An interactive · On time

Where did the year go?

You've said it out loud. Here's exactly why it keeps happening — and how to make a year feel long again.

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A year used to be enormous.

Where did the year go?

Mechanism one · The shrinking slice

Mechanism two · Memory density

Your brain measures a year by what it remembers.

Childhood is crowded with firsts. Adulthood repeats — so it logs almost nothing, and the year vanishes. The emptiness is the point.

Childhood · dense with firstsThe road ahead · empty miles

It has two names

The shrinking slice is the proportional theory — Paul Janet, 1877. The empty road is memory: your brain stores novelty, not repetition.

In felt time, half your life is already behind you
by about age nine.

Not age forty. Solve the proportional model for the age where you've felt half of an eighty-year life, and it lands in single digits.

Your life, drawn

So — where are you?

Your age

Each tick below is an age. The bar is stretched by felt time — so each year is as wide as it actually felt. Notice how your early years take up most of the bar.

And you can fight it

One lever: novelty.

Every first is a memory your brain bothers to keep. Add firsts to a barren year and watch it stretch back out.

A thought experiment, not a measurement — there's no real formula for how much a memory lengthens a year. The dial below is invented. The direction it points is not.

Firsts this year 3

Roughly how long the year might feel, looking back

~1.0×

You can't add years. You can add firsts.

How much of this is real?

Contested

The shrinking slice is a tidy model, not a measured law.

The proportional theory is intuitive and old — but it's a formula that roughly fits the feeling, not something proven in a lab. William James said as much when he quoted Janet in 1890: the rule "cannot possibly be an elementary psychic law." Where felt time actually "begins" is a guess; here it's set to age one, and lifespan to eighty. Change those and the numbers shift.

Better supported

The empty road has real evidence behind it.

That your brain logs novelty and skips repetition is the sturdier idea. It's why a week of travel feels long in memory while a routine month evaporates — what Claudia Hammond named the Holiday Paradox, and why our most vivid memories cluster in the new-experience-rich years of youth. The "stretch" you dragged above is illustrative, not a constant: real memory doesn't scale on a clean dial.

Sources — verified

Paul Janet (1877). "Une illusion d'optique interne." Revue Philosophique de la France et de l'Étranger, 3, 497–502. The original proportional theory. Often misdated to 1897 — it isn't.
William James (1890). The Principles of Psychology, ch. 15, "The Perception of Time." Quotes Janet and adds the memory-density objection.
Claudia Hammond (2012). Time Warped: Unlocking the Mysteries of Time Perception. The Holiday Paradox, prospective vs. retrospective time, the reminiscence bump.
The model on screen. Felt moment at age t ∝ 1/t; cumulative felt time from a to T = ln(T/a); felt halfway age = a·√(T/a) ≈ 8.9 for a=1, T=80. Every figure here was computed, not recalled.

The year didn't get shorter.
You just stopped collecting
things to remember.

A long life isn't more years.
It's more firsts.

An interactive · On time