Why Does Time Seem to Slow Down in a Life-Threatening Moment?

A car skids, a child slips at the edge of a pool, a ladder tips. Afterward, people often say the same thing: everything happened in slow motion. The experience is common enough that researchers have tried to test it.

How common is the feeling that time slowed down?

Very common among people who have faced sudden danger. In the 1890s the Swiss geologist Albert Heim collected accounts from climbers who had survived falls and reported that nearly all described an altered experience of time, according to a 2012 review by the philosopher Valtteri Arstila. More systematic surveys by Russell Noyes and Roy Kletti in the 1970s found that 75 percent of 85 accident survivors reported external time slowing down, and 68 percent reported their thoughts speeding up. The feeling was more common among people who believed they were about to die: 80 percent of that group, against 65 percent of those who didn’t.

Noyes and Kletti also noticed that surprise mattered. Hospital patients facing a threat from illness did not report the same speeded-up thinking, according to Arstila’s review.

Does time actually slow down, or does it only feel that way afterward?

The best-known test says it mostly feels that way afterward. In 2007, Chess Stetson, Matthew Fiesta, and David Eagleman strapped a wrist device they called a perceptual chronometer onto volunteers and dropped them, from 31 meters, into a safety net, a fall lasting about two and a half seconds. The device flashed digits slightly too fast to read under normal conditions. If fear truly sharpened perception, the digits should have become readable during the fall.

They didn’t. No participant could read the digits while falling. Yet when the same people were asked to estimate how long their own fall lasted, they judged it about 36 percent longer than they judged other people’s falls. The authors concluded that time-slowing is a function of recollection, not perception.

Why would a frightening moment feel longer in memory?

The explanation the authors favor is memory density. In a crisis the brain records far more detail than usual. When the memory is replayed, there is so much of it that the brain concludes the event must have taken longer. Eagleman has described it as everything getting written down. Ed Yong, summarizing the study, put it this way: time didn’t slow down, the volunteers just remembered that it did.

Do all researchers agree?

No. Arstila argues that the accounts survivors give include more than a stretched sense of time: unusually fast and clear thinking, calm, and purposeful action. He suggests that the brain’s processing genuinely speeds up in real emergencies, so that the outside world seems to slow in comparison, and that a brief, intense release of norepinephrine could be the mechanism. He also notes a limit of the 2007 experiment: a planned fall into a net is frightening but not surprising or truly life-threatening.

Ralf Buckley, drawing on decades of observing extreme-sport athletes, adds that experienced practitioners describe slow-time perception and precise action during narrow escapes, while beginners mostly report confusion. He suggests the state can be learned. These are hypotheses, and the authors themselves say the evidence is thin.

Does this have anything to do with near-death experiences?

It overlaps with them. Altered time is one of the features people commonly report in near-death experiences, and Noyes and Kletti’s survivors were, in many cases, people who believed they were about to die. See what people commonly report during a near-death experience and what the brain experiences when we die.

What does this mean for someone who lived through a frightening event?

Mostly that the experience is normal. Noyes and Kletti described it as a normal reaction to suddenly presented, life-threatening danger, according to Arstila. The vivid, slow-motion memory is the brain doing what it does under threat. If the memory keeps intruding or causes distress long afterward, that is worth talking through with a doctor or counselor.

This is general educational information, not medical advice. If you are grieving and these experiences are troubling you, a grief counselor or hospice bereavement service can help. If you are having thoughts of ending your life, call or text 988 in the United States.