How long did it take for you to go to work today? No, not the literal answer. How long did it FEEL? Maybe it was a flash, or a blur, or a drawn-out slog of missed turns and stop-and-go traffic. But has the time it takes changed over time? If taken ‘literally’ again, then probably not. But your subjective experience of how long your drive to work or walk to school takes likely HAS changed. In fact, it’s probably gotten shorter. Why? Simply because you’ve done it a million times before. There was nothing particularly novel or worth remembering about your daily trek today. In fact, it becomes quite easy to begin the journey, enter auto-pilot mode, and then wake up again at your destination.

We all seek to optimize our lives. And in the most general terms, all reasonable goals seek to improve the quality or quantity of life, for either yourself or others¹. Good steps one can take to optimize their life range quite considerably: from planning vacations or getting more exercise to picking out gifts for friends or inventing new cures for diseases.

But there may exist an often unrecognized aspect to this ever-present challenge. And that is we ought not optimize our OBJECTIVE time spent ALIVE, but rather our SUBJECTIVE time spent LIVING. Compare a 90 year life that included 60 years spent married in the same town and same job, which, while perhaps very enjoyable and satisfying, may have flown right by much more rapidly than the 60 year life spent touring a myriad of cities, jobs, and relationships. Let us say that the former life had more happiness each (literal) second than the latter, in addition to living longer. And yet it is still possible, at least in my intuition, that more net subjective happiness was actually ‘experienced’ in the second life. Just because perhaps time was subjectively much slower, and so there was much more that was truly lived and enjoyed. But in order to compare these two hypothetical lives with any confidence, we must better understand our own subjective experience of time.

We are certainly aware that our subjective experience of time can vary dramatically. “Time flies when you’re having fun” is an adage alluding to this, and suggesting that subjective lifetime and happiness may actually conflict. Except, to no one’s surprise, mixing the noisy chaos of psychology with the nebulous nature of time makes it difficult to approach this question with great rigor. But we do know that there are a lot of temporal illusions that people have, including both the telescoping effect (where recent events are recalled as having occurred further back in time than they did, and more distant events recalled as more recent)² and Vierordt’s law (shorter time estimates are recalled as longer and longer ones as shorter)³. Together these two just tend to say that we are pretty bad at keeping track of time. There is also the ‘oddball effect’, where the initial and final event in a stream of identical events are perceived as having a longer duration⁴. Research also suggests that time seems to slow down during feelings of awe⁵ or fear⁶. And at least one paper argues that subjective duration is related to coding efficiency⁷, i.e. that less common or expected events are perceived as having longer duration. Here are a number of the other effects scientists have noted:

• Perceived temporal length of a given task may shorten with greater motivation
• Perceived temporal length of a given task may stretch when broken up or interrupted
• Time intervals associated with more changes may be perceived as longer than intervals with fewer changes
• Time durations may appear longer with greater stimulus intensity (e.g., auditory loudness or pitch)
• Subjective perception of the passing of time tends to speed up with increasing age in humans
• Stimulants lead to overestimation of time intervals by both humans and rats, while depressants and anesthetics lead to underestimation of time intervals

TL;DR:

So, if we were to take all of this and try to maximize our subjective experience of time, we would want to: do things that motivate us, try new things / switch what we do a lot, surprise ourselves, aim for higher intensity experiences, and drink coffee. Helpfully, most of these are pretty easily compatible with most other goals people set for themselves.

The most important question remains though: does this really matter? We are not literally increasing the amount of time we are living, are we? Just fooling our brains into thinking it was longer than it was?

Is there a difference?⁸

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A related and entertaining VSauce YouTube video: Illusions of Time

1. A deep dive into this in a future post. 👀
2. Telescoping effect
3. Vierordt’s law
4. Perceived duration of expected and unexpected stimuli
5. Awe Expands People’s Perception of Time, Alters Decision Making, and Enhances Well-Being
6. When time slows down: The influence of threat on time perception in anxiety
7. Is subjective duration a signature of coding efficiency?
8. And answering this may require diving into ‘consciousness’ itself. Better to be on the safe side, no? 😉