We see it so often in movies that it’s a cliché…something terribly stressful happens and our protagonist, either through otherworldly skill, powers or pants wetting fear witnesses everything slow down around them. In the case of skill and powers this allows them to dodge bullets/punch faces/eat sandwiches.
When it’s fear they mostly get to juuuust avoid whatever was coming towards them.
It’s an overused trope in written fiction too, but it’s somewhat based in reality. So what’s really going on when time seems to slow down.
Partly it’s your body freaking out and dumping a huge dose of adrenaline into your bloodstream. This quickens your reaction time, forces more blood through to your muscles and generally prepares you to either knuckle up or run away. For a long time it was thought that it also slowed the perception of time.
The anecdotes certainly supported this: people reporting everything from being able to see punches coming in slowmo, but not being able to avoid them, to seeing what seemed like barrel sized spent cartridges float by police officer’s faces during gun fights.
I never got that. Instead I came away from the more terrifying experiences of my life feeling like they’d gone by very, very quickly but that I could remember everything that had happened in great detail, so in my memory I could replay things at a far slower rate.
And science has vindicated me* (oh ego, what would I ever do without you?). Woo!
As it turns out time perception during a terrifying or otherwise adrenalizing event doesn’t change, but our brain takes the adrenaline dump as a signal that it had better remember what’s happening in great detail because it doesn’t want a repeat of whatever is going on.
There are exceptions of course, such as trauma-induced amnesia, but in most cases this memory encoding theory seems to hold true. We don’t perceive things as happening any slower while they’re actually happening, but we remember the event as if we could.
I think this is a useful trick to employ when you’re writing a fight scene, or in fact any scene where your main character’s heart rate doubles over the space of a few seconds. Describe the actual fight as being at blinding speed (most fights are over within thirty seconds) but have the character remembering the fight in such detail that it seems as if time has slowed down. I think this adds a great deal of urgency to the feeling of your fight scenes without forcing you to reuse a tired trope.