The technical definition
The peak-end rule suggests that we judge our experiences based on how they were at their peak (whether pleasant, unpleasant, frightening, etc.) and how they ended. The feeling of the peak and end dictates how we remember it.
Huh, what does that mean?
The peak-end rule unveils an interesting little corner of the human psyche. Have you ever had a relationship that ended terribly? You probably remember it in a negative light, but that might have a lot more to do with the way it ended than with the relationship itself. Childbirth is an obvious example. Mothers go through a very traumatic event, and they are usually able to remember the intensity of the worst pain, but they also view the event as something positive and wonderful. This is, of course, assuming the childbirth went well. The mother can remember the pain, but she also views the experience as a positive one because it ended in something wonderful: the birth of a child.
The impact the peak-end rule has on perception of time is also interesting. You spend your whole young life in school, but it could have just as easily been a few years as far as your recollections go. You will remember the apex and the end, and your memories of the whole will be determined by the feeling you had at the moment your brain considered to be the crest and the moment it ended. This is something doctors are beginning to pay more attention to because it is obvious that the way your experience ends has a profound effect on how you remember it. Therefore, there is more importance placed on aftercare and the end of medical relationships. This can affect the way you work and how effectively you work. It is a game-changer if you embrace the subtlety of the concept.
How can I use this in my life?
Be it a relationship, a job, or a single day, you have the power to make sure that you end an experience on a positive note. Instead of leaving a project unfinished, gritting your teeth through your commute, and battling the chaos you encounter when you get home, end your work day in a positive way, enjoy the time in traffic to relax and listen to music or a book on tape, and embrace the energy that meets you at the door. By ‘ending things on a good note’ you create happy memories that will last long past the event itself.
References
Kahneman, D. (1999). Objective Happiness. In Kahneman, D., Diener, E. and Schwarz, N. (eds.). Well-Being: The Foundations of Hedonic Psychology. New York: Russel Sage. pp. 3-25.