I’m sure you’ve heard how unreliable your memory is. Our memories change over time and are subject to a variety of influences and biases. Those of you who became addicted to the podcast Serial are very familiar with the inadequacies of memory. But what if you could have some control over your memories? What if you could make it more likely you’d remember certain events, even unpleasant or painful ones, in a positive light? You can!
According to the Peak-End Rule, we tend to judge an experience by its highs and lows (peaks) or the last part (end). Image credit: Alex Medick via Flickr.
All’s well that ends well
It turns out our memories are subject to something called the Peak-End rule. We don’t remember all parts of an experience equally. Instead, we tend to judge and remember experiences based on how they were at the end (and also at their most intense point), rather than on an average of the whole experience. The term was coined by Nobel Prize winner Daniel Kahneman, author of Thinking, Fast and Slow.
This rule suggests that you will remember even a painful or unpleasant experience more positively if the end of the experience is better relative to the rest of the experience.
Cold water
One of the first and most famous experiments highlighting the Peak-End Rule was published in 1993 under the title “When More Pain Is Preferred to Less: Adding a Better End”. The experiment involved subjecting people to the unpleasant experience of immersing their hand in very cold water. The first time around, people had to keep their hand in 14 °C water for 60 seconds. In the second trial, the same people did the same thing but then had to leave their hand in the water for an additional 30 seconds while the temperature was raised to 15 °C. The subject participants then had to choose which of the two trials they would prefer to repeat.
You might think people would obviously choose the first trial – 60, rather than 90 seconds of leaving your hand in uncomfortably cold water. But you guessed it: a significant majority said they would rather repeat the second trial. They chose more pain over less, but with a more pleasant ending.
Colonoscopies
Another study subjected colonoscopy patients to two different versions of this clearly unpleasant experience. Half the patients experienced a normal colonoscopy whereas the other half experienced a longer procedure but one that ended with three minutes that were less unpleasant than the rest. Essentially doctors left the tip of the scope in place without moving it. As a result, the last three minutes were less painful than the rest of the procedure.
As predicted, patients who rated the final few minutes of the colonoscopy as less painful and less unpleasant rated the entire experience as less unpleasant. Importantly, people were more likely to return for a follow-up colonoscopy if their overall memory was less unpleasant. Other research has also shown that people’s memories of painful medical treatments are strongly influenced by the level of pain experienced at the peak of the pain and during the last three minutes.
Childbirth
Many women say that while giving birth was the most profound experience of their lives, it was also the most painful. Does the peak-end rule apply here too? Researchers asked women in labour to rate their level of pain every 20 minutes from the time they arrived at hospital until the birth. The women were also asked two days later and two months later for an overall evaluation of the pain of childbirth using the same scale. And yet another tick for the peak-end rule. Women’s recollections of pain during childbirth after the event were largely determined by only two moments – the moment of peak pain and the moment of birth.
And prizes
And the peak-end rule doesn’t just apply to pain. Participants in a different kind of experiment were given free DVDs as a result of supposedly having won a raffle after donating to a charity. The DVDs given out were classed as more or less popular. People who received the more popular movies after the less popular ones were much more pleased with their raffle winnings compared to those who received the exact same DVDs in the opposite order.
Ending on a high note
So next time you’re planning a holiday or anything else that is likely to have highs and lows, plan for the best things to happen at the end. And don’t worry if things don’t go to plan. Chances are you won’t remember the bad bits anyway.
Now I just need to go on holiday so I can test the theory.
Espresso Science 