Is our experience of time worse than memory?
IVAN AMATO
Cover: Eleni Debo
Cognitive Science
Nothing can win the attention of the brain more than in the moment of crisis. John Hockenberry, a well-known journalist and commentator, said he experienced such moments about forty years ago. Even today, that moment is still vividly remembered and often comes to mind. In his words, it's like playing back in slow motion.
At the World Science Festival in New York in early June 2014, Hawkenbury launched a panel discussion on the perception of time. "About 38 years ago, I was riding on a highway in Pennsylvania," he recalled. I was sleeping in the back of the car. I woke up to find the driver asleep too. The car was off the road. The passenger sitting next to him looked as if he was slowly passing the driver, grabbed the steering wheel, turned around with all his strength, and then the car began to drift to the right. After that, we slowly hit the fence, the car flipped in the air, and I intuitively felt that my life was about to change. ”
— Eunho Lee
Retired fire captain Richard Gasaway calls this apparent slowdown in time "tachypsychia," roughly understood as "rapid consciousness." To study "situational awareness," write blogs, and give speeches, Gasavi conducted hundreds of interviews. From this, he concluded that "this phenomenon afflicts many first responders." Gassaway believes he has also experienced a "neural time warp" firsthand. This reinforced his belief that the phenomenon was part of the overall stress response. This is a dangerous phenomenon for first responders, he said, because it can distort our situational awareness and influence the process by which we make decisions.
But is neural time distortion a fact or an illusion? David Eagleman of Baylor Medical School conducted an experiment to answer this question. He and his colleagues invented a "perceptual stopwatch" shaped like a watch. This stopwatch displays red numbers back and forth along with their negatives (shiny red background and non-shiny numbers)*. The speed at which the stopwatch is displayed back and forth exceeds the critical fusion frequency (CFF) of the image, which is the threshold at which a uniform image can be fused during the toggle. Igman hypothesized that if he could scare people when they looked at the stopwatch, their CFF would burst into slow-motion perception mode. This way, they can instantly see the numbers on the stopwatch.
*Translator's note: The stopwatch switches back and forth between two screens, one is that the number is red and the background does not glow; the other is the same number, but the number does not glow, and the background is red.
<h1>Time hasn't slowed down</h1>
To carry out the experiment, Igman led 20 people to a zero-gravity playground in dallas. He took the participants to a 16-story bungee jumping facility called a hollow dunk, where they free-fell from a height of 31 meters with a stopwatch until they landed on the net. The participants needed to keep an eye on the stopwatch during their 2.5-second thrilling landing. One participant closed her eyes the whole time, so she didn't provide any data.
Data from other participants make it clear that no one can see the numbers during the descent. But when they estimated when they were falling (using a stopwatch to record time with a stopwatch in their hands as they recalled it in their minds), the average time they estimated was one-third longer than those who watched them in free fall estimated. Igman concludes that in this torturous situation, the subjective experience of slowing down time is a process of memory, not a true perception of time. In short, time hasn't slowed down for anyone. Igman explains: "Under normal circumstances, most of the things that go through the sensory center you forget. But in life-threatening situations, everything is recorded and preserved in memory. He continues that because the brain is not used to this kind of high-information density memory, "it will understand that all this must be happening slowly." ”[1]
— Noma Bar
However, what if some subject is not affected by the "impending crisis", but has some kind of mental or cognitive defect? Igman and his colleagues asked subjects with schizophrenia and control groups to identify stimuli (such as letters, pictures, and faces) from a series of rapidly flashing screens. The results showed that "a strobe of up to 100 milliseconds for you can be up to 120 milliseconds for schizophrenics," Igman said. He speculates that this 20 percent difference in sensory levels masks time turmoil in high cognitive abilities. This, for example, makes a person's conventional self-talking conversations difficult to describe. In this case, Mr. Igman said, the voices often heard by people with schizophrenia are likely to be because they subjectively try to understand the experience of time chaos. [2]
According to a cross-species analysis published in Animal Behavior, the finite frequency of critical fusion of humans indicates that humans belong to a larger group that includes many animals in the animal kingdom. The average human CFF is 60 strobes per second, which is why the TV's strobe speed is equal to or higher than this frequency. In the animal kingdom, CFF can be as low as 6.7 for a sea toad (Bufo marinus), as high as 108 for a ground squirrel or as high as 240 for a common green-headed fly. In general, animals with higher metabolic rates or smaller sizes have a higher CFF. [3]
<h1>The wonder of the difference in CFF</h1>
These differentiated CFF values seem to provide some fantastic explanations. No wonder flies can escape your hand so easily. CFs of up to 240 allow them to see the hand you're waving at it as they struggle through the syrup. What about the aviation stunts of birds stunts staged in intricate vegetation? With a CFF of 100, they are likely to visually look around at superhuman speed, so they can make faster adjustments in the air.
There is evidence that this temporal factor is critical to ecological competition on Earth. One of the authors of the article, Animal Behavior, Andrew Jackson, is also a zoologist at Trinity College Dublin. "Time perception may be an important but overlooked indicator of ecological niche differentiation," he said. For example, when catching a squid, a cold-blooded swordfish will have warm blood rush into the eyes to increase its own CFF. Jackson said: "When they want to catch relatively slow squid in the cold water of the deep sea, this ability must give them a huge advantage." In this way, the swordfish is like a visitor from another time and space... The odds of a squid surviving are slim. "Humans can't increase CFF with this practice of getting warm blood into the eyes or brain. Doing this is like heating human tissues into high heat, breaking up proteins and forcing cells to commit suicide.
That being said, Jackson believes that people's CFFs may be slightly different, which can also help us explain differences in personality, talent, choice, and perception. "If a person's CFF is higher than other team members, then he actually has the potential to react quickly, and this speed is incredible for other team members," he said. I wonder if this explains this phenomenon: sometimes when you play football, you are very skilled and can easily pass. You'll feel like the ball is slow for you. Jackson's work on hand is some research about people's inherently different critical fusion frequencies and how people's CFF changes under different circumstances. "The most interesting thing is whether these differences can have an impact on our lives," he said. ”
— BIG MOUTH
Jackson is applying for funding to study these issues. He said that if money wasn't an issue, he'd love to recruit fast-action fanatics like Bruce Lee and LeBron James, because we can trust their extraordinary CFF to play a role in their amazing martial arts. Regarding the possible link between CFF and cognition, Jackson said he was interested in whether low-CFF people could notice subtle cues like facial expressions. Jackson also wants to explore another thing: whether we can train people to improve their CFF in order to improve sports performance or help treat temporal barriers.
The researchers caution that the small amount of data we currently have in our hands is not enough to establish a link between CFF and subjective time perception, let alone draw any conclusions about CFF in humans. But the differences in CFFs between animals and animals, between ordinary people and people with mental illness, and the subjective experience of time, leave us with a question worth pondering: Will someone live in another dimension of time like a swordfish?
bibliography
[1] Stetson, C., Fiesta, M.P., & Eagleman, D.M. Does time really slow down during a frightening event? PLoS One 2, e1295 (2007).
[2] Parsons, B.D., et al. Lengthened temporal integration in schizophrenia. Neuropsychologia 51, 372–376 (2013).
[3] Healy, K., McNally, L., Ruxton, G.D., Cooper, N., & Jackson, A.L. Metabolic rate and body size are linked with perception of temporal information. Animal Behaviour 86, 685-696 (2013).
Translation: Anna Wen
Reviewer: Cao Anjie
Typography: Fusisi
About the Author:
Ivan Amato
A science and technology writer living in Silverspoe, Maryland. He is the operator of the D.C. Science Cafe.