instructions or a lukewarm farewell, it can result in a persistently negative memory.

When we come to the end of our time in a job, the peak-end rule comes into play again. Employees often evaluate their job based on its most intense challenges and how it concluded, rather than considering the entire experience objectively. This means that even if an employee had a generally positive experience, their overall perception can be significantly influenced by particularly difficult moments or a stressful ending. For instance, an employee who enjoyed years of fulfilling work may still leave with a negative impression if their final months were marked by high stress, poor management, or unresolved conflicts. Arguably, in this context, the peak-end rule affects both the individual and the system—the employee leaves with a bad taste in their mouth, and the employer may get an unwarranted bad reputation.

The peak-end rule is a cognitive bias that develops in individuals for a multitude of reasons.

Representativeness heuristic - Why we only remember snapshots

Based on work by Dr. Daniel Kahneman and Dr. Barbara Fredrickson, the peak-end rule happens as a result of the representativeness heuristic, which is a mental shortcut used to help individuals make quick decisions by prototyping people or moments.⁵ The representativeness heuristic explains why an event is not judged or remembered by the entirety of its experience, but rather by snapshots of the memory, which trigger an emotional response in individuals.⁶ The retained value of those snapshots then dominates the value of an individual’s experience. Additionally, the peak-end rule is only applicable if a moment or experience has definite beginning and end periods.

Memory bias – Why the peak is memorable

Individuals demonstrate better memory for events that are more emotionally intense. Though the cause for this is unclear, it has been widely proven in various studies, experiments, and surveys.^7,8,9 Additionally, individuals don’t always recognize that the events they remember are more emotionally intense. Instead, they may believe they are recalling experiences objectively, unaware that their memories are shaped by emotional peaks rather than a full, balanced recollection of the event. This can lead to a distorted perception of past experiences, where less intense but equally significant moments are forgotten, while the most emotionally charged moments take centre stage.

Recency bias – Why the end is memorable

Individuals typically remember both the beginning and end of a memory better due to serial position effects, such as primacy bias and recency bias. Recency bias is a cognitive bias that causes individuals to remember something that has happened recently more easily. The peak-end rule is influenced by this bias, which is why we remember both the peak emotional moments and the end.¹⁰

An individual’s representativeness heuristic bias and their tendency to remember emotionally intense moments lead to what is known as the peak-end rule.

The peak-end rule can warp an individual’s perception of past events and memories. By being aware of the cognitive bias, individuals can avoid it or use the peak-end rule to their benefit.

The cognitive bias can be used to our advantage when an individual is aware of it.² By leveraging the bias, individuals can craft how their memories are formed, creating more positive memories.

Ending on a High Note

By ending experiences on a high note, it’s typical that they will be remembered in a more positive light. Actively focusing on positively ending experiences can be done in several ways. For example, if you have a lousy dinner, you can finish your night by getting ice cream from your favorite restaurant. Finding something positive to focus on can help create positive memories from unpleasant experiences.¹¹

Gradual Relief

Additionally, when going through something uncomfortable or painful, it has been proven that gradual relief, rather than immediate comfort, provides individuals with more positive memories from the experience. Researchers have found that this technique can be used in an array of real-life cases, specifically with an individual’s health. For people who tend to shy away from exercise, ending a high-intensity workout at a lower intensity has been shown to make them feel positive about the experience and more likely to continue  (not to mention, it’s important for avoiding injury!).¹² Ending uncomfortable and challenging exercises on a gradual, positive note makes individuals more likely to keep exercising, helping them work toward their health.

By being aware of the peak-end rule and using it to our advantage, we can significantly improve our well-being and happiness by viewing more and more of our memories as positive experiences.²

Depending on the situation, an individual may or may not want to avoid the peak-end rule. For example, when creating memorable customer experiences, businesses might intentionally leverage the peak-end rule to emphasize standout moments and positive conclusions. Conversely, in situations where accuracy or objectivity in evaluation is critical, such as performance appraisals or medical assessments, it may be beneficial to minimize reliance on peak-end biases to ensure fair and comprehensive judgments.

Yet if clarity of mind and memory is what you’re aiming for, here are some useful tips: 

Avoiding Focusing on Negative Elements

Dwelling on and remembering negative peaks of a situation or memory enables the peak-end rule to shape our perception of a past event. Consider an individual’s experience of eating at a restaurant. The food was excellent, but the service was poor. By making a conscious effort to focus on the right parts of the meal (the positive peaks), such as the quality of the food, an individual can avoid being consumed by an event’s negative elements.

Reframe the Moment

Memories and past events can be reframed to create more positive and intense emotions in our recollection of them. By focusing on positive elements of memory or reframing the timeline of a moment, we can change our perception of the memory and avoid the peak-end rule. This approach is often used in therapeutic situations, particularly when it comes to revisiting painful childhood memories.

Less is More 

Researchers from Dartmouth College in New Hampshire tested the peak-end rule in evaluating pleasurable experiences.²¹ In one experiment, Dartmouth College students who donated to charity were entered into a raffle to win DVDs. Some received only one highly rated DVD (peak pleasure), while others received the same DVD plus a second, less desirable one. Surprisingly, those who received only the highly rated DVD reported greater overall satisfaction than those who received two, demonstrating that adding a mildly positive experience at the end diminished overall pleasure. A second experiment on Halloween trick-or-treaters showed similar results—kids preferred receiving just a full-size chocolate bar over getting the chocolate bar plus a piece of bubble gum. These findings confirm that people don’t assess total pleasure objectively but instead rely on peak moments. A valuable lesson for parents whose children just keep wanting more. 

The peak-end rule evolved from earlier cognitive psychology theories, particularly the Snapshot Model, which suggested that people remember experiences as a series of key moments rather than a continuous sequence. Early research in memory and decision-making, especially by Daniel Kahneman and Amos Tversky in the 1970s and 1980s, demonstrated that individuals rely on heuristics to recall and evaluate past events.²⁶ Other developments in the field of psychology also paved the way for the eventual development of the peak-end rule. In 1972, Endel Tulving, an Estonian-Canadian psychologist, introduced the concept of episodic memory.²⁷ This theory explains how individuals recall past events as distinct, fragmented episodes rather than as a continuous stream of information.

The peak-end rule was first brought to light by Israeli psychologist and economist Daniel Kahneman and researcher Barbara Frederickson. Through their notable 1993 study titled “When More Pain is Preferred to Less: Adding a Better End,” the researchers found that the human memory seldom records series of events with accuracy, thus giving evidence to the influence of the peak-end rule in our memory processes.¹³

The research study asked participants to endure an uncomfortable (but not dangerous) experimental condition during which they were subjected to two versions of the same unpleasant experience. The experiment’s first trial asked participants to submerge one hand in 14°C water for 60 seconds. The second version of the trial asked study participants to submerge their other hand in 14°C water for 60 seconds. Additionally, participants were asked to keep their hand submerged for 30 seconds while the temperature of the water was raised by 15°C. After these two trials, participants were asked which option of the trial they would choose to repeat. Study subjects were found more willing to repeat the second trial, despite the prolonged exposure to uncomfortable temperatures. The study concluded that this happened because “subjects chose the long trial simply because they liked the memory of it better than the alternative, or disliked it less.”¹³ This phenomenon has also been applied in medical situations, where patients prefer slightly prolonged procedures if they end on a more positive experience (read more in the case study below).

So while the snapshot model initially proposed that selective, intense moments shape our memory, the peak-end rule refined this by specifying which moments (peaks and endings) matter most.

Peak-end rule is an important concept for designers to keep in mind when developing products and enhancing user experience (UX). In order for a user to look back on their interaction with a product or service positively, it’s vital to pay close attention to the most intense points, and the final moments, of the user’s journey.¹⁸ Language learning apps such as Duolingo use positive affirmations and celebratory images when a user has completed a new module or test. While the actual content may have been hard or frustrating, the positive ending instills a sense of accomplishment in the user, which is carried forward as they continue to use the app.

The peak-end rule is leveraged by businesses to shape, and sometimes manipulate, our experiences with their services and products. If you’ve ever visited one of the 12 Disney Amusement Parks around the world, you’ll be familiar with the digital boards that display the current estimated wait time at the beginning of each ride queue. We like to trust that these are correct, but in reality, they are slightly inflated; if the real wait time is 45 minutes, the board will tell us 50 minutes. So we enter the queue a little annoyed that we’re wasting 50 minutes of our precious time standing around, but when we finally get to the front of the queue, we’re pleasantly surprised to find that the wait time was 5 minutes less than expected. Disney, therefore, is trading off a slightly higher level of irritation at the beginning of the queue with ending on a positive note - that is, a good ending to an overall negative wait.²⁰ When we look back on our day at the theme park, we’re more likely to remember how happy we were that the queues ‘weren’t that bad.’ 

The way in which we perceive and engage with advertisements is also influenced by the peak-end rule. In a series of studies by Baumgartner et al., the authors explored how people form overall opinions about advertisements based on their moment-to-moment emotional reactions.²³ In the first study, they found that consumers’ overall impressions of an ad are mainly shaped by the most emotionally intense moment (the peak) and how the ad ends. Another study suggests that people prefer ads that build up to an emotional high point and finish strongly. The researchers also concluded that longer ads can either improve or hurt overall impressions, depending on how they influence the peak moment and ending. In general, the ads that make people feel strong emotions are usually the most effective.²⁴ 

Overall, the peak-end rule can be used by businesses and brands to increase customer satisfaction and loyalty, enhance user experience, and drive higher sales. 

Artificial Intelligence (AI) can enhance the way we leverage the peak-end rule across a range of contexts. This is particularly the case in areas where AI interacts with human experiences, such as customer service, healthcare, entertainment, and user experience (UX) design.

If you’ve ever used an AI-driven chatbot or virtual assistant on a website or an app, you’ll likely have noticed how polite the bot is when your conversation comes to an end. It may leave you with a personalized, warm response such as “I’m glad I could help! Is there anything else I can do for you?” Even if the interaction has minor frustrations or took longer than you expected, the user will likely be left with a better memory of the experience as a result of this pleasant ending.

AI can also quickly and effectively analyze user behavior to optimize peak moments and endings in digital experiences. In e-commerce, for example, AI optimizes checkout processes and post-purchase engagement, such as Amazon’s seamless one-click checkout or personalized thank-you messages from chatbots.

As our lives continue to be dominated by the digital world, AI will become increasingly important for advancing the application of the peak-end rule. While humans can intuitively design experiences with emotional peaks and strong endings, they cannot analyze vast amounts of data, personalize experiences in real-time, and automate engagement at scale. AI, therefore, enhances the precision, consistency, and adaptability of our application of the peak-end rule and other cognitive biases in a way that manual efforts cannot match. However, over-reliance on AI could unintentionally reinforce or amplify existing cognitive biases, potentially leading to systematic inaccuracies or ethical concerns.

An example of the peak-end rule applies to students and their educational experiences, particularly regarding student-teacher peer assessment. A study conducted by Vincent Hoogerheide, a psychology professor, focused on education and child studies. He analyzed the effects of the peak-end rule in a children’s experiment of giving and receiving peer assessments.¹⁴

The study consisted of two different experiments, one giving a positive assessment and the other offering a negative evaluation to students. In each experiment, the students received two versions of the assessments with two different lengths. The overall negative assessment showed that the extended version had a moderately negative rating at the end. In parallel, the positive rating also ended with a moderate positive rating. In both experimental conditions, students remembered the extended assessment as more pleasant and less difficult to process and deal with.

Based on these results, Hoogerheide and his research team advised teachers to structure their feedback by ending with the most positive part of the assessment. Even when the evaluation is overall negative, his team notes that it’s better to end with the most pleasant or acceptable section of the feedback. Similarly, the positive assessment should also end with the most positive feedback. The study demonstrated that the peak-end rule likely influences children’s memory of the evaluation and impacts their motivation and learning outcomes if appropriately received.

The peak-end rule has been extensively studied in medical procedures, with evidence suggesting that patients prefer to have more lengthy medical procedures that include a period of decreased discomfort rather than more uncomfortable, shorter procedures.16 In other words, the peak-end rule states that painful medical treatment is likely to be less aversive if relief from the pain is gradual than if relief is abrupt.¹³

A typical example of the peak-end rule and its effects on medical procedures is the famous patient retrospective pain evaluations of uncomfortable colonoscopy procedures. Kahneman and Redelmeier conducted a study in 1996 to assess patients’ appraisals of these uncomfortable procedures to test responses based on their use of the peak-end rule. The study found that colonoscopy patients consistently evaluated the discomfort of the procedures based on the intensity of the pain at the worst and the final moments of the procedure, regardless of the length or the pain intensity experienced.¹⁶

Another study conducted by Kahneman and Redelmeier further expanded on the discoveries made in their initial 1996 study. The study took colonoscopy patients and randomly divided them into two groups. One group of patients underwent a colonoscopy procedure during which the scope was left in for three extra minutes but not moved. This caused discomfort but not pain for the patients. The other group of participants underwent typical colonoscopy procedures without additional time added. When participants were asked to recall and evaluate their experiences from the experiment, the researchers found that patients who had prolonged colonoscopy procedures rated their experience as less painful than those who underwent the typical procedure. Additionally, patients who felt prolonged discomfort were far more likely to return for subsequent procedures. The gradual release of discomfort from these more prolonged procedures led to patients evaluating the experience as more positive than the other set of patients.¹⁷

What it is

The peak-end rule is a cognitive bias that changes the way individuals recall past events and memories. According to the peak-end rule, individuals judge a past experience based on the emotional peaks felt throughout the experience and the end of the experience. The peak-end rule applies to both positive and negative memories.

Why it happens

The peak-end rule occurs due to representativeness heuristic bias, memory bias, and recency bias. The representativeness heuristic bias causes an individual to remember an experience in snapshots of a memory, rather than its entirety. Memory bias refers to an individual’s ability to better recall a memory due to the emotional intensity experienced during the event. Recency bias refers to an individual’s ability to remember the end of an event better, as it’s the most recent thing that happened.

Example 1 – Ending with positive statements creates better learning assessments

The peak-end rule is common in education settings and student feedback assessments. Students remember and react better to feedback if their assessment ends with a positive statement. This then translates into greater motivation to achieve better learning outcomes from the evaluation.

Example 2 – Medical patients would rather endure longer uncomfortable procedures than shorter painful procedures

The peak-end rule is also commonly applied to medical procedures and has been studied extensively in healthcare contexts. Studies assessing patients and uncomfortable procedures, such as colonoscopy procedures, noted that participants preferred having longer procedures that include a period of decreased discomfort rather than shorter, more uncomfortable procedures.

How to avoid it

After developing an awareness of the peak-end rule, it can be further avoided by reframing memories and focusing on positive moments instead of negative ones from an event.

Modern CX is Behavioral: How the Peak-End Rule Can Revolutionize Customer Experience

CX, or customer experience, is all about memories. Either good or bad, they can ultimately determine whether we engage with a brand or product in the future. This article delves into the peak-end rule approach to CX decisions and how this cognitive bias can revolutionize the way in which brands and businesses keep us going back for more. 

Why do we better remember items at the end of a list? 

As we’ve seen from the peak-end rule, humans are quite selective about what they do and don’t remember. The recency effect refers to our tendency to better remember and recall information presented to us most recently, compared to information we encountered earlier. This cognitive bias can influence everything from remembering grocery lists to the winner of the Eurovision Song Contest, and plays an important role in skewing our decision-making.