Why Time Seems to Speed Up as You Get Older

There is a moment in most Septembers when somebody says the year has vanished, and everyone in the room agrees a little too quickly. Nobody argues. The sensation is close to universal, and it gets stronger with age.

The clock did not change. What changed is the record the year left behind, and that is where the explanation lives.

Two kinds of time: in the moment and looking back

Psychologists separate prospective timing, how long something feels while it is happening, from retrospective timing, how long a past period feels now. They often disagree in the same direction. A dull afternoon in a waiting room crawls while you sit in it and leaves nothing behind, so a month of such afternoons collapses into a single vague blur.

Holidays do the opposite. Dense, absorbing days go quickly at the time and then feel enormous in memory, because there is so much to replay.

Almost everything people mean by "the years are flying" is retrospective. They are not reporting that Tuesdays feel short. They are reporting that when they look back, there is not much there.

Memory density: the year is as long as its contents

The leading account is that retrospective duration is estimated from the number of distinct, retrievable episodes in a period. More novel material means more markers, and more markers read as more time. The brain has no internal calendar to consult, so it reasons from the evidence available, which is memory.

This explains childhood elegantly. At eight years old, almost everything is a first: the first time you swim out of your depth, the first funeral, the first friend who moves away, the first bicycle you are allowed to take past the end of the street. Each first is encoded as its own event. A single summer stores dozens of them, which is why it felt like a geological era.

By forty, most weeks are variations on weeks you already have. The commute is the same commute. The kitchen conversation is the same conversation. Your brain, sensibly, does not store the four hundredth version of a familiar event as a separate memory. It updates a general script instead. That is efficient, and it is why last February is missing.

Novelty is doing the real work here, not youth. Move to a country where you do not speak the language and your first three months will feel longer than the previous three years, at forty just as much as at twenty.

The proportional theory

In the nineteenth century Paul Janet proposed a simpler mechanism: we judge a span against the total length of life so far. A year at five is a fifth of everything you have experienced. A year at fifty is a fiftieth. On that arithmetic, each successive year should feel smaller than the last, which matches the reported sensation neatly.

It is an elegant idea and probably part of the story, though it is hard to test directly and it cannot explain why one adult year feels longer than another. Memory density handles that better. In practice the two combine: the fraction shrinks, and the amount of distinct material per fraction shrinks too.

The reminiscence bump

Ask older adults to recall vivid autobiographical memories and the results are not spread evenly across the decades. There is a pronounced cluster from roughly the mid teens to the mid twenties, a pattern researchers call the reminiscence bump.

The most persuasive explanation is that this period concentrates firsts that also define who you become: leaving home, the first serious relationship, the first job, the first political argument you actually cared about, the music you will still defend at sixty. Novel and self-defining events get encoded richly and rehearsed often, so they stay accessible for decades.

It is worth reading the bump as a demonstration rather than as a loss. It shows what happens to your sense of time when life supplies continuous novelty. Nothing about the mechanism is restricted to being twenty.

Routine is the compression algorithm

Routine is not the enemy of a good life. It is how anything difficult gets done, and it protects attention from a hundred small decisions. But it is a compression algorithm applied to your own biography, and it is very effective.

Two mechanisms are at work. Repeated experiences merge into a script rather than a set of episodes, so they leave fewer markers. And familiar experiences require less attention, so less of them is encoded in the first place. You have driven a route home and arrived with no memory of the drive. Extend that to a whole season and you have the standard adult complaint about time.

There is a related point about deliberately unstructured time. Empty, slightly boring stretches are where the mind wanders, consolidates and makes connections, which is a case I made in why boredom is good for your brain. Boredom is not the same as routine. Routine fills the hours and leaves no trace. Boredom leaves the hours open.

What actually helps

The goal is not to make time crawl. It is to end a year with something in your hands. Everything useful here amounts to increasing the number of distinguishable events and paying enough attention to encode them.

• Break one routine a week on purpose. A different route, a different cafe, a different order of the morning. Small structural change produces disproportionate memory, because the deviation is what gets stored.
• Learn something with a visible edge. Skills create natural markers, because you can date the week you could not do the thing and the week you could.
• Do first versions of things. First time cooking that dish, first time on that trail, first conversation with that neighbour. Firsts are expensive to encode, which is exactly the point.
• Take photographs of ordinary days, not only special ones. Retrieval cues for unremarkable weeks are what most people are missing.
• Write two lines at night about what was different today. If nothing was, that is useful information about tomorrow.
• Protect single-task attention. Divided attention encodes poorly, so a distracted evening is a thin memory regardless of what happened in it.

A small daily learning habit fits this well, and not because it is virtuous. One genuinely new idea per day gives a week a texture it otherwise lacks, and it is the cheapest available source of novelty. I wrote about building the habit in learn something new every day.

Disclosure, since we are about to mention ourselves: MindSnap is our app. The two minute daily lesson exists for precisely this reason, and the interactive Turning Points scenarios put you inside a historical decision before revealing what happened, which is more memorable than being told. A single fact you can repeat at dinner is a marker on an otherwise indistinguishable Tuesday.

The takeaway

Time is not accelerating. Your life is being stored more efficiently, and efficiency and richness pull against each other. You cannot return to a state where everything is new, and you would not enjoy it if you could. What you can do is keep a steady supply of small firsts and attend to them properly, so that when someone says in September that the year went nowhere, you have a few honest answers about where it went.