Our natural assumption is that the final ratings would represent something like the sum of the moment-by-moment ones. We believe that having a longer duration of pain is worse than a shorter duration and that having a greater average level of pain is worse than having a lower average level. But this wasn’t what the patients reported at all. Their final ratings largely ignored the duration of pain. Instead, the ratings were best predicted by what Kahneman termed the “Peak-End rule”: an average of the pain experienced at just two moments—the single worst moment of the procedure and the very end. The gastroenterologists conducting the procedures rated the level of pain they had inflicted very similarly to their patients, according to the level of pain at the moment of greatest intensity and the level at the end, not according to the total amount.
People seemed to have two different selves—an experiencing self who endures every moment equally and a remembering self who gives almost all the weight of judgment afterward to two single points in time, the worst moment and the last one. The remembering self seems to stick to the Peak-End rule even when the ending is an anomaly. Just a few minutes without pain at the end of their medical procedure dramatically reduced patients’ overall pain ratings even after they’d experienced more than half an hour of high level of pain. “That wasn’t so terrible,” they’d reported afterward. A bad ending skewed the pain scores upward just as dramatically.
Studies in numerous settings have confirmed the Peak-End rule and our neglect of duration of suffering. Research has also shown that the phenomenon applies just as readily to the way people rate pleasurable experiences. Everyone knows the experience of watching sports when a team, having performed beautifully for nearly the entire game, blows it in the end. We feel that the ending ruins the whole experience. Yet there’s a contradiction at the root of that judgment. The experiencing self had whole hours of pleasure and just a moment of displeasure, but the remembering self sees no pleasure at all.
If the remembering self and the experiencing self can come to radically different opinions about the same experience, then the difficult question is which one to listen to. This was Jewel Douglass’s torment at bottom, and to a certain extent mine, if I was to help guide her. Should we listen to the remembering—or, in this case, anticipating—self that focuses on the worst things she might endure? Or should we listen to the experiencing self, which would likely have a lower average amount of suffering in the time to come if she underwent surgery rather than if she just went home—and might even get to eat for a while again?
In the end, people don’t view their life as merely the average of all of its moments—which, after all, is mostly nothing much plus some sleep. For human beings, life is meaningful because it is a story. A story has a sense of a whole, and its arc is determined by the significant moments, the ones where something happens. Measurements of people’s minute-by-minute levels of pleasure and pain miss this fundamental aspect of human existence. A seemingly happy life may be empty. A seemingly difficult life may be devoted to a great cause. We have purposes larger than ourselves. Unlike your experiencing self—which is absorbed in the moment—your remembering self is attempting to recognize not only the peaks of joy and valleys of misery but also how the story works out as a whole. That is profoundly affected by how things ultimately turn out. Why would a football fan let a few flubbed minutes at the end of the game ruin three hours of bliss? Because a football game is a story. And in stories, endings matter.
Yet we also recognize that the experiencing self should not be ignored. The peak and the ending are not the only things that count. In favoring the moment of intense joy over steady happiness, the remembering self is hardly always wise.
“An inconsistency is built into the design of our minds,” Kahneman observes. “We have strong preferences about the duration of our experiences of pain and pleasure. We want pain to be brief and pleasure to last. But our memory … has evolved to represent the most intense moment of an episode of pain or pleasure (the peak) and the feelings when the episode was at its end. A memory that neglects duration will not serve our preference for long pleasure and short pains.”