April 14, 2025 • 43 mins
What does The Matrix tell us about the brain and time perception? And what does that have to do with champion bicyclists, hidden data, elementary particles, secret murderers, or time machines? Today’s episode is about slow motion: what’s going on in the brain, and why we are so mesmerized by it. Whether watching a sword battle, basketball dunk, or sprinters, we're pulled to slow motion like moths to flame... but have you ever wondered from a neuroscience perspective what that’s all about? Me too, and hence today’s 100th weekiversary episode.
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Episode Transcript
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Speaker 1 (00:05):
Why do we love to watch slow motion in the movies?
What do Bonnie and Clyde or Inception or the Matrix
tell us about brains and time perception? And what does
any of this have to do with unmasking hidden data
or champion bicyclists or elementary particles or murderers or HG
(00:26):
Well's time machine. Welcome to Intercosmos with me David Eagleman.
I'm a neuroscientist and an author at Stanford and in
these episodes we dive deeply into our three pound universe
to understand some of the most surprising aspects of our lives.
(00:54):
Today's episode is about slow motion and what's going on
in the brain and why we are attracted to it.
So we all know that if you go to any
random blockbuster, you're really likely to see some of the
sequences in slow motions gets employed to accentuate the choreography
of gun battles or sword fights, and of course it
(01:17):
doesn't even have to be fighting. You might see it
in a shot of a basketball dunk, or a flipping car,
or sprinters crossing the finish line, whatever the shot. What
we get to witness is fluidity and elegance in a
visually captivating spectacle that has become a hallmark of Hollywood,
(01:40):
and it goes even beyond action movies. Even in dramas
and romances. We see slow motion get leveraged to capture
intimate emotional moments. We savor the subtleties of someone's eye
movements or facial expressions or body movements. We understand something
about the unspoken longing and restrained passion between two protagonists,
(02:05):
or we watch a tear fall, or we see the
moment that someone has an unexpected revelation.
Speaker 2 (02:13):
So we see slow motion all the time.
Speaker 1 (02:15):
But have you ever wondered from a neuroscience perspective what
that's all about and why brains love it so much? Yeah,
me too, and hence today's podcast. So let's start by
zooming way out. When did slow motion really start in movies?
You may be surprised to know that the era of
(02:36):
slow mo didn't really begin until nineteen sixty seven. And
what stuns me about this is that by nineteen sixty
seven we already had supersonic flight and bionic limbs and
credit cards and digital music, and the space race was
in full swing, but nobody was using slow motion until.
Speaker 3 (02:59):
I thought, I have an idea about the end that
should be like a spastic ballet, and that was the image.
Speaker 1 (03:09):
That's Arthur Penn, the director of the nineteen sixty seven
film Bonnie and Clyde. This was a big Hollywood blockbuster
that dramatized the real life crime spree of Bonnie Parker
and Clyde Barrow, and the stars were Fade, Done Away
and Warren Batty. So Bonnie and Clyde were a young
couple who became bank robbers during the Great Depression, and
(03:32):
in the movie, they travel across the country with their
growing gang and their crimes escalate, and this attracts the
relentless pursuit by law enforcement, which culminates in a violent ambush.
Speaker 3 (03:47):
And then so I came to the technicians and I said, look,
this is what I want to get.
Speaker 2 (03:52):
They said, you can't do that.
Speaker 3 (03:54):
I said, I want four cameras. I want them running
at different speeds, I want them ganged together, and I
want to roll them all at the same time.
Speaker 1 (04:07):
And so that's what happened. In the final scene, the
cinematography decelerates into a balletic slow motion as Bonnie and
Clyde meet their bloody end. Under a hailstorm of police bullets,
so as they experience their final moment, the audience is
(04:28):
given some extra seconds to be witnessed to it. Now,
this really shocked a lot of people. Critics called Arthur
Penn's slowed down death scene gratuitous and callous, but.
Speaker 2 (04:44):
The idea caught on.
Speaker 1 (04:46):
Bonnie and Clyde had opened the door to slow motion
and it's never been shut since.
Speaker 2 (04:52):
Now.
Speaker 1 (04:52):
By the way, it's not that the technology was new.
The method for slow motion movies came into being in
nineteen o five four when the Austrian physicist August Musker
invented the technique. So what's the technique. You just speed
up the recording camera so you're capturing more frames per second.
(05:12):
In this way, what you're doing is capturing faster changes.
The time in between each picture is shorter than normal.
So then when you play the film strip back at
regular speed, like twenty four frames per second, then the
scene appears to be in slow motion because the change
(05:32):
from one frame to the next is very small. This
was initially just getting used for scientific purposes to slow
down processes that you can't see well with the naked eye,
but eventually slow motion was adopted by filmmakers to enhance
visual storytelling. Now, before we go on, I want to
make sure we have a clear distinction between slow motion
(05:55):
in movies and the impression that you might have if
you have experienced a life threatening situation and it feels
like the event took a long time. Is this because
the frame rate of your brain changes.
Speaker 3 (06:11):
No.
Speaker 1 (06:12):
Ninety nine episodes ago, I talked about the impression we
have of very frightening events having taken a long time.
This is something I first experienced as a child when
I fell off of a roof. I have very clear memories,
and it feels like the whole thing took a few seconds,
even though I can calculate that it only took point
(06:32):
six seconds to get from the top to the bottom. Now,
it turns out that this observation about scary events seeming
to last longer. This is at least one hundred years
old in the scientific literature, although I imagine that people have
noticed this from time immemorial. But my laboratory was the
first to run experiments on it to see if it
was an issue of a faster perceptual frame rate, which
(06:57):
again is how a movie camera captured slow motion or instead,
does it happen to us? Because of the laying down
of denser memories and the retrospective estimate of how much
time had passed. We ran experiments by presenting information at
a faster rate than a person could normally see, and
(07:20):
then we put them in a very scary situation where
we dropped them from one hundred and fifty foot tall
tower and they were caught in a net below. If
a person is like a camera speeding up its frame rate,
then they would be able to easily see the information
we were flashing at them. But our results indicated that
the slow motion effect was a.
Speaker 2 (07:42):
Trick of memory.
Speaker 1 (07:43):
In other words, when you're in fear for your life,
your brain writes down dense memory. It's capturing everything it can,
whereas normally your memory is very leaky. So when your
brain then asks what just happened? What just happened and
reads it out all those dense memories, it estimates that
the event must have taken longer. Your brain has all
(08:08):
these rich memories, let's say, the hood crumpling and the
rear view mirror falling off, and the expression on the
other driver's face and so on, And given that opulence
of memory, your brain calculates that the whole event must
have represented a slightly longer duration. In other words, what
happens during a scary event is a totally different mechanism
(08:32):
than slow motion video. Now, when I published our findings,
some people said to me, Hey, I don't think your
conclusion is correct because I had a life threatening car
accident and I know what I experienced. So I said
to them, Okay, but the guy in your passenger seat
who was yelling watch out, did it actually.
Speaker 2 (08:51):
Sound like he was saying.
Speaker 1 (08:57):
Because if not, that means that time is not actually dilated.
Because if you are recording something with a faster frame rate,
then when you play it back out, everything is stretched.
So with your experience of time dilation, it's not an
issue a faster frame rate like a movie camera, but
(09:17):
instead of denser memory. Please listen to episode one of
this podcast for much more about that. And the reason
I'm telling you about this now is because we're going
to return to this in a few minutes. For now,
let's get back to filmmaking, where the mechanism is very straightforward.
You just take more frames per second. Now, I said
(09:39):
that Bonnie and Clyde was the first major movie to
use slow motion, but there were actually experiments with it
before that. One of the earliest uses in cinema was
in an epic silent film called Intolerance in nineteen sixteen.
This was made by a director named D. W. Griffith,
who was experimenting with all millions of techniques of filmmaking
(10:02):
and used slow motion just a little bit to accentuate
dramatic moments and heighten emotional tension. But two World Wars
that over half a century passed before I was used
in Bonnie and Clyde, in part because the technology had
to advance to make slow motion more accessible and versatile.
By the nineteen sixties, people were building high speed cameras
(10:25):
which were capable of capturing hundreds of frames per second
and eventually thousands, and this is what allowed filmmakers to
push new boundaries of representing time and creating effects that
audiences were captivated by. And the nineteen sixty nine film
The Wild Bunch, two years after Bonnie and Clyde, really
(10:46):
helped popularize the technique. And now, of course we don't
even think about it much because it's a staple of
modern filmmaking. For example, I recently watched a movie called Wanted,
which uses super slow motion every time there's a gun battle.
Where you may remember Christopher Nolan's movie Inception, which has
these beautiful slow motion dream sequences, especially in the kick
(11:11):
moments where they're transitioning from one reality to another. So
increasingly since nineteen sixty seven, movies use time warping all
the time, and the success of this approach has overtaken
commercials and music videos, and it's a standard tool on
our cell phones. And in fact, you can tell when
something has become a staple because then it shifts into
(11:33):
the focus of the comedians. Some years ago, the comedian
Dave Chappelle did a skit in which he was proving
that everything quote looks cooler in slow motion. So in
the skit, he walks into the laundromat and says hello
to a kindly middle aged woman who is preparing her laundry,
and she takes off her sweatshirt so she can add
(11:54):
it to her hamper, and it's all very innocent and laundromaty,
and then he says, let's replay this video in slow motion,
and now everything changes from mundane to sexy in the
slow motion replay. The woman lifts the sweatshirt over her
head and is suddenly replaced by a beautiful young model
(12:14):
who tosses her hair in a vigorous breeze, and she
and Dave Chappelle start dancing around each other as the
wind blows. So this skit cracked up the audience. But
this just underscores our question, what is the appeal of
slow motion? Why do we find it so attractive? I
propose four reasons. The first is the increased esthetic appeal.
(12:40):
When you decelerate time, you can experience so many more
details of this scene. And just like Dave Chappelle noticed,
even ordinary moments get turned into extraordinary visual spectacles. And
this is because by slowing down time, you highlight the
intricate features of a scene. The human eye is naturally
(13:01):
attracted to detail, and slow motion allows us to appreciate
the subtle nuances of a character's movement, or the play
of light and shadow, or birds exploding out of a tree,
or the look on someone's face as they turned to
see that their lover has left. So you remember the
(13:22):
Matrix which came out in ninety nine, and you certainly
remember this bullet dodging scene where Neo bends backward to
avoid a series of bullets fired at him, and this beautiful,
slow sweeping shot captures the fluidity in the wondrous precision
of his movements. The scene could never have worked at
(13:44):
normal speed because the key was how he was making
a move that was not normally physically possible, and the
otherworldly nature of this required immersing us to have time
to really take it in. Just like Bonnie and Clyde,
the slowness heightens the tension and the drama. We the
(14:05):
audience get to squeeze every moment out of the scene
rather than have it zip by.
Speaker 2 (14:12):
While we're reaching for our popcorn. And again, it doesn't
have to be action scenes.
Speaker 1 (14:16):
Look at Terrence Malick's film The Tree of Life or
Darren Aronofsky's Requiem for a Dream. The slow motion allows
viewers to fully absorb the emotional weight of a scene. Okay,
(14:48):
so increasing the aesthetic appeal, that's the obvious reason, But
from a neuroscience point of view, I'm going to suggest
there are deeper reasons why slow motion works. And this
leads to my suggestion two, which is that slow motion
film serves as a proxy for denser memories. So a
(15:08):
few moments ago, I told you what happens during a
life threatening situation. Although you don't actually see the event
unfold in slow motion, the denser memories that you have
make it seem like it must have been that way
in retrospect, because there's a greater than normal amount of
detail when the memory is read back out. And I
(15:30):
suggest that slow motion film is a stand in a
substitute for this extra dense memory. By watching a movie
scene slowly, we get to enjoy a rich experience with
plenty of time to dwell on all the details that
would normally streak right past us. We have the opportunity
(15:52):
to attend to the details and commit them to memory,
just like we have after a real life high adrenaline moment.
In other words, slow motion film recreates the sensation of
grasping all the details, and this explains the natural partnership
of slow motion videography.
Speaker 2 (16:13):
With high adrenaline moments.
Speaker 1 (16:15):
It's no accident that the first time it really got
used was the ambush death scene of Bonnie and Clyde.
The director Arthur Penn said in an interview quote the
intention there was to get this attenuation of time that
one experience is when you see something like a terrible
automobile accident end quote. And giving the audience a heightened
(16:38):
ability to catch and remember details worked well, and it's
become a standard signature of high stakes moments. Arthur Penn
went on to say in nineteen eighty nine, quote, God
knows we've been imitated thousands and thousands of times.
Speaker 2 (16:54):
Now.
Speaker 1 (16:55):
Every time you see someone attempting violence, they go into
that basics slow motion end quote. So my assertion is
that when we witness a moment unfold bit by bit
in the movies, we get to appreciate its import as
though we were experiencing the high adrenaline moment ourselves. But
(17:17):
not all interesting slow motion video involves high adrenaline situations,
So there is more to our love of it. And
this leads us to my third suggestion for the success
of slow motion, which is that it extends human perception
by unmasking hidden data. It allows the revelation of data
(17:38):
that's hidden in the folds of time, just like a
microscope allows us to appreciate the details of a fly's wing.
And I'm not just talking about action sequences here or
neo's unusual movements in the matrix, there's much more that
can be unmasked. Consider something like microexpressions. These are fast
(17:59):
movements of facial muscles that pass rapidly and unconsciously over
people's faces. Now, everyone's face does this naturally all the time,
but you can't really see someone else's micro expressions because
they're too brief. You're not aware that you are making
micro expressions, and someone watching you isn't consciously aware that
(18:20):
you did it. But it turns out that micro expressions
can carry information and can reveal secrets, including things like deception.
For example, you may remember the story of Susan Smith,
who claimed that her children had been kidnapped in a carjacking,
when in fact she had drowned them. For several days,
(18:41):
she was on the TV news pleading for help in
finding her children, but some colleagues of mine claimed that
a slowed down version of the video revealed micro expressions
that suggested she was lying about the whole event. The
idea is that slow motion video unmasks the world of
(19:01):
these temporally hidden facial clues, and by unveiling things that
are undetectable by consciousness, slow motion can allow not just
temporal sleuthing but temporal intimacy. Consider this passage by the
British sports writer Matt Rendell about the Tour de France
winner Marco Pantani. Writing about the use of super slow
(19:26):
motion cameras in sport, Rendell wrote, what I think is
one of the most beautiful passages in sports writing. Here
it is read by the actor Sean Judge.
Speaker 4 (19:36):
Now, as he arrives towards victory and the Giro Dtalia,
the camera almost caresses him. The five seconds between the
moment Marco appeared in the closing strait and the moment
he crossed the finish line are extruded to fifteen and
during seconds ba image frames his head and little else,
(19:58):
revealing details in visible in real time and at standard resolution.
A drop of sweat that falls from his chin as
he makes the bend, the gaping jaw and crumpled forehead,
and lines beneath the eyes that deepen as Marco rings
still more speed from the mountain. Then, and it must
(20:22):
be the moment he crosses the line. He begins to
rise out of his agony. The torso rises to vertical,
the arms spread out into a crucifix position, the eyelids
descend and Marco's face lifts towards the sky. It is
a moment of transfiguration visible only in super SlowMo or
(20:46):
in still and only the best of the finish line
photographers catch it. Super SloMo shows us something we could
never otherwise see, involuntary gesture Marco never chose to reveal,
perhaps because without super slow MOO technology he cannot know
(21:07):
he makes them. The public knows more about Marco than
Marco himself, a truth we are tempted to imagine, and
one that has nothing to do with the race outcome
as such, for the pictures frame out the finish line
in the clock and show nothing of his work rate,
muscular toil, or the relative positions of the riders that
(21:30):
yield the race result. Instead, we find ourselves looking into
Marco's face the way a mother and her baby might,
or lovers at the moment their affection is first reciprocated.
Speaker 1 (21:46):
So slow motion allows us to pick up on the
world that would otherwise rush past us. And in this
slow world we get to luxuriate in the otherwise invisible
detail with which we're always surrounded but we never see.
And now we're ready from a fourth point. Slow motion
(22:08):
video holds our attention by violating expectations. So during a
lifetime of experience, your brain develops deeply wired expectations about
Newtonian physics. So when a ball gets thrown to you,
your brain unconsciously uses these internal models to predict where
(22:29):
and when it's going to go, and you move your
body in your hand to the right spot. These models
are so ingrained into our nervous systems that if you
lob a ball to an astronaut floating in zero G,
she will move her hand to the wrong spot. She'll
move to catch it as though she's in a normal
one G environment. So part of the high level of
(22:52):
engagement during slow motion comes from a violation of these
expectations about physics. Imagine you're watching the matrix and you
observe Trinity leap into the air to kick an agent.
Your brain makes unconscious predictions about exactly when she's going
to come back down. But to your brain's surprise, time
(23:17):
slows down and Trinity hangs in the air longer than expected.
Your expectations about when she's going to hit the ground
have been violated, and this draws us in. Our brains
zoom in on this because attention is maximally attracted to
whatever we predict incorrectly. Conversely, when everything goes according to plan,
(23:40):
we don't pay any attention at all. We are fond
of slow motion video because it engages our attention. We
constantly get the temporal predictions wrong, and so we are
perpetually on alert. In fact, I did a very surprising
experiment on this some years ago. I started with this
hypoc prothesis that your internal model is always calibrating itself,
(24:04):
keeping itself tuned up by comparing against the physics of
the real world. So if it's running too slowly, it
watches the ball hit the ground and realizes that its
prediction was just slightly behind, so it speeds up its expectations.
And the same if it watches the ball and it
realizes that its prediction was just slightly ahead, then it
(24:26):
slows itself down. So it uses the outside world as
the ground truth to keep itself nicely calibrated. Now you
might think, how would you ever prove a hypothesis like that, Well,
here's how I had people compare the durations of two
brief flashes on the screen. So on the screen you
(24:48):
see a little circle that goes flash and then a
moment later, another little circle that goes flash. And on
every trial, I'm slightly tweaking the duration so that one
is slightly longer than the other, and you just say
which was longer than which? Okay, now here's the trick.
I have people watch a video, for example, a camera
(25:08):
that follows the cheetah sprinting across the serengetti. Now, if
I just superimpose one flash and then the second flash
on top of the video, you have no trouble saying
which one was longer than which. But now I do
something special. At some point in the video, it suddenly
goes into slow motion. Then you might know that when
(25:29):
cheetahs run, all four of their legs come off the ground.
Speaker 2 (25:33):
So now you're seeing this sleek.
Speaker 1 (25:35):
Animal floating in the air and you're waiting for his
front pause to hit the ground. But now that we're
suddenly in slow motion, your time prediction is off. You
expected his legs to hit the ground, but they haven't yet.
Speaker 2 (25:50):
And because we evolved.
Speaker 1 (25:51):
In a world with no such thing as slow motion,
your brain's only choice is to assume that the mistake
is its own, and it compensates by slowing down its expectation. Now,
how do I know the brain does this. It's because
I can see how you judge the duration of a flash.
(26:11):
During the sudden slow motion, the flash now appears to
last a shorter time, about twenty seven percent shorter.
Speaker 2 (26:20):
Why.
Speaker 1 (26:22):
Roughly speaking, it's because your brain is forced to slightly
tweak its estimate of the pace of time during the
slow motion bit. Think of it like a clock ticking
more slowly, and now the flash covers fewer ticks, and.
Speaker 2 (26:38):
So it is judged to last less time.
Speaker 1 (26:42):
I did various control versions of this experiment in which
I shuffled the frames, or I shuffled all the pixels,
or I ran the whole thing upside down, and in
all these cases there was no distortion of the apparent
duration of the flashes. It only happened when the future
position of objects was predictable by physics. So let me
(27:04):
just summarize this. When your brain is watching any scene,
it's making predictions about where things will be, and if
the scene suddenly changes speed, then your internal model will
predict incorrectly. But I suggest the nervous system can eliminate
these feedback prediction errors with a simple trick by modifying
(27:27):
its estimated speed of the flow of physical time.
Speaker 2 (27:32):
It's a very subtle.
Speaker 1 (27:33):
Change, but it has measurable perceptual consequences which are exposed
by this novel time distortion illusion. Okay, that was a
little technical, but it's one of my favorite experiments. Now,
we've been talking all about slow motion, but on the
flip side of slow motion, there is a world unmasked
(27:53):
by fast motion. Think about quickly blossoming flowers, or imagine
the the arterial traffic patterns of cities, or watched the
laminar rush of clouds across the sky, or observe the
way that the sun drops like a ball behind the
mountain and the world dims as though by.
Speaker 2 (28:14):
A dimmer switch.
Speaker 1 (28:16):
So fast motion reveals secrets not so much in the
domain of human facial expressions, but instead in the dance
of the very large. So let's take a look at
(28:43):
the kind of descriptions you can generate when speeding up
the world. In eighteen ninety five, HG. Wells published The
Time Machine. He did this as a serial novel in
a magazine. It's one of the earliest and most influential
works of science fiction, in part because it introduced this
concept of a time travel device, which became a staple
(29:05):
in the genre. But it's beautifully written, and we can
see the imagination of fast time when the unnamed time
traveler builds this device and travels to the very distant
future of the year eight hundred and two, thy seven
hundred and one. Here's the part I want to share
with you, when he cranks the lever down on the
(29:27):
machine and gets going. This passage is read again by
actor Sean Judge.
Speaker 4 (29:33):
As I put on pace, night followed day like the
flapping of a black wing. I saw the sun hopping
swiftly across the sky, leaping it every minute, and every minute,
marking a day. The slowest snail that ever crawled dashed by,
too fast for me. Presently, as I went on, still
gaining velocity, the palpitation of day and night merged into
(29:53):
one continuous grayness. The jerking sun became a streak of fire,
the moon a fa interfluctuating band. I saw trees growing
and changing like puffs of vapor. Huge buildings rise up,
faint and fair, and pass like dreams. The whole surface
of the earth seemed changed, melting and flowing under my eyes.
Speaker 1 (30:16):
So in the same way, that slow motion allows us
to see details that we would not otherwise catch. Fast
motion plays that same game. It's no surprise, then, that
a very engaging style of cinematography is to rapidly alternate
between speeding and slowing. Think of the battle scenes in
(30:37):
the movie three hundred. As the Spartans charge, the camera
captures their ferocity in real time, the thunder of their
shields clashing and the spears piercing, And then suddenly the
world slows and every movement stretches into a balletic display
of destructions. Sweat glistens, blood arcs gracefully through the air
(31:00):
like crimson silk. The slow motion lingers on every ripple
of flash, every grimace of pain, before snapping back to
faster than normal speed. You see this explosion of chaos
and bodies tumbling and dust swirling under the fury of combat.
If you've seen this part of the movie, you know
it's like an epic painting that's come to life. But
(31:22):
the point I want to make is that by alternating
between slow and fast, the cinematography continues to violate our predictions,
and so it holds our attention throughout.
Speaker 2 (31:34):
Now.
Speaker 1 (31:35):
One thing I find amazing is that HG. Wells wrote
his passage before there was fast motion video to watch,
so he did this the old fashioned way by imagining
the whole thing. Now, it turns out, if you are
sufficiently imaginative, you could really do an amazing job on this,
even before witnessing it yourself.
Speaker 2 (31:56):
For example, five years before HG.
Speaker 1 (31:59):
Well's machine, the great psychologist William James wrote a book
called Principles of Psychology.
Speaker 2 (32:07):
He has a chapter called the Perception of Time, and.
Speaker 1 (32:10):
In it he writes this strikingly poetic passage.
Speaker 4 (32:15):
We have every reason to think that creatures may possibly
differ enormously in the amounts of duration which they intuitively feel,
and in the fineness of the events that may fill it.
Von Beher has indulged in some interesting computations of the
effect of such differences in changing the aspect of nature.
Suppose we were able, within the length of a second
to note ten thousand events distinctly, instead of barely ten
(32:38):
as now. If our life were then destined to hold
the same number of impressions, it might be one thousand
times as short. We should live less than a month
and personally know nothing of the change of seasons. If
born in winter, we should now believe in summer as
we now believe in the heats of the carboniferous era.
The motions of organic beings would be so slow to
(33:00):
our senses as to be inferred not seen. The sun
would stand still in the sky, the moon be almost
free from change, and so on. But now reverse the
hypothesis and suppose a being to get only one thousandth
part of the sensations that we get in a given time,
and consequently live one thousand times as long. Winters and
(33:22):
summers will be to him like quarters of an hour.
Mushrooms and the swifter growing plants will shoot into being
so rapidly as to appear instantaneous creations. Annual shrubs will
rise and fall from the earth like restlessly boiling water springs.
The motions of animals will be as invisible as are
to us the movements of bullets and cannonballs. The sun
(33:43):
will scour through the sky like a meteor, leaving a
fiery trail behind him, et cetera. That such imaginary cases,
barring the superhuman longevity, may be realized somewhere in the
animal kingdom, it would be rash to deny.
Speaker 1 (33:58):
Now may well have read this passage from William James,
and the descriptions in them are beautiful, so none of
them actually needed to see a Hollywood movie to envision this.
But I do think that it doesn't hurt to grow
up around movie technology so that one becomes very comfortable
(34:18):
in thinking about time in different ways by actually seeing
the experience oneself, by directly learning new ways of perceiving.
I'll give you an example. Some of you in your
fifties or older will remember when your teachers showed eight
millimeter films in school. Now, if you've never seen this,
(34:39):
the way it works is that the film strip is
on a reel, a big circular job, and as the
movie plays, that reel is unwinding and the film is
moving to a second reel, which is collecting the film strip.
So the movie starts off wound up on the first
and ends up wound up around the second reel. But
of course the beginning of the movie is now in
(34:59):
the middle of the second reel, and the end of
the movie is on the outside, so you have to
rewind the whole thing back onto the first reel. So
when you're done watching the movie, you just pull the
lever to set the whole thing in reverse, and you
get to witness the whole movie backwards. People are walking backwards,
bicyclists biking backwards, the train is reversing up the track,
(35:23):
the diner is getting more food on his plate. The
person who slipped on the banana peel now slips upward.
So typically the teacher reverses the film at a much
higher speed, so you see the whole thing running backwards quickly.
But what I remember as a little kid in school
was the delight this process always brought to the whole class. So,
(35:43):
starting many decades ago, everyone got to see what backwards
motion looked like. Now it's hard to prove this with certainty,
but one possibility is that this helped people to think
about things in a new way, to open up this
new time domain of things running backwards. So take the
Swiss physicist Ernst Stuckelberg. In the nineteen forties. He was
(36:07):
chewing on a problem about elementary particles. His colleague Paul
Durak had published a paper that unified a whole bunch
of things in physics, but something came out of Diract's
equation that was unexpected to everyone. The math suggested there
should be a particle like an electron, but with positive
charge instead of negative, and no one had ever seen this,
(36:30):
but here was the math saying it should exist. Eventually,
this came to be called a positron, but no one
knew what could explain the existence of such a particle,
And in nineteen forty one Stuckelberg realized that a positron
and an electron are the same little particle, but a
positron is just an electron traveling backward in time, and
(36:53):
that made all the math work. Now it's impossible to
know the answer, but the question is would Stuckelberg have
had a harder time coming up with this hypothesis if
he had never seen backward motion. Once you've seen a
film strip run, once you've seen time run backward that way,
then that door of possibility is opened up in your
(37:16):
internal model, and once it's open, you can't shut it,
and it's much easier to think about things like it.
This is a specific case of a more general truism
that new technologies allow us to experience things that we
could not have experienced otherwise, and that really opens up
our mental.
Speaker 2 (37:36):
Space to new ideas.
Speaker 1 (37:39):
And I'm very interested in seeing where future technology takes
us because we can nowadays try out experiments in very
simple ways that were impossible last century. For example, my
son plays a VR game called super Hot in which
you're fending off gunmen who are all trying to get you.
But the key is that the speed of motion of
(38:02):
the world depends on the movement of your own body.
So if you stand very still, the world creeps along
in super slow motion. But as soon as you make
a move to lift your gun or move a little bit,
the world speeds up. And if you're moving really fast,
the world around you moves fast as well. It's an
(38:22):
incredible experience to play this, and for the generation of
children growing up, it's just part of the background furniture
that you can play a game where the passage of
time is variable and under your control. But for the
rest of us, this is a whole new dimension of
time to explore. The final thing we'll address today is
(38:45):
why we're not attracted slow motion in an audio only format.
I suggest it's because with words, we're only analyzing for
the meaning. We're just working to capture all the words
so that we can translate that into an understanding of
the message, and in fact we all know from audiobooks
and YouTube videos you can take in words at a
(39:07):
much faster pace than I would be able to naturally
produce them.
Speaker 2 (39:10):
And so there's no benefit in slowing them down.
Speaker 1 (39:14):
So that's why we don't do the speeding and slowing
we see in the movie three hundred. If we were
reading an audio book about the Battle of Thermopylae, like
Leonides swung the broad sword and hit the Persian soldier
under the ribs, and then Leonid stepped over the body
and looked around until he saw his next target horseman
charging him with a.
Speaker 2 (39:35):
Lance, and he spun and ducked the lance. I don't know.
Speaker 1 (39:39):
Maybe we've just invented a new style there, but I
doubt it. So we love to do slow motion with videos,
but not text. But I think there's an interesting realm
in between. Although video is just over a century old,
I think there's a sense in which people have for
millennia figured out how to dance in some way between
(40:00):
slow motion and fast motion. And this is something I
learned from my friend Tony Brandt. We were talking about
these kinds of ideas once and Tony pointed out the
difference in opera between the Aria and the recitative, and
Aria spends several minutes on a single idea, like the
love of the protagonists for the Beautiful Maiden. It's all
(40:23):
about deep emotions and reflections, and it pauses the plot
to focus on the character's inner feelings.
Speaker 2 (40:31):
But the restititive is the opposite.
Speaker 1 (40:35):
First of all, it's speech like, there's no rhythm, maybe
just a harpsichord plays along, and the only job of
the recitative is to crank the plot along. It just
tells you about some big passage of time. So Arias
explore something simple in great depth. The recititive moves the
(40:55):
story forward. So Arias might be considered perhaps the medieval
version of slow Moe in the cinema, really zooming in
on the moment, while the restitative is the fast motion
speeding up of the plot. Okay, so I've told you
that we don't do fast and slow motion when there's
only audio involved, and there's a sense in which we
(41:18):
grasp at this speeding or slowing with opera. But it's
different with visual scenes because here we're not just trying
to decrypt a message, but instead we're watching the incredibly
high bandwidth visual world and we're making predictions about the
physics and getting feedback from what we're seeing. And if
(41:40):
my hypothesis is correct, we're calibrating our own internal clocks
to the world of.
Speaker 2 (41:46):
What we see.
Speaker 1 (41:48):
And that's why fast and slow motion, although they are
relatively recent additions to the canon of cinema, this is
why they grab our attention and are.
Speaker 2 (41:59):
Here to day.
Speaker 1 (42:00):
So let's wrap up beyond its esthetic and emotional appeal,
slow motion serves a critical narrative function in filmmaking. By
manipulating time, directors can emphasize key moments, They can reveal
hidden details. They can grab your attention by violating your
brain's expectations. Slow motion is more than just a visual trick.
(42:25):
It's a way of stretching moments, suspending us in the
gravity of an emotion or a decision, or a final
breath before impact. It allows us to live inside the
flicker of an instant, to taste the weight of time.
Perhaps this is why our brains are so captivated by it,
(42:49):
because in life, time generally moves at one relentless speed,
but in film, we can linger in a moment. We
can turns into minutes. We can reveal the invisible in
the visible slow motion reminds us that buried in every blink,
(43:10):
every heartbeat, every fleeting instant, there is a world of
depth waiting to be discovered. Go to Eagleman dot com
slash podcast for more information and to find further reading.
Speaker 2 (43:27):
Send me an email at.
Speaker 1 (43:28):
Podcasts at eagleman dot com with questions or discussion, and
check out and subscribe to Inner Cosmos on YouTube for
videos of each episode and to leave comments until next time.
I'm David Eagleman and this is the one hundredth episode
of Inner Cosmos.
Why do we love to watch slow motion in the movies?
What do Bonnie and Clyde or Inception or the Matrix
tell us about brains and time perception? And what does
any of this have to do with unmasking hidden data
or champion bicyclists or elementary particles or murderers or HG
(00:26):
Well's time machine. Welcome to Intercosmos with me David Eagleman.
I'm a neuroscientist and an author at Stanford and in
these episodes we dive deeply into our three pound universe
to understand some of the most surprising aspects of our lives.
(00:54):
Today's episode is about slow motion and what's going on
in the brain and why we are attracted to it.
So we all know that if you go to any
random blockbuster, you're really likely to see some of the
sequences in slow motions gets employed to accentuate the choreography
of gun battles or sword fights, and of course it
(01:17):
doesn't even have to be fighting. You might see it
in a shot of a basketball dunk, or a flipping car,
or sprinters crossing the finish line, whatever the shot. What
we get to witness is fluidity and elegance in a
visually captivating spectacle that has become a hallmark of Hollywood,
(01:40):
and it goes even beyond action movies. Even in dramas
and romances. We see slow motion get leveraged to capture
intimate emotional moments. We savor the subtleties of someone's eye
movements or facial expressions or body movements. We understand something
about the unspoken longing and restrained passion between two protagonists,
(02:05):
or we watch a tear fall, or we see the
moment that someone has an unexpected revelation.
Speaker 2 (02:13):
So we see slow motion all the time.
Speaker 1 (02:15):
But have you ever wondered from a neuroscience perspective what
that's all about and why brains love it so much? Yeah,
me too, and hence today's podcast. So let's start by
zooming way out. When did slow motion really start in movies?
You may be surprised to know that the era of
(02:36):
slow mo didn't really begin until nineteen sixty seven. And
what stuns me about this is that by nineteen sixty
seven we already had supersonic flight and bionic limbs and
credit cards and digital music, and the space race was
in full swing, but nobody was using slow motion until.
Speaker 3 (02:59):
I thought, I have an idea about the end that
should be like a spastic ballet, and that was the image.
Speaker 1 (03:09):
That's Arthur Penn, the director of the nineteen sixty seven
film Bonnie and Clyde. This was a big Hollywood blockbuster
that dramatized the real life crime spree of Bonnie Parker
and Clyde Barrow, and the stars were Fade, Done Away
and Warren Batty. So Bonnie and Clyde were a young
couple who became bank robbers during the Great Depression, and
(03:32):
in the movie, they travel across the country with their
growing gang and their crimes escalate, and this attracts the
relentless pursuit by law enforcement, which culminates in a violent ambush.
Speaker 3 (03:47):
And then so I came to the technicians and I said, look,
this is what I want to get.
Speaker 2 (03:52):
They said, you can't do that.
Speaker 3 (03:54):
I said, I want four cameras. I want them running
at different speeds, I want them ganged together, and I
want to roll them all at the same time.
Speaker 1 (04:07):
And so that's what happened. In the final scene, the
cinematography decelerates into a balletic slow motion as Bonnie and
Clyde meet their bloody end. Under a hailstorm of police bullets,
so as they experience their final moment, the audience is
(04:28):
given some extra seconds to be witnessed to it. Now,
this really shocked a lot of people. Critics called Arthur
Penn's slowed down death scene gratuitous and callous, but.
Speaker 2 (04:44):
The idea caught on.
Speaker 1 (04:46):
Bonnie and Clyde had opened the door to slow motion
and it's never been shut since.
Speaker 2 (04:52):
Now.
Speaker 1 (04:52):
By the way, it's not that the technology was new.
The method for slow motion movies came into being in
nineteen o five four when the Austrian physicist August Musker
invented the technique. So what's the technique. You just speed
up the recording camera so you're capturing more frames per second.
(05:12):
In this way, what you're doing is capturing faster changes.
The time in between each picture is shorter than normal.
So then when you play the film strip back at
regular speed, like twenty four frames per second, then the
scene appears to be in slow motion because the change
(05:32):
from one frame to the next is very small. This
was initially just getting used for scientific purposes to slow
down processes that you can't see well with the naked eye,
but eventually slow motion was adopted by filmmakers to enhance
visual storytelling. Now, before we go on, I want to
make sure we have a clear distinction between slow motion
(05:55):
in movies and the impression that you might have if
you have experienced a life threatening situation and it feels
like the event took a long time. Is this because
the frame rate of your brain changes.
Speaker 3 (06:11):
No.
Speaker 1 (06:12):
Ninety nine episodes ago, I talked about the impression we
have of very frightening events having taken a long time.
This is something I first experienced as a child when
I fell off of a roof. I have very clear memories,
and it feels like the whole thing took a few seconds,
even though I can calculate that it only took point
(06:32):
six seconds to get from the top to the bottom. Now,
it turns out that this observation about scary events seeming
to last longer. This is at least one hundred years
old in the scientific literature, although I imagine that people have
noticed this from time immemorial. But my laboratory was the
first to run experiments on it to see if it
was an issue of a faster perceptual frame rate, which
(06:57):
again is how a movie camera captured slow motion or instead,
does it happen to us? Because of the laying down
of denser memories and the retrospective estimate of how much
time had passed. We ran experiments by presenting information at
a faster rate than a person could normally see, and
(07:20):
then we put them in a very scary situation where
we dropped them from one hundred and fifty foot tall
tower and they were caught in a net below. If
a person is like a camera speeding up its frame rate,
then they would be able to easily see the information
we were flashing at them. But our results indicated that
the slow motion effect was a.
Speaker 2 (07:42):
Trick of memory.
Speaker 1 (07:43):
In other words, when you're in fear for your life,
your brain writes down dense memory. It's capturing everything it can,
whereas normally your memory is very leaky. So when your
brain then asks what just happened? What just happened and
reads it out all those dense memories, it estimates that
the event must have taken longer. Your brain has all
(08:08):
these rich memories, let's say, the hood crumpling and the
rear view mirror falling off, and the expression on the
other driver's face and so on, And given that opulence
of memory, your brain calculates that the whole event must
have represented a slightly longer duration. In other words, what
happens during a scary event is a totally different mechanism
(08:32):
than slow motion video. Now, when I published our findings,
some people said to me, Hey, I don't think your
conclusion is correct because I had a life threatening car
accident and I know what I experienced. So I said
to them, Okay, but the guy in your passenger seat
who was yelling watch out, did it actually.
Speaker 2 (08:51):
Sound like he was saying.
Speaker 1 (08:57):
Because if not, that means that time is not actually dilated.
Because if you are recording something with a faster frame rate,
then when you play it back out, everything is stretched.
So with your experience of time dilation, it's not an
issue a faster frame rate like a movie camera, but
(09:17):
instead of denser memory. Please listen to episode one of
this podcast for much more about that. And the reason
I'm telling you about this now is because we're going
to return to this in a few minutes. For now,
let's get back to filmmaking, where the mechanism is very straightforward.
You just take more frames per second. Now, I said
(09:39):
that Bonnie and Clyde was the first major movie to
use slow motion, but there were actually experiments with it
before that. One of the earliest uses in cinema was
in an epic silent film called Intolerance in nineteen sixteen.
This was made by a director named D. W. Griffith,
who was experimenting with all millions of techniques of filmmaking
(10:02):
and used slow motion just a little bit to accentuate
dramatic moments and heighten emotional tension. But two World Wars
that over half a century passed before I was used
in Bonnie and Clyde, in part because the technology had
to advance to make slow motion more accessible and versatile.
By the nineteen sixties, people were building high speed cameras
(10:25):
which were capable of capturing hundreds of frames per second
and eventually thousands, and this is what allowed filmmakers to
push new boundaries of representing time and creating effects that
audiences were captivated by. And the nineteen sixty nine film
The Wild Bunch, two years after Bonnie and Clyde, really
(10:46):
helped popularize the technique. And now, of course we don't
even think about it much because it's a staple of
modern filmmaking. For example, I recently watched a movie called Wanted,
which uses super slow motion every time there's a gun battle.
Where you may remember Christopher Nolan's movie Inception, which has
these beautiful slow motion dream sequences, especially in the kick
(11:11):
moments where they're transitioning from one reality to another. So
increasingly since nineteen sixty seven, movies use time warping all
the time, and the success of this approach has overtaken
commercials and music videos, and it's a standard tool on
our cell phones. And in fact, you can tell when
something has become a staple because then it shifts into
(11:33):
the focus of the comedians. Some years ago, the comedian
Dave Chappelle did a skit in which he was proving
that everything quote looks cooler in slow motion. So in
the skit, he walks into the laundromat and says hello
to a kindly middle aged woman who is preparing her laundry,
and she takes off her sweatshirt so she can add
(11:54):
it to her hamper, and it's all very innocent and laundromaty,
and then he says, let's replay this video in slow motion,
and now everything changes from mundane to sexy in the
slow motion replay. The woman lifts the sweatshirt over her
head and is suddenly replaced by a beautiful young model
(12:14):
who tosses her hair in a vigorous breeze, and she
and Dave Chappelle start dancing around each other as the
wind blows. So this skit cracked up the audience. But
this just underscores our question, what is the appeal of
slow motion? Why do we find it so attractive? I
propose four reasons. The first is the increased esthetic appeal.
(12:40):
When you decelerate time, you can experience so many more
details of this scene. And just like Dave Chappelle noticed,
even ordinary moments get turned into extraordinary visual spectacles. And
this is because by slowing down time, you highlight the
intricate features of a scene. The human eye is naturally
(13:01):
attracted to detail, and slow motion allows us to appreciate
the subtle nuances of a character's movement, or the play
of light and shadow, or birds exploding out of a tree,
or the look on someone's face as they turned to
see that their lover has left. So you remember the
(13:22):
Matrix which came out in ninety nine, and you certainly
remember this bullet dodging scene where Neo bends backward to
avoid a series of bullets fired at him, and this beautiful,
slow sweeping shot captures the fluidity in the wondrous precision
of his movements. The scene could never have worked at
(13:44):
normal speed because the key was how he was making
a move that was not normally physically possible, and the
otherworldly nature of this required immersing us to have time
to really take it in. Just like Bonnie and Clyde,
the slowness heightens the tension and the drama. We the
(14:05):
audience get to squeeze every moment out of the scene
rather than have it zip by.
Speaker 2 (14:12):
While we're reaching for our popcorn. And again, it doesn't
have to be action scenes.
Speaker 1 (14:16):
Look at Terrence Malick's film The Tree of Life or
Darren Aronofsky's Requiem for a Dream. The slow motion allows
viewers to fully absorb the emotional weight of a scene. Okay,
(14:48):
so increasing the aesthetic appeal, that's the obvious reason, But
from a neuroscience point of view, I'm going to suggest
there are deeper reasons why slow motion works. And this
leads to my suggestion two, which is that slow motion
film serves as a proxy for denser memories. So a
(15:08):
few moments ago, I told you what happens during a
life threatening situation. Although you don't actually see the event
unfold in slow motion, the denser memories that you have
make it seem like it must have been that way
in retrospect, because there's a greater than normal amount of
detail when the memory is read back out. And I
(15:30):
suggest that slow motion film is a stand in a
substitute for this extra dense memory. By watching a movie
scene slowly, we get to enjoy a rich experience with
plenty of time to dwell on all the details that
would normally streak right past us. We have the opportunity
(15:52):
to attend to the details and commit them to memory,
just like we have after a real life high adrenaline moment.
In other words, slow motion film recreates the sensation of
grasping all the details, and this explains the natural partnership
of slow motion videography.
Speaker 2 (16:13):
With high adrenaline moments.
Speaker 1 (16:15):
It's no accident that the first time it really got
used was the ambush death scene of Bonnie and Clyde.
The director Arthur Penn said in an interview quote the
intention there was to get this attenuation of time that
one experience is when you see something like a terrible
automobile accident end quote. And giving the audience a heightened
(16:38):
ability to catch and remember details worked well, and it's
become a standard signature of high stakes moments. Arthur Penn
went on to say in nineteen eighty nine, quote, God
knows we've been imitated thousands and thousands of times.
Speaker 2 (16:54):
Now.
Speaker 1 (16:55):
Every time you see someone attempting violence, they go into
that basics slow motion end quote. So my assertion is
that when we witness a moment unfold bit by bit
in the movies, we get to appreciate its import as
though we were experiencing the high adrenaline moment ourselves. But
(17:17):
not all interesting slow motion video involves high adrenaline situations,
So there is more to our love of it. And
this leads us to my third suggestion for the success
of slow motion, which is that it extends human perception
by unmasking hidden data. It allows the revelation of data
(17:38):
that's hidden in the folds of time, just like a
microscope allows us to appreciate the details of a fly's wing.
And I'm not just talking about action sequences here or
neo's unusual movements in the matrix, there's much more that
can be unmasked. Consider something like microexpressions. These are fast
(17:59):
movements of facial muscles that pass rapidly and unconsciously over
people's faces. Now, everyone's face does this naturally all the time,
but you can't really see someone else's micro expressions because
they're too brief. You're not aware that you are making
micro expressions, and someone watching you isn't consciously aware that
(18:20):
you did it. But it turns out that micro expressions
can carry information and can reveal secrets, including things like deception.
For example, you may remember the story of Susan Smith,
who claimed that her children had been kidnapped in a carjacking,
when in fact she had drowned them. For several days,
(18:41):
she was on the TV news pleading for help in
finding her children, but some colleagues of mine claimed that
a slowed down version of the video revealed micro expressions
that suggested she was lying about the whole event. The
idea is that slow motion video unmasks the world of
(19:01):
these temporally hidden facial clues, and by unveiling things that
are undetectable by consciousness, slow motion can allow not just
temporal sleuthing but temporal intimacy. Consider this passage by the
British sports writer Matt Rendell about the Tour de France
winner Marco Pantani. Writing about the use of super slow
(19:26):
motion cameras in sport, Rendell wrote, what I think is
one of the most beautiful passages in sports writing. Here
it is read by the actor Sean Judge.
Speaker 4 (19:36):
Now, as he arrives towards victory and the Giro Dtalia,
the camera almost caresses him. The five seconds between the
moment Marco appeared in the closing strait and the moment
he crossed the finish line are extruded to fifteen and
during seconds ba image frames his head and little else,
(19:58):
revealing details in visible in real time and at standard resolution.
A drop of sweat that falls from his chin as
he makes the bend, the gaping jaw and crumpled forehead,
and lines beneath the eyes that deepen as Marco rings
still more speed from the mountain. Then, and it must
(20:22):
be the moment he crosses the line. He begins to
rise out of his agony. The torso rises to vertical,
the arms spread out into a crucifix position, the eyelids
descend and Marco's face lifts towards the sky. It is
a moment of transfiguration visible only in super SlowMo or
(20:46):
in still and only the best of the finish line
photographers catch it. Super SloMo shows us something we could
never otherwise see, involuntary gesture Marco never chose to reveal,
perhaps because without super slow MOO technology he cannot know
(21:07):
he makes them. The public knows more about Marco than
Marco himself, a truth we are tempted to imagine, and
one that has nothing to do with the race outcome
as such, for the pictures frame out the finish line
in the clock and show nothing of his work rate,
muscular toil, or the relative positions of the riders that
(21:30):
yield the race result. Instead, we find ourselves looking into
Marco's face the way a mother and her baby might,
or lovers at the moment their affection is first reciprocated.
Speaker 1 (21:46):
So slow motion allows us to pick up on the
world that would otherwise rush past us. And in this
slow world we get to luxuriate in the otherwise invisible
detail with which we're always surrounded but we never see.
And now we're ready from a fourth point. Slow motion
(22:08):
video holds our attention by violating expectations. So during a
lifetime of experience, your brain develops deeply wired expectations about
Newtonian physics. So when a ball gets thrown to you,
your brain unconsciously uses these internal models to predict where
(22:29):
and when it's going to go, and you move your
body in your hand to the right spot. These models
are so ingrained into our nervous systems that if you
lob a ball to an astronaut floating in zero G,
she will move her hand to the wrong spot. She'll
move to catch it as though she's in a normal
one G environment. So part of the high level of
(22:52):
engagement during slow motion comes from a violation of these
expectations about physics. Imagine you're watching the matrix and you
observe Trinity leap into the air to kick an agent.
Your brain makes unconscious predictions about exactly when she's going
to come back down. But to your brain's surprise, time
(23:17):
slows down and Trinity hangs in the air longer than expected.
Your expectations about when she's going to hit the ground
have been violated, and this draws us in. Our brains
zoom in on this because attention is maximally attracted to
whatever we predict incorrectly. Conversely, when everything goes according to plan,
(23:40):
we don't pay any attention at all. We are fond
of slow motion video because it engages our attention. We
constantly get the temporal predictions wrong, and so we are
perpetually on alert. In fact, I did a very surprising
experiment on this some years ago. I started with this
hypoc prothesis that your internal model is always calibrating itself,
(24:04):
keeping itself tuned up by comparing against the physics of
the real world. So if it's running too slowly, it
watches the ball hit the ground and realizes that its
prediction was just slightly behind, so it speeds up its expectations.
And the same if it watches the ball and it
realizes that its prediction was just slightly ahead, then it
(24:26):
slows itself down. So it uses the outside world as
the ground truth to keep itself nicely calibrated. Now you
might think, how would you ever prove a hypothesis like that, Well,
here's how I had people compare the durations of two
brief flashes on the screen. So on the screen you
(24:48):
see a little circle that goes flash and then a
moment later, another little circle that goes flash. And on
every trial, I'm slightly tweaking the duration so that one
is slightly longer than the other, and you just say
which was longer than which? Okay, now here's the trick.
I have people watch a video, for example, a camera
(25:08):
that follows the cheetah sprinting across the serengetti. Now, if
I just superimpose one flash and then the second flash
on top of the video, you have no trouble saying
which one was longer than which. But now I do
something special. At some point in the video, it suddenly
goes into slow motion. Then you might know that when
(25:29):
cheetahs run, all four of their legs come off the ground.
Speaker 2 (25:33):
So now you're seeing this sleek.
Speaker 1 (25:35):
Animal floating in the air and you're waiting for his
front pause to hit the ground. But now that we're
suddenly in slow motion, your time prediction is off. You
expected his legs to hit the ground, but they haven't yet.
Speaker 2 (25:50):
And because we evolved.
Speaker 1 (25:51):
In a world with no such thing as slow motion,
your brain's only choice is to assume that the mistake
is its own, and it compensates by slowing down its expectation. Now,
how do I know the brain does this. It's because
I can see how you judge the duration of a flash.
(26:11):
During the sudden slow motion, the flash now appears to
last a shorter time, about twenty seven percent shorter.
Speaker 2 (26:20):
Why.
Speaker 1 (26:22):
Roughly speaking, it's because your brain is forced to slightly
tweak its estimate of the pace of time during the
slow motion bit. Think of it like a clock ticking
more slowly, and now the flash covers fewer ticks, and.
Speaker 2 (26:38):
So it is judged to last less time.
Speaker 1 (26:42):
I did various control versions of this experiment in which
I shuffled the frames, or I shuffled all the pixels,
or I ran the whole thing upside down, and in
all these cases there was no distortion of the apparent
duration of the flashes. It only happened when the future
position of objects was predictable by physics. So let me
(27:04):
just summarize this. When your brain is watching any scene,
it's making predictions about where things will be, and if
the scene suddenly changes speed, then your internal model will
predict incorrectly. But I suggest the nervous system can eliminate
these feedback prediction errors with a simple trick by modifying
(27:27):
its estimated speed of the flow of physical time.
Speaker 2 (27:32):
It's a very subtle.
Speaker 1 (27:33):
Change, but it has measurable perceptual consequences which are exposed
by this novel time distortion illusion. Okay, that was a
little technical, but it's one of my favorite experiments. Now,
we've been talking all about slow motion, but on the
flip side of slow motion, there is a world unmasked
(27:53):
by fast motion. Think about quickly blossoming flowers, or imagine
the the arterial traffic patterns of cities, or watched the
laminar rush of clouds across the sky, or observe the
way that the sun drops like a ball behind the
mountain and the world dims as though by.
Speaker 2 (28:14):
A dimmer switch.
Speaker 1 (28:16):
So fast motion reveals secrets not so much in the
domain of human facial expressions, but instead in the dance
of the very large. So let's take a look at
(28:43):
the kind of descriptions you can generate when speeding up
the world. In eighteen ninety five, HG. Wells published The
Time Machine. He did this as a serial novel in
a magazine. It's one of the earliest and most influential
works of science fiction, in part because it introduced this
concept of a time travel device, which became a staple
(29:05):
in the genre. But it's beautifully written, and we can
see the imagination of fast time when the unnamed time
traveler builds this device and travels to the very distant
future of the year eight hundred and two, thy seven
hundred and one. Here's the part I want to share
with you, when he cranks the lever down on the
(29:27):
machine and gets going. This passage is read again by
actor Sean Judge.
Speaker 4 (29:33):
As I put on pace, night followed day like the
flapping of a black wing. I saw the sun hopping
swiftly across the sky, leaping it every minute, and every minute,
marking a day. The slowest snail that ever crawled dashed by,
too fast for me. Presently, as I went on, still
gaining velocity, the palpitation of day and night merged into
(29:53):
one continuous grayness. The jerking sun became a streak of fire,
the moon a fa interfluctuating band. I saw trees growing
and changing like puffs of vapor. Huge buildings rise up,
faint and fair, and pass like dreams. The whole surface
of the earth seemed changed, melting and flowing under my eyes.
Speaker 1 (30:16):
So in the same way, that slow motion allows us
to see details that we would not otherwise catch. Fast
motion plays that same game. It's no surprise, then, that
a very engaging style of cinematography is to rapidly alternate
between speeding and slowing. Think of the battle scenes in
(30:37):
the movie three hundred. As the Spartans charge, the camera
captures their ferocity in real time, the thunder of their
shields clashing and the spears piercing, And then suddenly the
world slows and every movement stretches into a balletic display
of destructions. Sweat glistens, blood arcs gracefully through the air
(31:00):
like crimson silk. The slow motion lingers on every ripple
of flash, every grimace of pain, before snapping back to
faster than normal speed. You see this explosion of chaos
and bodies tumbling and dust swirling under the fury of combat.
If you've seen this part of the movie, you know
it's like an epic painting that's come to life. But
(31:22):
the point I want to make is that by alternating
between slow and fast, the cinematography continues to violate our predictions,
and so it holds our attention throughout.
Speaker 2 (31:34):
Now.
Speaker 1 (31:35):
One thing I find amazing is that HG. Wells wrote
his passage before there was fast motion video to watch,
so he did this the old fashioned way by imagining
the whole thing. Now, it turns out, if you are
sufficiently imaginative, you could really do an amazing job on this,
even before witnessing it yourself.
Speaker 2 (31:56):
For example, five years before HG.
Speaker 1 (31:59):
Well's machine, the great psychologist William James wrote a book
called Principles of Psychology.
Speaker 2 (32:07):
He has a chapter called the Perception of Time, and.
Speaker 1 (32:10):
In it he writes this strikingly poetic passage.
Speaker 4 (32:15):
We have every reason to think that creatures may possibly
differ enormously in the amounts of duration which they intuitively feel,
and in the fineness of the events that may fill it.
Von Beher has indulged in some interesting computations of the
effect of such differences in changing the aspect of nature.
Suppose we were able, within the length of a second
to note ten thousand events distinctly, instead of barely ten
(32:38):
as now. If our life were then destined to hold
the same number of impressions, it might be one thousand
times as short. We should live less than a month
and personally know nothing of the change of seasons. If
born in winter, we should now believe in summer as
we now believe in the heats of the carboniferous era.
The motions of organic beings would be so slow to
(33:00):
our senses as to be inferred not seen. The sun
would stand still in the sky, the moon be almost
free from change, and so on. But now reverse the
hypothesis and suppose a being to get only one thousandth
part of the sensations that we get in a given time,
and consequently live one thousand times as long. Winters and
(33:22):
summers will be to him like quarters of an hour.
Mushrooms and the swifter growing plants will shoot into being
so rapidly as to appear instantaneous creations. Annual shrubs will
rise and fall from the earth like restlessly boiling water springs.
The motions of animals will be as invisible as are
to us the movements of bullets and cannonballs. The sun
(33:43):
will scour through the sky like a meteor, leaving a
fiery trail behind him, et cetera. That such imaginary cases,
barring the superhuman longevity, may be realized somewhere in the
animal kingdom, it would be rash to deny.
Speaker 1 (33:58):
Now may well have read this passage from William James,
and the descriptions in them are beautiful, so none of
them actually needed to see a Hollywood movie to envision this.
But I do think that it doesn't hurt to grow
up around movie technology so that one becomes very comfortable
(34:18):
in thinking about time in different ways by actually seeing
the experience oneself, by directly learning new ways of perceiving.
I'll give you an example. Some of you in your
fifties or older will remember when your teachers showed eight
millimeter films in school. Now, if you've never seen this,
(34:39):
the way it works is that the film strip is
on a reel, a big circular job, and as the
movie plays, that reel is unwinding and the film is
moving to a second reel, which is collecting the film strip.
So the movie starts off wound up on the first
and ends up wound up around the second reel. But
of course the beginning of the movie is now in
(34:59):
the middle of the second reel, and the end of
the movie is on the outside, so you have to
rewind the whole thing back onto the first reel. So
when you're done watching the movie, you just pull the
lever to set the whole thing in reverse, and you
get to witness the whole movie backwards. People are walking backwards,
bicyclists biking backwards, the train is reversing up the track,
(35:23):
the diner is getting more food on his plate. The
person who slipped on the banana peel now slips upward.
So typically the teacher reverses the film at a much
higher speed, so you see the whole thing running backwards quickly.
But what I remember as a little kid in school
was the delight this process always brought to the whole class. So,
(35:43):
starting many decades ago, everyone got to see what backwards
motion looked like. Now it's hard to prove this with certainty,
but one possibility is that this helped people to think
about things in a new way, to open up this
new time domain of things running backwards. So take the
Swiss physicist Ernst Stuckelberg. In the nineteen forties. He was
(36:07):
chewing on a problem about elementary particles. His colleague Paul
Durak had published a paper that unified a whole bunch
of things in physics, but something came out of Diract's
equation that was unexpected to everyone. The math suggested there
should be a particle like an electron, but with positive
charge instead of negative, and no one had ever seen this,
(36:30):
but here was the math saying it should exist. Eventually,
this came to be called a positron, but no one
knew what could explain the existence of such a particle,
And in nineteen forty one Stuckelberg realized that a positron
and an electron are the same little particle, but a
positron is just an electron traveling backward in time, and
(36:53):
that made all the math work. Now it's impossible to
know the answer, but the question is would Stuckelberg have
had a harder time coming up with this hypothesis if
he had never seen backward motion. Once you've seen a
film strip run, once you've seen time run backward that way,
then that door of possibility is opened up in your
(37:16):
internal model, and once it's open, you can't shut it,
and it's much easier to think about things like it.
This is a specific case of a more general truism
that new technologies allow us to experience things that we
could not have experienced otherwise, and that really opens up
our mental.
Speaker 2 (37:36):
Space to new ideas.
Speaker 1 (37:39):
And I'm very interested in seeing where future technology takes
us because we can nowadays try out experiments in very
simple ways that were impossible last century. For example, my
son plays a VR game called super Hot in which
you're fending off gunmen who are all trying to get you.
But the key is that the speed of motion of
(38:02):
the world depends on the movement of your own body.
So if you stand very still, the world creeps along
in super slow motion. But as soon as you make
a move to lift your gun or move a little bit,
the world speeds up. And if you're moving really fast,
the world around you moves fast as well. It's an
(38:22):
incredible experience to play this, and for the generation of
children growing up, it's just part of the background furniture
that you can play a game where the passage of
time is variable and under your control. But for the
rest of us, this is a whole new dimension of
time to explore. The final thing we'll address today is
(38:45):
why we're not attracted slow motion in an audio only format.
I suggest it's because with words, we're only analyzing for
the meaning. We're just working to capture all the words
so that we can translate that into an understanding of
the message, and in fact we all know from audiobooks
and YouTube videos you can take in words at a
(39:07):
much faster pace than I would be able to naturally
produce them.
Speaker 2 (39:10):
And so there's no benefit in slowing them down.
Speaker 1 (39:14):
So that's why we don't do the speeding and slowing
we see in the movie three hundred. If we were
reading an audio book about the Battle of Thermopylae, like
Leonides swung the broad sword and hit the Persian soldier
under the ribs, and then Leonid stepped over the body
and looked around until he saw his next target horseman
charging him with a.
Speaker 2 (39:35):
Lance, and he spun and ducked the lance. I don't know.
Speaker 1 (39:39):
Maybe we've just invented a new style there, but I
doubt it. So we love to do slow motion with videos,
but not text. But I think there's an interesting realm
in between. Although video is just over a century old,
I think there's a sense in which people have for
millennia figured out how to dance in some way between
(40:00):
slow motion and fast motion. And this is something I
learned from my friend Tony Brandt. We were talking about
these kinds of ideas once and Tony pointed out the
difference in opera between the Aria and the recitative, and
Aria spends several minutes on a single idea, like the
love of the protagonists for the Beautiful Maiden. It's all
(40:23):
about deep emotions and reflections, and it pauses the plot
to focus on the character's inner feelings.
Speaker 2 (40:31):
But the restititive is the opposite.
Speaker 1 (40:35):
First of all, it's speech like, there's no rhythm, maybe
just a harpsichord plays along, and the only job of
the recitative is to crank the plot along. It just
tells you about some big passage of time. So Arias
explore something simple in great depth. The recititive moves the
(40:55):
story forward. So Arias might be considered perhaps the medieval
version of slow Moe in the cinema, really zooming in
on the moment, while the restitative is the fast motion
speeding up of the plot. Okay, so I've told you
that we don't do fast and slow motion when there's
only audio involved, and there's a sense in which we
(41:18):
grasp at this speeding or slowing with opera. But it's
different with visual scenes because here we're not just trying
to decrypt a message, but instead we're watching the incredibly
high bandwidth visual world and we're making predictions about the
physics and getting feedback from what we're seeing. And if
(41:40):
my hypothesis is correct, we're calibrating our own internal clocks
to the world of.
Speaker 2 (41:46):
What we see.
Speaker 1 (41:48):
And that's why fast and slow motion, although they are
relatively recent additions to the canon of cinema, this is
why they grab our attention and are.
Speaker 2 (41:59):
Here to day.
Speaker 1 (42:00):
So let's wrap up beyond its esthetic and emotional appeal,
slow motion serves a critical narrative function in filmmaking. By
manipulating time, directors can emphasize key moments, They can reveal
hidden details. They can grab your attention by violating your
brain's expectations. Slow motion is more than just a visual trick.
(42:25):
It's a way of stretching moments, suspending us in the
gravity of an emotion or a decision, or a final
breath before impact. It allows us to live inside the
flicker of an instant, to taste the weight of time.
Perhaps this is why our brains are so captivated by it,
(42:49):
because in life, time generally moves at one relentless speed,
but in film, we can linger in a moment. We
can turns into minutes. We can reveal the invisible in
the visible slow motion reminds us that buried in every blink,
(43:10):
every heartbeat, every fleeting instant, there is a world of
depth waiting to be discovered. Go to Eagleman dot com
slash podcast for more information and to find further reading.
Speaker 2 (43:27):
Send me an email at.
Speaker 1 (43:28):
Podcasts at eagleman dot com with questions or discussion, and
check out and subscribe to Inner Cosmos on YouTube for
videos of each episode and to leave comments until next time.
I'm David Eagleman and this is the one hundredth episode
of Inner Cosmos.
Host
David Eagleman
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