Chip and Dan Heath say don’t wait for life’s defining events to come along – make them happen now. Here’s how

We all have defining moments in our lives – meaningful experiences that stand out in our memory. Many of them owe a great deal to chance: a lucky encounter with someone who becomes the love of your life. A new teacher who spots a talent you didn’t know you had. A sudden loss that upends the certainties of your life. A realisation that you don’t want to spend one more day in your job. These moments seem to be the product of fate or luck. We can’t control them.

But is that true? Not necessarily. Defining moments shape our lives, but we don’t have to wait for them to happen. We can be the authors of them. What if a teacher could design a lesson that students were still reflecting on years later? What if you had a better sense of how to create lasting memories for your children?

It is possible to create defining moments if we understand more about them. Our research shows that they all share a set of common elements. We start by asking: why do we remember certain experiences and forget others? In the case of big days, such as weddings, the answer is pretty clear – it’s a celebration that is grand in scale and rich in emotion. No surprise that it’s more memorable than a lesson on multiplying fractions. But for other experiences in life – from holidays to work projects – it’s not so clear why we remember what we do.

What if you had a better sense of how to create lasting memories for your children?

Psychologists have discovered some counterintuitive answers to this puzzle of memory. Consider an experiment in which participants were asked to submerge their hands for 60 seconds in buckets filled with frigid 14C (57F) water. (Remember 14C water feels much colder than 14C air.)

They were then asked to submerge their hands for 90 seconds instead of 60, but during the final 30 seconds, the water warmed up to 15C. The participants were then given a choice: would you rather repeat the first trial or the second?

This is like asking whether you’d rather be slapped in the face for 60 seconds or 90. Yet 69% chose the longer trial.

Psychologists have untangled the reasons for this puzzling result. When people assess an experience, they tend to forget or ignore its length – a phenomenon called “duration neglect”. Instead they seem to rate the experience based on two key moments: the best or worst moment, known as the peak, and the ending. Psychologists call it the “peak-end rule.”

In the participants’ memories, what stood out for them was that the longer trial ended more comfortably than the shorter one. (Both trials, by the way, had a similar peak moment of pain: close to the 60-second mark.)

So when we assess our experiences, we don’t average our minute-by-minute sensations. Rather, we tend to remember flagship moments: the peaks, the pits and the transitions.

What we don’t remember are the bits in between – sometimes there is little to distinguish one week from the next. We can spend weekend after weekend with our children, but in our memory all those times blend together.

Partly this is because there may be only a dozen moments in your life that capture who you are – those are big defining moments. But there are smaller experiences, too, in the context of a memorable holiday, romantic date or work achievement. Once we understand how we remember certain moments and why, we can start to create to create more moments that matter.

The Power of Moments by Chip and Dan Heath is published by Bantam Press on 5 October at £13.99. To order a copy for £11.89, go to bookshop.theguardian.com