Why does happiness wear thin over time?

You might as well ask, ‘Why is time the best healer?’ One who lost his foot to a land mine or an arm to a threshing machine isn’t perpetually depressed. How does he get over the trauma? Why is the guy who was euphoric about winning that Rs5 crore lottery not in a perpetual state of euphoria? Why? Well, it’s all for the same reason why seasoned singing stars reserve their best for the latter half of their concerts! Now this needs a bit of clarification.

Researches in behavioural economics tell us that we humans are wired to discount the past. To show exactly how this works,
Nobel laureate Daniel Kahneman and others exposed some of their volunteers to some discomfort that they were asked to rate on a 100-point scale every five minutes. The discomforts varied in duration (15 to 35 minutes) and were proffered in ascending or descending level of discomfort, with degree of steepness of the discomfort level itself varying from one to the other.

The discomforts used varied from noise level to pressure of air from a nozzle to films with graduated unpleasantness, etc.
The results of these experiments were interesting. For the same overall level of discomfort, the ascending discomfort experience was considered much more unpleasant than the descending discomfort experience.

For example if the subject were exposed from, say 30 decibels to 160 decibels of noise gradually (ascending order of decibel) or if they were exposed from 160 decibels to 30 decibels gradually (descending order), the respondents overwhelmingly considered the first experience to be much more unpleasant than the second one.

Kahneman calls this the ‘Peak-End Rule’. According to the rule, how events peak (like ascending or descending) and the memory
retained from the end of an experience are what leave a more lasting impression on one’s mind. In other words, people do not necessarily evaluate the past based on the overall experience.

They go more by their most extreme experience (peak) and by the experience towards the end (end). Hence the Peak-End rule.
This could also mean that if you are making a presentation or a speech, how you end probably counts more than how you began.

If you are in an interview, your performance in the later moments will weigh much more than your performance early on. But this also means that even if you fouled up on your interview or your date early on, you can hope to recover by ensuring that you end the meeting or the date on a high note.

You can now see why seasoned singing stars reserve their best for the latter half of their concerts. You judge a company or mutual fund performance most by their most recent results. That they did extremely well two years ago counts for very little.

Events of the distant past are discounted fast. Unfortunately, this is also the reason that we tend to take the good turn done to us by a friend in the distant past lightly while putting disproportionately higher weight on his more recent behaviour.

The peak-end experience has its uses in human beings leading their lives with a sense of proportion. For instance, it is the peak-end phenomenon that also goes some way into explaining why one may feel terribly miserable if one were to lose a limb in an accident but eventually come to terms with the mishap. That’s probably also why lottery winners are not forever in euphoria and paraplegics not as unhappy with their lot as you and I may imagine.

For those watching paraplegics it is saddening because it is a recent experience, but for paraplegics and their families, this is a distant event and nicer things may well have happened since to soften the blow. Closely related to the above phenomenon is ‘hedonic impact’.

For example, winning of a lottery may render the subsequent happy events less exciting. And by the same token, a tragic experience may make one unhappy, but it also makes one tolerate subsequent experiences, which are less painful  better than someone who did not have a tragic experience.