The human brain seems to live its own life. We shouldn’t trust it very much – what we think is true and what really is true may be, and most frequently is, very different.
How exactly do we assess our past experiences?
Is our memory selective and is this why we choose to remember the event not as a whole but just some specific moments of it?
It seems that the answer to these questions most often is yes. In psychology this phenomenon is called a peak-end rule and it belongs to the category of cognitive biases. It means we remember experiences only at their most memorable moments (either pleasant or not) as well as the final experience. So it follows that we ignore the major part of the experience, everything that was before and after these particular moments.
The rule was discovered by a Nobel Prize winner Daniel Kahneman. For example, a person will remember a week-long holiday with even a single pleasant recollection and a delightful ending much better than a three-week long vacation with nothing exciting about it. It doesn’t mean the rest of that experience is lost though – we just don’t use it.
Also, two interesting observations with quite complicated appellations – duration neglect and temporal monotonicity – were made. Let’s try to explain them.
The peak-end bias works only for those experiences which are easily divided into the beginning / end. It is also not clear if it works for longer periods of time (research showed people do not seem to remember peaks and ends of even a day-long (yet continuous) experience. They tend to remember the overall impression better than the duration of the event.
It’s logical to suppose the more positive moments will be the better overall impression will become and vice versa.
However, duration neglect wins over temporal monotonicity. How exactly?
It turns out people prefer experiences with a tendency of positive moments to increase, even if the duration of negative experience will have to be longer and vice versa. They agree to sacrifice their time to worse feelings in the interim in order to get a final impression which will leave them more or less happy and satisfied.
The peak-end rule confirms people are inclined to think in terms of extremities rather than make moderate, sober judgments on the grounds of complex memories of the event.
Positive and Negative Memories
Since people always assess their past experiences (they are a natural basis of their knowledge, abilities and overall professional and personal identity) it’s crucial they remember the right things – things which can give them a complex overview of their activities and not just a one-liner perspective of a distorted reality.
The danger of the peak-end bias is that in case of a failure people stick to negative memories. For example, employees may recollect the failure and the difficulties of performing a task, at the same time forgetting the hard work and efforts that preceded it (which are often equally important to the professional competence, if not more). Needless to say, motivation can hardly flourish which inevitably influences productivity.
On the contrary, recollecting positive, pleasant moments results in boosting confidence and motivation and leaves one with a feeling “Yes, I did my best and it was worth it because the result is great”.
Some criticise the peak-end effect on the grounds it gives simplified explanations of perception of the event. For the sake of objectivity, it has to be said that all recollections shift from episodic to semantic memory in about a week. It means in the course of time we re-assess both peaks and ends. Moreover, emotions we had previously associated with them tend to tarnish.
Finally, the mood in which peaks and ends were memorized was really important. And that means that afterwards, when we experience quite different feelings, we again change our impressions.
While what critics say seems to be logical, it nevertheless is clear that the peak-end bias works at least in the short term. These key memories – the most vivid and the final ones – might explain how we assess our past experiences and predict which of them we will be willing to repeat or escape.