February 21, 2009

Why do we love slow motion video?

David Eagleman is guest blogging this week.

During my studies of human time perception I’ve become fascinated by a peripheral question: why do we love slow-motion photography so much? Movies like The Matrix and 300 use time warping as a standard tool in their cinematographic toolbox. The success of this approach has leaked into commercials and music videos and almost every other action film on the scene. Even comedian Dave Chappelle has noted our love of slow-mo: to demonstrate that everything “looks cooler in slow motion,” he shows how his experience in the laundromat changes from mundane to sexy as soon as it is replayed slowly (in slow motion, the old woman by the washing machine becomes a young model tossing her locks of hair in the breeze).

So why is time warping so successful and engaging? I propose three reasons.

1: More time gives a proxy for denser memories

I recently posted about the claim that time slows during a life-threatening event. To the best that we were able to address this, our studies suggested that the impression of slowed time is a trick of memory: denser memories are laid down during salient events, yielding more than the normal amount of detail when read back out. So one can speculate that slow motion video gives a proxy for this extra-dense memory: by presenting a scene slowly, one can enjoy a rich experience with plenty of time to dwell on all the details that normally leak away from us. In other words, when a movie scene is presented slowly we can grab onto and remember many details, just as we do during a real-life high-adrenaline moment.

This idea can explain the natural introduction of slow motion videography into scenes of violence. The first American movie to use slow motion was Bonnie and Clyde. Much to the shock of the audience, the cinematography went into balletic slow motion as the two main characters of the movie met their violent end under a hailstorm of bullets from the police. As Bonnie and Clyde lived out their final seconds, the audience got several extra seconds in which to appreciate it. The director, Arthur Penn, had an intuition about what he was doing; he reported: "The intention there was to get this...attenuation of time that one experiences when you see something, like a terrible automobile accident." Although critics at the time called the slowing of the death scene gratuitous and callous, the idea caught on. Giving the audience a heightened ability to catch and remember details worked well and has been imitated thousands of times since.

But note that not all interesting slow-mo videography involves high-adrenaline situations, indicating that there may be more to it--and this leads us to the next point.

2: Slow motion extends human perception by unmasking hidden data

From a transhumanist perspective, slow motion videography is a technology that allows us to extend our senses beyond their natural capacities. It allows the revelation of data hidden in the folds of time, just as a microscope allows us to appreciate the wonders of a fly's wing or a microbe's choreography.

As one example, consider microexpressions, the fast movement of facial muscles that pass rapidly and unconsciously over peoples’ faces. Microexpressions are normally not accessible to awareness (the owner’s or the viewer’s) because they are too brief. But they can reveal all sorts of secrets, including when someone is lying. For example, when Susan Smith got on the TV news to plead for help in finding her kidnapped children, a slowed-down version revealed micro-expressions that could suggest (at least, with the benefit of hindsight) that she was lying about the whole event. Slow motion video unmasks the world of these temporally hidden facial clues.

Moreover, by unveiling things 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 1998 Tour de France winner Marco Pantani. Writing about the use of super slow-motion cameras in sport, Rendell penned what I consider to be one of the most beautiful passages in sports writing:
Now, as he rides towards victory in the Giro d’Italia, the camera almost caresses him. The five seconds between the moment Marco appeared in the closing straight and the moment he crossed the finish line are extruded to fifteen enduring seconds. The image frames his head and little else, revealing details invisible 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 wrings still more speed from the mountain. Then – and it must 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 slo-mo or in still – and only the best of the finish-line photographers catch it. Super slo-mo shows us something we could never otherwise see – involuntary gestures Marco never chose to reveal, perhaps because, without super slo-mo technology, he cannot know 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 and the clock, and show nothing of his work rate, muscular toil or the relative positions of the riders that 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.

3: Time-warped video holds our attention by violating expectations

Finally, note that brains develop deeply-wired expectations about Newtonian physics. For example, when a ball gets thrown in the air, your brain unconsciously uses its internal models to predict where and when is it going to hit. These models are so ingrained into our nervous systems that if you lob a tennis ball to an astronaut in zero-g, he will still move his hand to catch it as though he’s in a normal 1-g environment.

I suspect that the high level of engagement during slow-mo video is related to a violation of these expectations about physics. Imagine you are watching The Matrix, and Trinity leaps into the air to kick an agent. Your brain makes (unconscious) predictions about exactly when she’s going to come back down. But, shockingly, time slows down and Trinity hangs in the air longer than expected. Your expectations about when she will land have been violated.

As for why we find this interesting, it is probably because these violations hold our attention. Attention is maximally engaged when predictions are violated (an old idea that Jeff Hawkins summarizes nicely in his book On Intelligence). So my speculation, then, is that we like time-warped video because it is very attention-engaging: we are constantly getting the temporal predictions wrong, and so we are constantly on alert. In support of this, a very engaging style of cinematography is to rapidly alternate between speeding and slowing (think of the battle scenes in 300), thereby holding our attention throughout.

David Eagleman is a neuroscientist and a writer. His book of literary fiction, Sum, debuted internationally this month.

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