Why time seems to speed up as you get older

The feeling almost every adult has

Somewhere between Thanksgiving and New Year's, someone always says it: "Where did the year go?" Summer vacations that felt endless as a kid now seem to vanish in a weekend. The real question is whether time perception actually changes with age, and over which kinds of periods.

Read also: The Mandela Effect: why so many people remember it wrong and Why do we yawn when we see someone else yawn?.

What the study found

Marc Wittmann and Sandra Lehnhoff asked hundreds of people, from teenagers to older adults, how fast the last week, the last month, the last year and the last ten years had gone by. For short periods, age made almost no difference. The sense that the past decade had flown by did grow with age, up to around 50, and then leveled off.

Source: Wittmann and Lehnhoff, Age effects in perception of time, Psychological Reports, 2005.

Why it happens

A common explanation is novelty. Stretches of life packed with new experiences, like the first year of college, a move or a new job, leave many distinct memories, and looking back they feel long. Highly repetitive routines leave few distinct memories, so the period shrinks in recollection.

Routine shortens time in memory

Researchers at the Hebrew University of Jerusalem looked at how routine changes the sense of time. Across several studies, periods full of repeated activities were remembered as shorter than periods of the same length with more variety.

The logic is that the brain measures the past by what it stored. Weeks that look alike, same commute, same desk, same shows at night, produce few different memories, so they seem to fly by in hindsight. Adult life tends to be more predictable than childhood, when almost everything was new.

Source: Avni-Babad and Ritov, Routine and the perception of time, Journal of Experimental Psychology: General, 2003.

Time lived versus time remembered

A review in Psychonomic Bulletin and Review pooled dozens of experiments on how we judge duration. The authors separated two ways of measuring time: while it is passing and you are paying attention to it, and afterward, looking back. In the second case, the estimate depends heavily on how many changes and events memory recorded.

That explains a familiar paradox. A trip full of new things flies by while it is happening but feels long in memory. An afternoon at the DMV drags on in the moment and nearly disappears from memory afterward.

Source: Block and Zakay, Prospective and retrospective duration judgments, Psychonomic Bulletin and Review, 1997.

Can you slow time down?

Not the clock, but the memory of time. Breaking routine, learning something new and taking a few minutes to note what happened each week all give the months more landmarks. On a related topic, read why we don't remember our first years of life.