I'm on holiday this week so I'll be reposting a few articles from the old Wordpress incarnation of Not Exactly Rocket Science. Stay with it though - these are five good'uns.
In The Matrix, when an agent first shoots at Neo, his perception of time slows down, allowing him to see and avoid oncoming bullets. In the real world, almost all of us have experienced moments of crisis when time seems to slow to a crawl, be it a crashing car, an incoming fist, or a falling valuable. Now, a trio of scientists has shown that this effect is an illusion. When danger looms, we don’t actually experience events in slow motion. Instead, our brains just remember time moving more slowly after the event has passed. Chess Stetson, Matthew Fiesta and David Eagleman demonstrated the illusion by putting a group of volunteers through 150 terrifying feet of free-fall. They wanted to see if the fearful plummet allowed them to successfully complete a task that was only possible if time actually moved more slowly to their eyes. The task was deceptively simple. They merely had to read two numbers that were displayed on a wrist-mounted machine called a ‘perceptual chronometer’. Like a clunky digital watch, the device was programmed to show two numbers, but the catch was that the glowing digits were rapidly alternated with their negative images, where the area around the number is lit.
As the two images flicker more and more quickly, there comes a sudden point where they blur into a single uniform square of light. At this point, the rush of visual information overwhelms the brain of the volunteer, who is unable to resolve the two images apart. The trio of researchers tuned the device to each volunteer’s threshold of resolution – the point where they only just failed to read the numbers. They reasoned that if a scary experience really made time slow down for the volunteers, even by a tiny amount, the flickering numbers should slow down enough to pop out of the blur. The effect should be like a slow motion camera, resolving the blur of a buzzing fly into individual wing beats. To provide the necessary fear, Stetson took his volunteers up a SCAD tower (Suspended Catch Air Device) where they were strapped to a harness and dropped from a height of 150 ft onto a safety net. As they plummeted in free-fall, they had to try and read the numbers flashing from their wrists, while an eagle-eyed experimenter watched from the top to rule out those who kept their eyes completely shut.
The volunteers failed. In fact, they read the numbers just as inaccurately as a control group who did the same task while staying on the ground. Neo, they weren’t. Unlike the slowed bullet-time of The Matrix, a person’s perception of events in time doesn’t speed up when danger looms. However, the volunteers did have a distorted view of time during their fall. Before they ascended the tower, Stetson asked each volunteer to reproduce how long a compatriot took to hit the net using a stopwatch. They were then asked to do the same after they’d had a go themselves. On average, the volunteers estimated that own experience took 36% longer than that of their fellows. Time didn’t slow down – the volunteers just remembered that it did. Stetson and co believe that people lay down richer, denser memories when they experience shocking events. These ‘flashbulb memories’ include emotional content, which involves the brain’s emotional centre – the amygdala (see this earlier post about flashbulb memories in 9/11 survivors). As these memories are played back, their unusual richness could fool the brain into thinking that the recorded events took up more time than was actually the case. Reference: Stetson, C., Fiesta, M.P., Eagleman, D.M., Burr, D. (2007). Does Time Really Slow Down during a Frightening Event?. PLoS ONE, 2(12), e1295. DOI: 10.1371/journal.pone.0001295More on perception: