What is the peak-end rule?

Discover how our memories are shaped by the most intense moments and endings of our experiences, and learn how to combat this common cognitive bias

You’re at a theme park. The line for the ride is 45 minutes. Your feet are aching, it’s hot, and there are far too many people around you. You’re feeling grumpy and wondering why you’re bothering to do this. But then you get on the ride. It’s thrilling. You reach the peak of the rollercoaster and let out an ecstatic roar. You step off, and the adrenaline is racing through your veins. You feel alive, and the irritation of the queue couldn’t be further from your mind.

This scenario illustrates the peak-end rule, a psychological bias where we judge an experience based on how we felt at its most intense moment (the peak) and its conclusion (the end) rather than an average of how we felt throughout the entire experience.

The model was proposed by psychologists Barbara Fredrickson and Daniel Kahneman. In their 1993 study, participants submerged their hands in 14°C water for 60 seconds. In the second trial, they submerged the other hand in 14°C water for 60 seconds, but then kept their hand submerged for an additional 30 seconds, during which the temperature was raised to 15°C. Participants were then asked which trial they would be willing to repeat. Surprisingly, most chose the second trial, despite spending longer with their hand in cold water.

Since then, the peak-end rule has cropped up in all sorts of areas of health and culture. Psychologists have found that patients rate painful medical procedures more favourably if the procedure is slightly longer but ends with a gradual decrease in pain. Brands use the rule to build a better customer experience – for example, you may forget the monotony of trudging around a showroom if you’re able to pick up an ice cream on your way out. But, crucially, the rule can also work the other way around.

Life Coach Latasha Baynham points to being made redundant. “Someone can spend years doing good work, building strong relationships, being promoted, and receiving positive feedback. But the shock of being told that their role is going, followed by weeks of back-and-forth negotiations and an exit that felt undignified, can start to dominate how they remember the whole experience,” Latasha explains.

“I also see it with interviews. Someone may answer nine questions well, but their mind goes blank on the tenth. That moment becomes the one they replay afterwards, especially if the experience ends with a rejection. Before long, ‘I struggled with one question’ has become, ‘I’m terrible at interviews.’ The difficult moment was real. The painful ending was real. But neither one necessarily tells the whole truth about the experience.”

The thinking behind why our brains do this to us is simple: we tend to have a better memory for more intensely emotional events than those that are less emotional.But, on top of that, research has also found that we aren’t always able to notice when an event is more emotionally intense than normal, making it difficult to recognise when our memories have been distorted.

As Latasha sees it, the first step to breaking free is to separate what actually happened from what you’ve decided it means.

“One practical way to do that is to divide a page into two columns,” she explains. “In the first column, write down the facts. In the second, write down the story you’ve attached to them. For example, after redundancy, the fact might be: ‘My role was removed.’ The story might be: ‘I’m not as good as I thought I was.’ Then go back and recover the rest of the evidence.

“Look at the whole experience, not just the worst moment or the way it ended. What did you achieve? What feedback did you receive? What relationships did you build? What did you handle well? What evidence doesn’t fit the story you’re now telling yourself?”

This is also where it can be helpful to bring in other people – a colleague, friend, or coach – who might be able to ground you, or ask questions to help you step back and evaluate the situation with more distance.

“Most importantly, don’t let one painful experience make your next decision for you. The aim isn’t to pretend the difficult experience didn’t matter, or force yourself to see it positively. It’s to stop one part of the story from becoming the whole truth.”

As fascinating as this fluke of psychology is, it can cause problems for us – even in cases where we’re remembering something in a more positive light than it was in reality. Being led by our emotions isn’t a bad thing (in fact, a world led by pure reason alone would be distinctly less human), but bringing awareness to the ways we can subconsciously rewrite our experiences can help us find a bit more balance and self-compassion.

You’re back at the theme park. It’s been a year, and you can’t wait to get to that ride again. You stride towards it and, bam, you’re hit with that hot, sticky, boring queue. Funny, you’d almost forgotten about that part. For a moment, you hover. Oh, here goes nothing: you join the back. Sometimes, a bit of cognitive bias comes in handy.