Meridia, episode 1 — written by Chris Lee

Why does time speed up as you age?

September 13, 2026

Summer lasted forever when you were ten. Now a whole year can disappear between one January and the next. Psychologists have measured the effect, and there are four explanations for it. They stack.

Meridia episode 1 thumbnail: a character running inside a hamster-wheel clock, titled Why does time speed up?

This is the written version of a 9-minute animated episode. Watch it on YouTube.

The three-minute test

In the 1990s, the psychologist Peter Mangan asked volunteers to count off three minutes in their heads, with no watch. People in their twenties came close. On average they called time at three minutes and three seconds.

People in their sixties called it at three minutes and forty seconds. Their internal clock ran slow, so the world outside ran fast by comparison. Forty seconds slipped past in three minutes and they didn't notice. Spread that over a year, or a decade, and you get the question every adult asks: where did the time go?

1. Each year is a smaller slice of your life

The oldest explanation is arithmetic. In 1877 the French philosopher Paul Janet pointed out that at five years old, one year is a fifth of everything you have lived. At fifty, it is a fiftieth. If your brain judges a year against the life it has already had, each new year has to feel shorter than the last.

Follow that math and the perceived halfway point of an eighty-year life falls somewhere in your twenties.

Janet's idea can't be the whole story, though. It predicts a smooth, steady speed-up, and life doesn't feel like that. The first week at a new job can feel like a month. Some years still feel enormous. Something else is involved.

2. Your memory stops recording

You have no direct sense of how long the past took. When you look back, your brain estimates duration from how much it remembers. A stretch full of memories feels long. A stretch with few feels short.

Psychologists separate how time feels while it passes from how it feels in retrospect, and the two often disagree. The writer Claudia Hammond calls one version the holiday paradox. A good holiday goes quickly while you're on it, then feels long when you remember it. Everything was new, so your brain stored a lot of it.

Childhood works the same way. A ten-year-old's ordinary Tuesday might hold a first bike ride, a bug they've never seen and a kid they've never met. Each one gets stored in detail. An adult's Tuesday of alarm, coffee, commute, screens and sleep looks like last Tuesday, so the brain keeps very little of it. At the end of the year there isn't much to look back on, and the year feels short.

3. The brain's clock slows down

Timing circuits in the brain rely on dopamine, the chemical also involved in motivation and reward. Research on interval timing, including Warren Meck's, links more dopamine activity to a faster internal clock and less to a slower one. Dopamine signalling declines as we age.

A slower internal clock makes the outside world seem to move faster. That fits Mangan's sixty-year-olds, who lost forty seconds without feeling it.

4. Fewer snapshots per second

The engineer Adrian Bejan has proposed a physical explanation too. As neural pathways age, signals travel through them more slowly, so the brain may take in fewer mental images per second than it did in childhood. Fewer images would make each hour seem to contain less. Bejan's account is a hypothesis, and researchers still debate it.

How to slow time down

All four explanations come back to attention and novelty. You can't change your age or your dopamine levels. You can give your brain more worth recording.

Big changes work, like travel or learning a skill that makes you clumsy again. Small ones work as well, because what matters is breaking the brain's predictions. Take a different route home. Sit in a different chair. Cook something you can't pronounce. The first day of a trip feels about twice as long as the third for the same reason: on day one, nothing is predictable yet.

Attention helps on its own. Stop and properly look at an ordinary moment, and your brain is more likely to keep it.

The years that vanished went quickly because nothing in them surprised you. How long your life feels depends less on the calendar than on how many days your brain decides are worth saving.

Next episode: why you can never remember the moment you fall asleep.

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Sources and further reading