Just finished Thinking, Fast and Slow – and what an awesome book! I have already written a bit about the book in old posts and my previous post compares it to a couple of other popular behavioral science books. But if you find behavioral science and psychology the least bit exciting, you’ll probably love this book. As written before, it is not a book you just sprint through as one quote on the back of it states: “Buy it fast. Read it slowly. It will change the way you think!”

But just wanted to share a last anecdote from the book before moving on. Towards the end of the book there are chapters outlining the two selves; the experiencing and the remembering. Rather self explanatory, meaning the difference between what you actually experienced in the moment versus what you remember the experience as.

There have been some rather interesting studies in this area. For example people who have undergone different types of surgery has been equipped with devices that lets them rate the pain of the experience in small intervals during the surgery on a scale from 1-10. This is the experiencing self. Then afterwards they are asked to rate the pain of the experience as a whole again on a scale from 1-10. That is the remembering self.

What seemed to emerge from those studies was that it was not the total amount of pain – meaning the surgery with most pain during the experience that was rated as the most painful by the remembering self. Neither was it the total time under pain that emerged as the most painful, but instead it seemed to be the surgery where the pain towards the end was highest. If the pain tapered off towards the end of the surgery – people generally remembered it as less painful than they actually experienced it to be. This is to be known as the peak-end rule. The duration of the pain did not matter for the remembering self – known as duration neglect – the only real determining factor seemed to be how the surgery felt towards the end.

To test this Daniel Kahneman made a study where they subjected the participants hands to a very cold ice bath. As the surgery-studies, the subjects were equipped with devices to rate their experience during the trial and then afterwards asked to rate their experience. The first trial was 4 minutes in ice-cold water, then the next trial was the same 4 minutes in ice-cold water but then another 3-4 minutes where a little warmer water was released into the bowl without the subject knowing, so the temperature rose just slightly making the end less uncomfortable. Then finally they were asked for the third trial to choose whether to repeat trial 1 or 2 – and as you have probably figured, the vast majority chose to go with trial number 2 even though any rational observer would have chosen number 1.

This is peak-end rule and duration neglect at work. I find it so fascinating and amusing how these completely irrational factors plays into our lives. It also raises some interesting questions, for instance; should you prolong some surgeries artificially to taper off the pain towards the end thereby giving the patient a more pleasant memory of the surgery? Or in the less serious department; was your entire experience of a concert really ruined because it started raining at the end?

Trying to be aware of peak-end rule and duration neglect can make you less likely to get fooled by them. But as Daniel Kahneman writes somewhere; even though he has studied all these factors for decades, he still gets fooled by them from time to time – we just have to acknowledge and live with our irrational selves to the best of our abilities.