How to use slow motion for maximum impact

Have you ever wondered if your nervous system can overcrank like a camera does, gathering several times more information at high speed?

In the movie Limitless, this is the superpower that the fictional drug “NZT” offers struggling writer Eddie Morra (Bradley Cooper). Eddie is able to repeatedly work his way out of crisis situations, to finish his novel in a few days and to game the stock market by accessing not only present experience but past memories at superhuman speed.

No doubt you’ve had at least one sudden, life-threatening, traumatic experience—an automobile accident is the classic example—in which the entire experience seems to play out in slow motion. You see and remember things much more vividly than in everyday life, and they seem to play back in slow-mo.

Is this your mind actually working faster—overcranking? if so, what does that say about how your audience experiences slow motion in your films? What if there were a scientific way to understand slow motion perception—the term for this phenomenon?


David Eagleman wondered this as well. He makes videos as the host of The Brain with David Eagleman on PBS, but his day job is as a neuroscientist who heads the Center for Science and Law at Stanford. His hypothesis, “crudely speaking, are neural ‘snapshots’ clicking faster during a high-adrenaline situation?” led to a method to evaluate whether or not that was the case.

The experiment was set up as follows. The subjects were put into a situation that would feel life-threatening: dangled from a cable in mid-air, hundreds of feet off the ground and dropped face-up in freefall. In the few seconds that they spent falling backwards into a net, they used “palm-top computers” to perform “psychophysical experiments” that they also had practiced on the ground. If they were able to perform the experiments more quickly during this truly terrifying simulation, it would demonstrate that human perception actually works more quickly when humans are in extreme danger.

The result? The subjects did not process information more quickly, but they did remember more details from the surrounding environment. By monitoring the brain, it was found that this result was accounted for by increased activity in the amygdala. More information is “recorded,” which makes the memories much more detailed—which sounds a little bit like overcranking, but is more like a multi-camera shoot. “In this way, frightening events are associated with richer and denser memories,” explained Eagleman. “And the more memory you have of an event, the longer you believe it took.”

The amygdala, highlighted in an MRI

Evidently, the mind evaluates the information contained in sudden, potentially life-altering (or life-ending) emergency situations to be significant to your survival. So it lays down more memories, and thereafter, the experience feels like slow-mo.

How does slow-motion feel?

The question is meaningless. It all depends—by itself, a slow motion shot may have more information, but it has no more meaning than any other. The first recording moving image in history was slow motion, and it wasn’t created to tell a story, but instead to settle a bet over whether all four legs of a horse in full gallop all leave the ground at once:

Our visual literacy and intelligence as a species seems to have evolved—one can easily see that the galloping horse gets air—but we still love slow motion replay as a way to see detail. But that’s not emotion, it’s Monday Night Football.

We don’t use instant replay much in storytelling, except maybe for comedic effect. Let’s suppose for a second that there are three basic reasons to slow down a shot:

1: Slow-mo creates a beautiful image that includes startling detail. In the age of the two-year-old phone in my pocket that ramps seamlessly in and out of 240fps, you can see these everywhere from television commercials to blockbuster trailers.

2. Slow-mo is crucial to a science fiction storyline in which characters can manipulate time itself. 

3. Slow-mo is used to punctuate a peak emotional moment in a story. More on that in a moment. First, let’s take a quick look at the question…

What does slow motion actually do?

Overcranking footage and playing it back at regular speed does more than make it play slower.

Slow motion literally makes you spend more time and attention on the subject. But slow-mo footage is also, by necessity, cleaner and sharper than the standard 24fps film shot with an 180 degree shutter.

Filmmakers have used a fast shutter at standard 24fps for the kind of high-adrenaline sequences where others might just go with slow-mo. 

One thing that is unusually powerful about the Omaha Beach landing in Saving Private Ryan is that it recreates the heightened clarity that occurs when the system is flooded with adrenaline. Had Spielberg shot this sequence using slow-motion instead, however, it might have felt nostalgic, like a memory, rather than immediate and deadly.

So is the only good use of slow-mo to punctuate near-death experiences?

No. If you’ve ever felt bored, restless or disappointed by slowmo as a storytelling device, it may be that it didn’t connect with feelings of extreme trauma, but at the other end of the scale,  it can also evoke extraordinary euphoria.

Slow motion footage can cue the audience that we are seeing something that someone in the story will never forget. A child regularly lays down extra memories that may be recorded elsewhere in the brain; rather than fear, these are associated with experiences that are entirely new and unfamiliar.  

This helps explain a related phenomenon of time perception. To an older person, life seems to progress much more quickly than it did during childhood. When you’re a child, many more situations are entirely unfamiliar. These memories of discovery, surprise and delight also evoke slow motion perception.

The two emotions most associated with significant experiences that replay in slow motion are those of fear and awe. You can punctuate a moment by slowing it down, and you can design a fascinatingly elaborate scene for high-speed photography. But to make a sequence resonate with a viewer’s experience is to relate the scene to situations that stretch us to survive, or even to learn something about the world that we never previously understood so clearly.

What are your favorite slow motion sequences, and what makes each one stand out? Here’s a supercut to spur your memory.

Mark Christiansen

Author at and of the After Effects Studio Techniques series (Adobe Press); VES Member, VFX Artist and Supervisor on Avatar, Pirates of the Caribbean At World's End, The Day After Tomorrow, Beasts of the Southern Wild; Founder of New Scribbler (developers of Cinefex for iPad); past employee of Lucasfilm, Adobe and

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