Memories of experiences are dominated by the most intense moment (peak) and the final moment (end), with duration largely ignored.
The remembering self evaluates experiences using two snapshots: the peak (most intense point, positive or negative) and the ending. A colonoscopy lasting 20 minutes with severe pain at the end is remembered as worse than one lasting 30 minutes with the same peak pain but a less painful ending—even though the longer procedure involved more total pain. This creates a systematic divergence between experienced utility (moment-to-moment happiness) and remembered utility (how we evaluate the experience afterward).
A vacation can be 'ruined' by a bad final day even if the previous week was wonderful. Conversely, ending a medical procedure with reduced pain (even if it extends duration) improves how patients remember it.
Longer pleasant experiences are always remembered as better—duration is largely ignored if the peak and ending are similar.
In the colonoscopy study, why did patients prefer the longer procedure with less pain at the end?
You're designing a customer service experience. How would you apply the peak-end rule to maximize customer satisfaction?
Logically equivalent choices produce different decisions when framed differently (as gains vs. losses, or with different reference points).
PrincipleContinuing an endeavor because of previously invested resources (time, money, effort) that cannot be recovered, even when continuing is irrational.
PrincipleFast, automatic, unconscious cognitive processing that operates through pattern recognition and associative memory without deliberate effort.
Mental ModelSlow, effortful, conscious cognitive processing required for complex calculations, unfamiliar tasks, and deliberate reasoning.
Mental ModelThe tendency to rely too heavily on the first piece of information encountered (the anchor) when making decisions, even when it's arbitrary or irrelevant.
PrincipleJudging the frequency or probability of events by how easily examples come to mind, leading to overestimation of vivid, recent, or emotional events.
PrincipleJudging probability by similarity to stereotypes or prototypes, while ignoring base rates and sample size.
PrincipleWhen faced with a difficult question, System 1 automatically substitutes an easier question without conscious awareness of the switch.
FrameworkLasting behavior change comes from shifting your identity (who you are) rather than focusing on outcomes (what you achieve).
from “Atomic Habits”
A specific plan that states when, where, and how you will execute a behavior: 'I will [behavior] at [time] in [location].'
from “Atomic Habits”
Pair an action you need to do with an action you want to do to make habits more attractive.
from “Atomic Habits”
Behavior change operates at three levels: outcomes (what you get), processes (what you do), and identity (what you believe).
from “Atomic Habits”
Identity changes through accumulated evidence: each habit execution is a vote for the type of person you want to become.
from “Atomic Habits”
Memories of experiences are dominated by the most intense moment (peak) and the final moment (end), with duration largely ignored.
A vacation can be 'ruined' by a bad final day even if the previous week was wonderful. Conversely, ending a medical procedure with reduced pain (even if it extends duration) improves how patients remember it.
Longer pleasant experiences are always remembered as better—duration is largely ignored if the peak and ending are similar.
Peak-End Rule is explored in depth in "Thinking, Fast and Slow" by Daniel Kahneman. Distilo provides a deep AI-powered analysis with key insights, audio narration, and practical frameworks.