A neuroscientist dropped people from a 150-foot tower in Dallas to find out if time really slows down when you think you're about to die

In 2007, neuroscientist David Eagleman and his colleagues set out to investigate one of the strangest experiences people report during moments of extreme fear: the feeling that time suddenly slows down.

People involved in car crashes, falls and other life-threatening situations have often described the experience as if the world were moving in slow motion. But was that actually happening inside the brain? Did fear somehow allow people to process information faster, giving them a few extra mental “frames” every second?

Eagleman and his colleagues designed an experiment to find out.

The terrifying experiment

They took volunteers to the Zero Gravity amusement park in Dallas, Texas, where participants were placed at the top of a 46-meter SCAD tower, roughly 150 feet high. They were then released and experienced about 2.49 seconds of free fall, dropping roughly 31 meters before landing safely in a net.

The researchers needed a way to determine whether the volunteers' brains were actually processing visual information faster during the terrifying fall.

So they created something called a perceptual chronometer.

The device was strapped to each participant's forearm like a wristwatch. It displayed rapidly alternating digits and their negative images at adjustable speeds. At normal speeds, the numbers could be identified. But once the images alternated quickly enough, they blended together and became impossible to read.

Before the jump, researchers determined each participant's normal visual threshold. Then, during the free fall, the device displayed numbers slightly faster than that threshold.

The logic was simple: if fear really put the brain into “turbo mode,” the volunteers should suddenly have been able to read the digits.

They couldn't.

The participants' performance during the fall was no better than that of people who performed the same experiment while remaining safely on the ground. There was no evidence that their temporal resolution — essentially their ability to distinguish rapidly changing visual information — had increased.

The strange twist came afterward

But something very strange happened when the researchers asked the volunteers to estimate how long their own falls had lasted.

They remembered the falls as significantly longer than they actually were.

The real fall lasted 2.49 seconds. Yet when participants later estimated its duration, their estimates increased by an average of 36%.

That result created the real mystery.

If their eyes and visual systems weren't processing information faster, why had those few seconds felt so long?

It wasn't perception. It was memory.

The researchers concluded that the sensation wasn't caused by time literally slowing down or by the brain suddenly seeing the world in cinematic slow motion. Instead, they suggested that the effect was linked to memory.

The paper proposes that highly emotional and frightening events may receive richer encoding in memory. When those memories are later recalled, the amount of information packed into the experience can make it seem as though the event lasted much longer than it really did.

In other words, the volunteers weren't gaining extra seconds while they were falling.

They were gaining more memories of those seconds.

That distinction matters. The experiment found that subjective time can stretch without a corresponding increase in the brain's ability to perceive rapidly changing information. The researchers therefore argued that our sense of time isn't one single mechanism that simply speeds up or slows down.

Why a few seconds can feel much longer

The finding offers a possible explanation for why people sometimes describe terrifying experiences as happening “in slow motion.”

During an ordinary moment, much of the information passing through our senses is never retained as a detailed memory. But a highly frightening event can become unusually salient. When we later recall it, the experience may seem much more extended because the memory contains so many details.

The Dallas experiment did not prove that the amygdala literally records memories at a specific “higher density”; the researchers instead speculated that emotional-memory mechanisms involving the amygdala could contribute to richer encoding.

So when someone says that a terrifying moment happened “in slow motion,” they may not literally have seen more frames of reality.

Their brain may simply have recorded the experience differently — and when they looked back on it, those densely remembered moments felt as if they had taken much longer.

The clock didn't slow down.

The fall didn't actually become longer.

Their memory made those few seconds feel that way.