The Peak End Rule

A simple trick for the complex task of designing better experiences

Nobel Prize-winning psychologist and economist Daniel Kahneman and his colleagues have shown that what we remember from our experiences is most powerfully influenced by two things*:

1. How the experiences felt when they were at their emotional peak (best or worst)
2. How they felt when they ended.

There are logical evolutionary reasons for the peak end rule. Kahneman says: “Memory was not designed to measure ongoing happiness, or total suffering. For survival, you really don’t need to put a lot of weight on duration of experiences. It is how bad they are and whether they end well, that is really the information you need as an organism.*”

Kahneman has discovered that we have an experiencing self, and a narrating self.

The experiencing self is our moment to moment consciousness — our ability to be present. This is the fast, intuitive, unconscious mode of thinking and experiencing. The experiencing self remembers nothing. It tells no stories and is seldom consulted when it comes to making big decisions.

The narrating self weaves our experiences into a coherent story. The narrating self is essentially our curator and goes over our experiences with a thick eraser and red pencil. The narrating self takes the input from our experiencing self, edits it, and creates memory.

Our narrating self heavily sorts out what makes it into our memory.

Kahneman says each moment of the experiencing self lasts about 3 seconds, but most of these ‘units’ of experience vanishing under the relentless eraser our narrating self wields*. What gets remembered are changes in the story, significant (intense) moments in the story and how the experience ended — the length of the experience didn’t matter to your narrating self. He labeled this: duration neglect. From an evolutionary perspective, we don’t need to know how long a bear attacked us, we need to know: if it was a bad experience, and if it ended well — yes and yes! This is the information that will lead us to be best able to avoid another bear attack, and thus the information our brain are wired to store.

As experience designers we need to always keep the narrating self in mind. Don Norman goes so far to say that we should design for memory, not for actual experience.

Patient A (8 min procedure) rated the overall experience of pain at 7.5, while Patient B (24 min procedure), with the same pain peak, rated the experience at only 4.5!

The peak end rule is seductive in its simplicity. The human experience is far from simple. The human experience is complex and using the Peak End Rule should not be seen as a magic bullet, but rather glasses that can be put on, and taken off.

“Perception falls into the brain, as seeds into a furrowed field, or as sparks into a keg (Dewey, 1934) ”*

A few examples of Peak End Rule:

The Story Mapping Process, from Donna Lichaw

Use Story Mapping to design a climax (peak) into your experiences. This is one of the best tools I have found to consistently and powerful build a peak into an experience. I used in my own wedding, and can recommend this application!

• Design a cumulative celebration (Peak), that brings together all stakeholders, into change processes, training experiences, or events. This worked like a glue in the social movement 100 in 1 Day Cape Town, that my team of Kaospilots brought to Cape Town.
• The new Amazon Go stores have a pretty amazing Ending — you just walk out of the store after collecting your groceries. After people experience this simplicity, a long line at checkout will move from infuriating, to flat out intolerable.
• Me and my wife recently found out that simply by making sure that our dinner guest leave laughing, we always feel that it was a great night. Try it, it works!

What is exciting about the lens of the peak end rule, is that it is everywhere, just most of the time we are not conscious of how much our experience is shaped by the peak and ending.

Don’t believe Danny? See an eye opening cognitive bias codex here

As Kahneman’s below quote make abundantly clear, we tend to ignore our own ignorance. For humanity to move forward, we must not accept design solutions that do not critically take the human experience into account — our biases, and evolutionary mental wiring. We must acknowledge our own limitations, embracing the complexity of the task of ‘designing experiences’. Understanding how the narrating self and experiencing self create the peak end rule is a good first step.

Written by Kaospilot Experience Design
Since 1991, Kaospilot have worked systematically with the management of change and co-creation processes. We are a creative and experience design driven school that makes professional training programs in leadership, innovation, creativity and experience design. Our professional programs are not create simply to prepare leaders for the future, but to help them design it.