Does Time Run Faster When You're Terrified?

By Sean Carroll | April 26, 2011 11:10 am

Neuroscientists have all the fun. When we physicists think about the fundamental nature of time, it largely involves standing hopefully in front of a blackboard and writing the occasional equation, or at best sending clocks on strange journeys. All in the service of very good ideas, of course. But when I give talks about these wonderful ideas, I learn that what people care more about are down-to-earth questions about aging and memory. So not only do neuroscientists get to tackle those questions directly, but they do so by dropping people from tall buildings. How cool is that?

David Eagleman is an interesting guy, as a recent New Yorker profile reveals. Mild-mannered neuroscientist by day, in his spare time he manages to write fiction as well as iPad-based superbooks. But his research focuses on how the mind works, in particular how we perceive time.

I’ve written previously about how, as far as the brain is concerned, remembering the past is like imagining the future. Eagleman studies a different neurological feature of time: how we perceive it passing under a variety of different conditions. You might be familiar with the feeling that “time slows down” when you are frightened or in some extreme environment. The problem is, how to test this hypothesis? It’s hard to come up with experimental protocols that frighten the crap out of human subjects while remaining consistent with all sorts of bothersome regulations.

So Eagleman and collaborators did the obvious thing: they tied subjects very carefully into harnesses, and threw them from a very tall platform. The non-obvious thing is that they invented a gizmo that flashed numbers as they fell, so that they could determine whether the brain really did speed up (perceiving a larger number of subjective moments per objective second) during this period of fear.

Answer: no, not really. There is a perceptual effect that kicks in after the event, giving the subject the impression that time moved more slowly; but in fact they didn’t perceive any more moments than a non-terrified person would have. Still, incredibly interesting results; for example, when you’re afraid, the brain lays down memories differently than when you’re in a normal state.

Obviously, of course, these findings need to be replicated. If you’ll excuse me, I’m off to find some grad students and a tall building.

CATEGORIZED UNDER: Science, Time, Top Posts
  • astrothad

    Couldn’t you replicate this with grad students by fitting them with the number flashing device and then telling them they need to redo their thesis research?

  • Eric Habegger

    I think there are three problems with the experimental methodology of throwing people from a height and flashing numbers.

    1. The first problem is that the subject knows that it is an experiment and that they are ultimately safe. Sensory stimulus is very different from knowledge of a terrible fate about to befall you.

    2. Second, you have to have the illusion of hope in adjusting your fate. This is where time dilation
    occurs. ALL your attention is focused on trying to rescue yourself in real time as the process is unfolding. You notice every little thing that might allow you to change the trajectory of your fate. This involves enormous mental energy. Your brain is running at hyper velocity just as a high speed camera would. During playback in your mind then everything appears in slow motion.

    3. This is related to both 1 and 2. Once you are thrown off the platform the subject will know the end
    result is out of their hands. They also know that observing numbers will not get them out of the situation (which is not very dangerous anyway).

    This isn’t to say that you are always correct in assessing your ability to change a terrifying fate. I’m sure if a person accidentally stepped backwards off a tall building he WOULD experience time dilation even though he could no longer change his fate. It is the hope of changing your fate and knowing definitely the projected fate is horrible that puts your brain into high gear.

  • Neal J. King

    You could also try a slightly different experiment, that is more in conformance with your research grants, since you could describe it as testing the ideas of Einstein on relativity:

    “Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. THAT’S relativity.”

    You might not even need to modify the measuring devices.

  • jack lecou


    I’m not going to claim that this experiment is perfect, or at all the last word, but:

    Your 1. doesn’t seem to me like it’s necessarily very important. In my experience, the “time dilation” effect doesn’t particularly depend on a situation where there is literally mortal danger. Nor does conscious knowledge that a situation is harmless necessarily override instinctive biochemical responses. Further, Eagleman notes that they tested peoples responses to various trials, and this technique really did elicit a subjective experience of time dilation. I see no particular reason to believe that this isn’t the case. (Maybe there’s ANOTHER kind of effect that kicks in with the reeeeally deadly situations, but I don’t know why we need to postulate that, or how you’d go about testing it.)

    As for 2., again in my own experience, I think the trick-of-memory explanation actually makes a lot of sense. When I’ve done something like skid on an icy road or the like, I have certainly noted the perception of slow time, but I also can’t say that I honestly feel that my reactions were faster or that I actually had more ‘time’ somehow. I think my experiences were entirely consistent with those few seconds simply being much more intense, and NOT particularly consistent with my “brain running at hyper velocity”. (In addition, although I am not a neuroscientist, it seems to me that the biochemical explanation of a hormone-boosted surge in memory intensity seems much more plausible than some unknown mechanism whereby brain processing speeds up.)

  • Lab Lemming

    Because if someone throws you off of a building, the first thing on your mind will be to memorize numbers coming out of a gizmo…

  • Neal J. King

    If we ever find a neighborhood black hole, and graduate students are still dispensable enough, we could do a combined physics/psychology experiment and drop them into the black hole with measuring devices and radio transmitters.

    Get a verbal report on their observations of the rate of terrestrial events to see if their experience of them speeds up as expected. You’ll have to deconvolve the relativistic time compression from the psychological time dilation.

  • Eric Habegger

    @ Jack Lacou
    I not sure why you think a mortal fear inducing event would not create a more reliable experience of time dilation. Your example of skidding on ice seems to confirm that. I think possibly that the difficulty of creating a safe experience that induces that kind of fear tinged your opinion on this. I also don’t think the number flashing is a reliable indicator. I think what is being recalled must in some way be linked to the effort to escape the situation because the attention to those kinds of details are what seem to create the time dilation effect in the first place.

    An interesting experiment occurs to me which would be physically safe but perhaps not ethical. Have patients volunteer to undergo a pet scan of their brain for a scientific survey. While the person is incapacitated in the machine have an audible scripted event occur similar to what happened at Columbine. An example might be the sound of a man barging in and confronting the doctor the patient has just seen. A heated argument ensues with the man yelling that his wife died because of the doctor’s incompetence. The sound of the nurse comes in and tries to settle the man down, to no avail. Eventually shots ring out (from a gun shooting blanks) and screams are heard.

    All this time the person is undergoing a real brain scan with markers synchronized to the events happening. This would probably be too cruel an experiment to actually carry out but as a thought experiment it seems to me one could really find out a lot about energy expenditure and areas of brain activity involved in time dilation effects.

  • Harvey

    This was featured in an episode of WNYC’s Radiolab a while back. The segment starts around 4:00:

  • Colin

    This is really interesting; thank’s for passing it along.

  • Andrew H

    Does Time Run Faster When You’re Terrified? What does “run” mean? I suppose it means the subject’s perception of time. If this is the case, I believe most would concur there are as many perceptions of time as there are human emotions. There’s not a more popular and classic a saying as “time flies when you’re having fun”. I know spending a couple of hours with the in-laws is not the same experience as playing a video game or watching an enjoyable movie. Do my wife and I experience the same passage of an hour of shopping (to me, it’s as bad as the in-laws)? Do you experience time the same when your awake and conscious as you do when you’re asleep? To me, time isn’t something that’s linear. Our consciousness makes it so. To me, existence is like a vinyl record. Your conscious mind is like the needle of a record player. Although a record is complete in nature, songs play linearly from beginning to end. You’re conscious mind is playing out your existence to the beats and cycles of time. And like a record player, it can speed up and slow down.

  • spyder

    It seems to me that the experimenter would need to account for the various releases of neurotransmitters (HTP axis) stimulated by the endocrine system’s release of catecholamine hormones. Perhaps there is a need to reach out to the Mythbusters, who did conduct an experiment on mental focus after inducing large quantities of stress to the subjects (involving active target shooting).

  • Collin

    I wonder if they corrected for the fact that time goes faster when you are falling from a building.

  • Moon

    The last words are funny. Though that is a great honor to be your grad student.

  • ChuckWhite

    This experiment does seem to explain a lot. But, I doubt that fear is the driving factor. Here’s an example:

    While SCUBA diving with a group, I was told by a novice that his partner was being carried off by the current. As that only experienced diver on the boat, with 8 people gathered on the bottom, I had to dive 75 feet down to get the group up to the boat so we could find the guy being carried away by the current while 12 miles offshore. After checking, there were no air tanks onboard with enough air to get me to the bottom to get the group to surface, then get me back up.

    There was only one choice. Take the only tank with enough air to get me to the bottom and inform the group below, then depend on Boyle’s Law to expand what air was in my lungs as I rose from the 75 foot depth at a rate slow enough to prevent the bends.

    I experienced the time-dilation effect, though I was not fearful. I knew the biology and physics involved and had taken the precautions I could, given the circumstances.

    I suspect there is some relationship to adrenaline in the body, rather than strictly a reaction to fear. My experiences in the military tend to reinforce that view. When, in boot camp, you go “over the wall” on the night-fire course with machine-gun tracers two feet over your head, then crawl through a field with explosions going off on every side … you intellectually know you’re safe, but your adrenaline is pumping. I’d bet every Iraq Vet would tell you the same.

    I’ll bet on an adrenaline effect.

  • Missy Baldwin

    Time stands still in your sub-conscious mind , when your terrified. This gives the illusion of time going by quicker. How’s that for neurons ! ?

  • Tintin

    @ Neal J. King (6)

    Go back to GR 101. If you pass “GO,” do not collect $100.00!

    …and you too, Collin (12)

  • Neal J. King


    As I recall, the graduate student falling in will observe the events of the outside universe flash by, ending as s/he crosses the event horizon. These are subjectively witnessed events that can be reported (up until the very end).

    Of course the reports won’t get out until well after the events have occurred in the external universe; but what can be reported back is acceleration of the rate of passage of time, as experienced by the student.

    Kind of like the Blair witch project.

  • Jimbo

    Every guy knows the relativity of time on a blind date:
    (delta-t)/T <> 1 w/a beast !
    The watched pot never boils (nor the smoked variety), but if you leave the kitchen to watch a couple of plays on the NBA finals, the soup burns !

  • spyder

    I suspect that waiting out a severe tornado, that is massive in size, suspends time beyond any conscious awareness. Let’s send our good compassionate thoughts to all of those in the South.

  • Mark P

    I strongly suspect that it is, indeed, a memory effect. In normal life, for normal people, most everyday activities are not remembered particularly well. Events with great emotional impact are remembered very well, often in far greater detail than normal events. That gives a perception that a great deal occurred during that time because there is so much memory than for a similar period without the emotional content. I experienced a similar effect one year when I quit work and goofed off. I did a lot of very fun, interesting things that were unusual for me. In looking back, that year seemed far longer than a “normal” year. I think the reason is that I remembered much more about that period than I do about a period without unusual events.

    And, by the way, shouldn’t that be “Does Time Run Slower When You’re Terrified?”

  • Zwirko

    Weirdly, time passes quicker when doing nothing much at all.

  • Eric Habegger

    @ Swirko
    You are right, but I’m pretty sure from everyones well reasoned ideas here that it isn’t counter-intuitive. One just has to find a thinking “frame” in which it makes sense. If time within a person’s consciousness is measured by the number of events occurring in memory then equal time spans of consciousness with far different numbers of memorable events will actually be different in length..

    Geometrically, one could think of it like drawing a line between two distant points. First you have to invent what seems like an arbitrary rule. To draw that line you must connect individual points between those two endpoints that have an equal distance between each point. That is, you can’t just subdivide spaces between each point with less distance between them, like rational numbers can be.

    This means you must create an ever longer and more curvy line between those two endpoints as you fill the space between those two endpoints with more discrete sub points (memories). That curvy line representing perceived time will literally be longer than a straight line with no points (memories) between them.

  • Eric Habegger

    By the way, I think this way of thinking about time has important implications beyond thinking about the perception of time through consciousness. It seems to me, IMHO, that this elasticity of consciousness in terms of length can be used for the universe itself. This is what Sakharov talked about in the elasticity of space. As the universe gets bigger and cooler there may be less individual scattering events per unit distance because there is less particles containing energy per unit distance as the universe expands. This means that our present day less dense universe, just like the bored human consciousness as viewed from a local perception, experiences time flying by because there are less events occurring within the same parameter space.

    To relate that to the human perception of time. If we could have have existed at the dawn of the universe a lifetime of memories would have occurred during a single Planck length time interval. Time was moving exceedingly fast then.

  • Eric Habegger

    One more note regarding the consistency of Zwirko’s observation of time seeming to fly when nothing is happening. Anyone who has gone under the knife with a general anesthesia will know he is completely correct. My own experience was that when I awakened from the anesthesia it was like they put me under and immediately woke me up. To me it was as if no time had passed during the operation. So all these anecdotal observations about the conscious passage of time being related to memory experiences is completely consistent. Now I’ll shut up.

  • Joseph J Veverka

    No, time only runs faster when your in a hurry.

  • Eunoia

    Being someone who also races motorcycles, may I suggest an experiment like this :-

    While racing on the limit (which dilates subjective time), get the rider to bite on a contact switch every perceived 3 seconds. Biting would leave the hands and feet free for controlling the bike as usual. Record the bite intervals.

    Repeat when riding 25% below the limit (compare lap times).
    I expect the results to differ between racers, depending upon their abilities,
    but to be consistent for each racer. Record the heart and breathing rates too.
    My pulse goes up to 150+ and I lose a couple of pounds per race, just for the record.
    Time dilates most for me when braking for a corner while leaning the bike over, even more so when sliding, and races past on the (boring) straights.

    I’m sure you neuro-nerds could improve on this experiment design; go ahead, it’s just a suggestion :-)

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About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] .


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