“Ready steady slow”: time slows down when we prepare to move

By Ed Yong | September 4, 2012 7:00 pm

A baseball speeds from the hands of a pitcher, a slave to Newton’s laws. But in the brain of the batter who is watching it, something odd happens. Time seems to dawdle. The ball moves in slow motion, and becomes clearer. Players of baseball, tennis and other ball sports have described this dilation of time. But why does it happen? Does the brain merely remember time passing more slowly after the fact? Or do experienced players develop Matrix-style abilities, where time genuinely seems to move more slowly?

According to five experiments from Nobuhiro Hagura at University College London, it’s the latter. When we prepare to make a movement – say, the swing of a bat – our ability to process visual information speeds up. The result: the world seems to move slower.

At first glance, this might seem to contradict a now-classic experiment by David Eagleman. He threw volunteers off a tall fairground ride and asked them to stare at a special watch, to see if their perception of time would slow. It didn’t. They merely remembered the experience as being long and drawn out afterwards. (See my earlier post for the details.)

But there’s a critical difference between the two studies. Eagleman studied time perception while people were actually undergoing a crisis—in this case, falling to their possible doom. But Hagura showed that time appears more leisurely before an event, rather than during it—when we’re preparing to move, rather than moving.

Hagura first asked volunteers to press a key for as long as a white disc appeared on a screen. The disc would then be replaced by a hollow target. In some trials, the volunteers had to release their key and touch the target. In others, they were told to keep pressing the key. In every case, they had to say how long the white disc stayed up for, compared to all the previous trials in the experiment. Hagura found that the volunteers deemed the durations to be longer if they were preparing to move, than if they were planning to keep still.

Perhaps the volunteers who were about to reach out were just more excited or attentive? Not so. When Hagura changed the task from pressing (or not pressing) the target, to naming (or ignoring) a letter, the time-slowing effect vanished. Preparing to move makes the difference, rather than just preparing for any old task.

In a third variation, the white disc was replaced by two possible targets instead of just one. In some trials, the disc had a line that told the volunteers which of the two targets was correct, allowing them to prepare the right movement. In other trials, there was no line, and the volunteers had to make their move when the two targets appeared. As you might have guessed by now, they thought the white disc stayed up longer if they were preparing to move their arm in a specific direction, but not if they were simply waiting.

These three sets of results support the idea that time moves more slowly when we prepare an action. But they could also be explained in the same way that Eagleman’s results were: Time only seemed to pass more slowly because the volunteers remembered it doing so. But two final experiments suggest that, instead, preparing to move actually slows “the flow of visual experience”.

First, Hagura replaced the solid white target with one that flickered at different frequencies. The volunteers had to say whether it was flickering faster or slower than usual, compared to previous trials. If they were preparing to hit the screen, they said that the high-frequency flickers were slower than they actually were.

Second, Hagura showed his volunteers a stream of rapidly flashing letters, while they held a key. Each letter appeared for just 35 milliseconds, and the whole series went by in less than a second. Somewhere in the stream, there was a C or a G, but never both. Once the sequence had stopped, as before, the volunteers either kept holding their key, or touched the screen. Their task was to say whether they had seen a C or a G.

If the volunteers were preparing to reach out, they got the right answer about 66 percent of the time. If they kept still, their success rate was just 59 percent. By readying their arms to touch the screen, they were better able to spot their target amid the zooming letters. This difference was particularly marked if the C or G appeared towards the end of the flashing sequence – the longer the volunteers spent preparing to move, the slower time seemed to pass.

How does the slowing effect actually work? We don’t know. Hagura notes that there are certainly connections between the parts of the brain that encode the passage of time, and those that prepare sequences of movement. The details, however, are still unknown.

Why does the effect happen? Hagura argues that speeding up our powers of perception allows us to change, tweak and halt our course of action on the fly. He writes: “As expert ballgame players assert, being maximally prepared may allow ‘more time’ to perfect the hit.”

That would be a clear benefit, but Andrew Welchman, who studies perception at the University of Birmingham, wonders if there are any drawbacks. “You never get anything in the brain for free, so if you get better at one moment in time, you should get worse at another,” he says. “Take someone who moves a lot versus someone how moves little. They should both be calibrated to the same external time, so the one who moves a lot needs to have more ‘downtime’ to keep in step.” A bout of Neo-like bullet-time should be followed by a burst of perceptual sluggishness.

For example, Welchman says that when we move our eyes around, our visual sensitivity plummets immediately before, during and after the movement. This is called saccadic suppression. The standard interpretation is that we’re “filtering out the junk” – the “smeary visual signals” that we get when our eyes move too quickly. “But framed in light of this paper, it might be a way of resetting the clock so that the person stays calibrated to the visual world around them,” says Welchman.

Reference: Hagura, Kanai, Orgs & Haggard. 2012. Ready steady slow: action preparation slows the subjective passage of time. Biology Letters http://dx.doi.org/10.1098/rspb.2012.1339

Comments (13)

  1. Dale

    “Stay on your toes.”

  2. Roger

    Maybe this helps answer the question: why does the day seem unending when someone close to us has just died? Is it because we know that we too must soon move?

  3. Fascinating. This makes me wonder if the perception is a change in the brain’s sampling rate. Consider a film camera, running at 24 frames per second. Played back on a 24 frame per second projector, the image will appear in normal time. But what if you increase the amount of images taken in the film camera to 48 frames per second? Played back on the same 24 frame per second projector, the image will now appear half-speed. Could the “capture speed” and “playback speed” of the brain be independent of each other? Is this all that time really is? The more “frames” we capture with our senses, the higher fidelity and the slower time appears? If time is only the sampling rate, what does that say of the nature of that which is being captured?

  4. Dan

    If I recall correctly, Eagleman had become interested in the concept of fear causing time to slow down based on circumstances such as a priceless vase that seems to fall slowly before breaking. Hagura’s study is a useful adjunct to Eagleman’s work. Apparently, Eagleman was correct that people do experience a sense of time slowing down in such moments, but fear is not the primary driver of this phenomenon. Most frightening occasions involve attempted action to avert disaster – lunging to catch a vase, jumping out of the way of an oncoming car, etc. Fear is the most memorable aspect of the experience, whereas an attempt to take action seems to be an obvious byproduct of the circumstances. Eagleman’s hypothesis that fear was the driving force was reasonable, and it’s helpful that his experiment isolated fear in a circumstance that did not afford subjects an opportunity to take action to resolve the crisis. Otherwise, he may have reached a false conclusion that his hypothesis was likely true. If Eagleman had designed a study combining fear with the necessity to do something to resolve the perception of impending disaster, I wonder if his results would have been different.

  5. So does this mean that the scientists who said it’s impossible to see a fastball in time to hit it (and therefore batters hit them by anticipating the trajectory from the pitcher’s movements) were wrong?

  6. lee

    Mr Tony Youngblood you just blew my mind!

  7. thePoetGeo

    Research the batter’s EEG paying close attention to patterns of Gamma wave activity. Look for neuronal clusters oscillating together during these periods of synchronized firing

    Research using the hypothesis that parts of the batter’s brain are in synchronous resonance and are producing a ‘mind field’; and that the brain, instead of just being just biochemical thought processor, is utilizing groups of neurons as field generators.

    Stochastic resonance within this system is attuning the visual cortex to minute changes in movement.
    In brief, the batter is not just paying attention to the ball with his brain and its limiting electro chemical transition rates, but with an aspect of his mind: i.e. the processing is taking place within the level of field – quantum computational occurrence – mind as undergoing two distinct computational states – bio computer and quantum

    experimental results will differ wildly dependent upon the subject and subjects mental & physical states

    Try conducting the same on a Buddhist monks performing various martial arts

    See also – “Computing with waves; neurons as resonators” http://bcats.stanford.edu/previous_bcats/bcats04/html/nuallain.html

    Also, revisit the consciousness causes collapse theory (e.g. the act of observation affects reality directly)

    There is a Nobel Prize up for grabs here – if you can keep your budget non-military

  8. T. Brien

    Mr Youngblood, I don’t think it says anything about the nature of events. The events transpire at a given rate – a baseball moving at 90+ MPH – if the sampling rate in the brain increases it doesn’t change the speed of the baseball or the fabric of the universe around it. The only thing that changes is the perception of the individual. It is the perception that times slows down because you are sampling more “frames” per second than normal. Perception is not reality.

  9. Dave

    It would be a worthy use of time to check in with skydivers on this phenomenon. I made many years ago remembering numerous moments when I tried something new or unexpected and risky and the memories years later in many cases are video stills of frames sometimes not even separated by seconds. Adrenaline alters perception and that is enough to change the potential reality. Ask any NFL receiver about being in the moment. The nature of events may not change but if there is a switch to flip on capturing those moments, that is how we can learn more.

  10. rdiac

    T Brian and Dave are actually correct. You can test this yourself if you wish – you’ll need a cellphone[mobile], a bathroom and a mirror. Take multiple videos going over single activities. When you download them to your computer you can count the frames, and the test part is that ones’ prior estimations are at significant variance to outcomes when compared to each other. Dopey people probably shouldn’t try this.

  11. T. Brien, perhaps I was unclear in my hastily-composed comment, but I actually don’t disagree. I wasn’t implying that the underlying reality would change.

  12. Kinseher Richard

    The slow-down-perception of tennisball or baseball can be explained very simple:
    (sorry for my poor English)

    1) Make a film with a high-speed-camera of a ball who moves with a high speeds towards the camera (use the same position as the player would see the flight)
    2) split up the film and use only the frame*) in intervals of every 125 ms (milliseconds) over the film
    3) every frame*) has to be expanded to the duration/length of 125 ms, in the same order as they were taken out of the film > thus we have now a film who has the original length, but consists of sequences, each of 125 ms duration
    4) when you show this film to a player who had the ´slow-motion´-perception, then he will agree that this is, what he saw
    This means: the film has original length, only the movement is split up > time was not changed, only the perception

    And now to the topic perception; our perception works with very simple rules:
    “Rule 1 is: We are in a state of conscious awareness (= Stimulus pattern real-life(SPRL))
    On perception of a new mental and/or sensual impression (= stimulus pattern input (SPI)) => the brain will combine/add a comparable experience recalled from the memories (= stimulus pattern from memory(SPM)) => to form the new awareness (= stimulus pattern temporary awareness(SPTA)).

    Rule 2 is: compare the temporary awareness (SPTA) with the input experience (SPI) and reality (SPRL) for plausibility.

    Rule 3 is:
    A) When the compare is plausible, then the mixed experience (SPTA) is accepted as our new reality, the perception of awareness (SPRL). With this reality go back to rule 1 and start again with new impressions.
    B) When the compare is not plausible, then the level of awareness towards new and recollected impressions will rise when we focus our mind/attention onto the input of our senses – and our brain will go back to rule 1, to start again.”

    (The text of the 3 rules is a quotation from my book: Near-Death Experiences completley explained)

    Now you can understand the background of the slow-motion-perception: To an event (ball flight) which is well known from the training (=> many different experiences are stored in the memory) the brain will activate a comparable experience from the memory (with the anticipation of the future, thus we can react immediately) – this re-activated experience will become SPTA.
    But the ball will move on and when the plausibility examination is performed – the situation is not plausible (The ball is now in another position). Therefore the brain has to activate a new experience which fit to the new position of the ball. and so on and so on > this are experiences similar like the frames*) above, with a duration of 125 ms (in the example)

    I hope, my explanation is good enough to explain the phenomenon.
    P.S.: All our experiences are made, stored and recalled in PRESENT TENSE; therefore they are Standard Operating Procedures which allow a quick reaction to a certain situation, with the anticipation of the future.

  13. Mike

    “thePoetGeo” has some intriguing questions, also has anyone measured any physical vitals (Blood Pressure, Heart Rate, Metabolic Rate, etc.) during such experiments? Is there a way of measuring what kind of neural activity is focused on said task? Could the added activity give a better reaction time? Maybe a study with people where a faster reaction time is valued (Drag Racers or Fighters for example) since their reaction times can be quite short.

    If we can put focus more mental activity on a single issue, will it be better understood?

    Oh and Perception is not always Reality.


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