When BBC reporter Alan Johnston was held captive in Palestinian-controlled Gaza, he had plenty of time to fill but no accurate method of measuring it. With no wristwatch, no books, or pen and paper, his only means of guessing how much time had passed was by studying the lines of light visible through the shutters and the shadow that moved slowly across the walls as he willed each day away. The five Islamic calls to prayer also allowed him to work out the rough time of day, but he soon lost track of the date. "I made a mark on the door in the traditional clichéd prisoner way, but for a while I was worried about what the guard might do if he saw these marks on the door of his flat. He was going through quite bad moods at the time, so I started making etching lines on the edge of my toothbrush instead, but it was still quite easy to become uncertain about the date, and soon I was adrift from time."
In fact Alan Johnston spent almost four months in that flat, but at the time he had no idea how long he would be detained, or whether he would live or die. "Suddenly time becomes like a living thing, a crushing weight that you have to endure. It’s endless, since you don’t know when you’re going to be freed, if ever. There’s this great sea of time ahead of you that you have to keep ploughing through." To pass the hours, Alan invented mind games, setting himself tasks such as developing the best possible intellectual attack on the idea of apartheid, or trying to write poetry and stories in his head. But with no pen and paper to record his thoughts, it became an exercise in memory, "If you write seven crap lines of poetry, you’ve got to remember them before you can move on to the eighth, and then when you’ve written the ninth line, you’ve got to ask yourself whether you still remember line five." Eventually Alan developed his own mental strategy for coping with the hours, a strategy that used the concept of time itself.
There were two elements holding sway over Alan’s life as a hostage: his captors and time. Here, I’ll examine the conditions under which time can become so warped that it slows down to the unbearably protracted pace experienced by Alan Johnston. It is not surprising that time dragged for him, locked in one room and deprived of all stimulation, but I’ll also be covering other, more peculiar circumstances where time expands. It is the mysterious flexibility of time that makes it so fascinating, but before we get to that, let’s consider why our ability to sense the passage of time is so important, both to us as individuals and as part of society.
Accurate timing is essential for communication, cooperation and human relations in more ways than you might expect. It’s obvious that any activity involving two or more people requires the coordination of timetables, but even something as apparently simple as a conversation demands split-second timing. To produce and understand speech, we rely on critical timings of less than a tenth of a second. The difference between the sound of a ‘pa’ and a ‘ba’ is all in the timing of the delay before the subsequent vowel, so if the delay is longer you hear a ‘p’, if it’s short you hear a ‘b.’ If you put your hand on your vocal cords you can even feel that with the ‘ba’ your lips open at the same time as you feel your cords start to vibrate. With the ‘pa’ the vibration starts a moment later. This relies on timing accurate to the millisecond. Even the timing between syllables can be crucial to a phrase’s meaning. With Jimi Hendrix’s lyric, "Excuse me while I kiss the sky," just a fraction of a second difference in timing is what gives you the famous monde-green, "Excuse me while I kiss this guy." In order to coordinate limb and muscle movements, we need to estimate milliseconds, while the appraisal of seconds allows us to do everything from detecting rhythm in music or kicking a ball to deciding whether it’s faster to walk along the travelator at the airport or on the floor around the side. (Answer: it depends. Researchers at Princeton University found that taking the travelator usually slows you down because you tend to reduce your pace, or -- more irritatingly -- get stuck behind people who stop walking as soon as they get on. An empty travelator will get you across the airport faster than walking on the floor alongside it, but only if you don’t decide to stand still yourself.)
Our sense of timing isn’t perfect, yet on the whole our brains are able to conceal this, presenting us with a world where time usually feels smooth and consistent. A badly dubbed film has to be quite bad for us to notice the discrepancy; studies have shown that if the mismatch is anything below 70 milliseconds our brain goes along with our expectation that if we can see a person’s mouth moving and we can hear a sound that matches it, then they must be occurring simultaneously. Yet once people are told that they don’t match, they can then work out whether the pictures are ahead of or behind the sound. So it’s not that we can’t detect these discrepancies, it’s that unless we are alerted to a problem the brain assumes that sound and sight fit together because that’s what we’re used to. Some of our senses are better at timing than others; it’s much easier to remember an auditory rhythm tapped out in Morse code than the same series of dots and dashes written down. We are tagging events in time in order to make sense of them.
So our minds create for us an experience of time which not only feels smooth on the whole, but which we can share with others, allowing us to coordinate our activities. Despite this, time never stops surprising us. The reason time is so fascinating is that we never appear to become accustomed to the way it seems to play tricks on us. Throughout life, we find it warps. We comment on weeks that seem to rush by, while others drag. We fly into a time zone that is behind us and create the illusion of cheating time, of living a few hours of life twice. Fly the other way, and we wonder what happened to the time we missed. Despite the longer evenings we get when the clocks go forward in spring, there is still a nagging feeling that an hour has been stolen from us. And when the clocks go back in the autumn we feel a sense of satisfaction at gaining an extra hour which marginally lengthens the weekend. Although our rational side is well aware that this extra hour is just a trick of the clock, we still feel we are losing or gaining time, and this begins to illustrate how much of our relationship with time is based on illusions we create in our own minds.
In 1917 the wonderfully named researchers Boring and Boring conducted an experiment in which they woke up sleeping people and asked them to estimate the time, something the participants (including Mr. and Mrs. Boring themselves) were usually able to do successfully to within 15 minutes. But not everyone can do this. Although most of us find time slightly mystifying, for some of us it is utterly inscrutable. Eleanor is 17 and tells me she has never quite "got time." She is aware that she cannot judge its passing in the same way that everyone else seems to. When she wakes up in the morning, unlike the people in Boring and Boring’s study, she has no idea what time it is and this continues all morning. She does not seem to sense time moving on. "I don’t know the time until lunch-time, when I start feeling hungry. I deliberately look for clues like that to work out how much time is passing." At school, she finds that while other people are able to make a rough guess, she can get the time wrong by several hours.
Without checking the clock she has no idea whether a lesson is near the beginning or about to end. She inadvertently leaves her mother waiting where she has come to collect her because time doesn’t feel as though it’s passing, so she forgets to check her watch. So far the inconvenience has been mainly for her patient parents, but now that she’s taking exams, she’s beginning to notice the problems this lack of time perception can cause. While other students plan how much time to spend on each question, unless Eleanor constantly monitors the clock she doesn’t notice that it might be time to move on. Her case illustrates that we don’t all share the exactly the same concept of time. Eleanor also has dyslexia, and this could hold the key to her difficulties with time perception.
For Eleanor time is constantly surprising, but in some circumstances, it can be just as unnerving for the rest of us. We marvel, somewhat anxiously, at where the weekend went and how fast other people’s children seem to grow up, or despair at how time drags in an airport queue. Imagine you are watching the final five minutes of a football match, and how differently that time passes depending on whether your team is winning or losing. If they're 1–0 down five minutes simply isn’t long enough. If they’re 1–0 up, time appears to stretch, giving the other team far more chances to level the score than they deserve. Think of a journey and how the way back always seems shorter. With fewer new memories to fill the time, everything seems familiar, and it feels as though the distance is much shorter, unless, as the 19th century philosopher and psychologist William James observed, you are retracing your steps because you have lost something. Then it seems endless. Time plays tricks on our minds.
As young children grow up, these mysteries of time are something they begin to observe for themselves. I asked two brothers what they had noticed about time passing. "When you have to brush your teeth for two minutes, that seems like a long time, but when you’re watching TV, two minutes goes really fast," said eight-year-old Ethan. His 10-year-old brother Jake observed, "If you’re waiting for someone in the car while they go shopping, it seems longer than if you do the shopping yourself." These children have already noticed that time is deeply subjective. Our sense of time passing can even depend on the way we feel about our physical well-being.
So what are the major factors that cause time to warp? The first is emotion. An hour at the dentist feels very different from an hour working up to a deadline. If we look at pictures of serene faces, we are quite good at guessing how long we watched them for, but show us a series of frightened faces and we overestimate the time that passed. However, the best illustration of the power of emotion to skew our perception of time is more dramatic -- the slowing down of time when you are fighting for survival; when, like Chuck Berry falling through the sky, you are genuinely in fear for your life, one minute becomes elastic and can feel like 15.
Time Slows Down When You're Afraid
Alan Johnston had long known that kidnapping was a risk that came with the job of a foreign journalist in Gaza. It was an eventuality he had rehearsed in his mind before it happened in real life. When that fated day came around, and he saw a man get out of a car holding a pistol, his initial thought was, "So this is how being kidnapped feels, and this time I’m not just imagining it." Then for a while everything went into slow motion. "You can almost stand back and watch yourself going through it," he told me.
Several weeks after he was captured, his captors gave him a radio. One night he heard a story on a BBC World Service news bulletin that made time slow down once more. "They said that I’d been killed." He began to think that perhaps the kidnappers’ public relations department had got ahead of itself and released the news too early. Was this what they were planning to do tonight? "It seemed more likely that they would want to keep me alive because that would be more useful to them, but when you’re lying in the dark hearing that message going out to the world and they say they’ve killed you, there’s a part of you that wonders if they’re going to do it. Maybe tonight’s the night." For Alan, this felt like the longest night of his four months in captivity. Time definitely slowed down.
When people are afraid they might die, whether in a situation like Alan’s, in a plummeting glider like Chuck Berry’s, or in a car accident, they often report that the event lasted far longer than was possible. Somehow, in just a few seconds they find the time to consider a great number of topics in detail. They think through their past, they speculate on the future and all the while they scan their memories for any piece of knowledge from anywhere that might help them to survive. This experience of time deceleration through fear is well-established, and -- provided you feel frightened -- time can distort even in a non-life-threatening situation. When people with spider phobias were instructed to look at spiders for 45 seconds (I am amazed they ever agreed to take part in this experiment), they overestimated the time that had passed. The same happened with novice skydivers. If they were watching other people, they gauged the duration of the fall to be short, but once it was their turn, time seemed to move more slowly, and they overestimated the minutes they spent in the sky.
Throwing People Off Buildings
Is this deceleration of time simply an illusion, or does the way we process time actually slow down when we are in fear for our lives? If the brain does process time differently when we are terrified, then it should also be able to process sights that are usually too rapid to see with the naked eye. To discover whether this is true, all you need to do is to scare people out their wits and then give them a test during that terror. One man knew just how to do it, and -- in what appears to be something of a theme in research on time perception -- was prepared, along with his brave volunteers, to go to extraordinary lengths to achieve it.
On the day of the study it was particularly windy. This was perfect. For the 23 volunteers standing on top of a tall tower in Texas, the wind injected a little extra anxiety into an already fraught situation. If this experiment was to work, real fear was essential. The neuroscientist David Eagleman, from Baylor College of Medicine in Houston (the same neuroscientist who wrote the best-selling imagined stories of the afterlife, "Sum"), warned his volunteers to stay well back from the edge until it was their turn to climb up inside a 33-foot-high metal cage mounted on the roof. He radioed down to the team on the ground 150 feet below to check that everything was ready, then turned to a line of digital wristwatches with giant faces. These perceptual chronometers were set to alternate very quickly between two screens showing random numbers. They flicked so fast that to the naked eye they looked like a blur. Eagleman wanted to know whether terror would speed up a volunteer’s sensory processing enough for them to read the numbers, which the calm human brain fails to register. Perhaps it’s not that time slows down when we’re afraid, but that our minds speed up.
Eagleman had previously experimented with taking the volunteers on a rollercoaster, but they just weren’t scared enough; and in fact many seemed to enjoy the experience. It was time for something more drastic -- freefall. Eagleman knew that no one would agree to take part in this experiment unless he had shown that he was willing to do it himself. Strapped into a harness, he was dangled over the side of the tower block and dropped, backwards. (Forwards wasn’t sufficiently frightening.) Then he did it again. And then again. Before the third attempt he was convinced that he would be less terrified; experience would surely tell his brain that he would be fine. But no, he told me, "It was still beyond scary." Then it was the turn of a young man called Jesse Kallus. Just as Eagleman had been before him, Jesse was thrown off the building, and by the time he had been caught safely at the bottom, he had reached a top speed of 70 miles an hour.
Everyone who took part in the experiment reported that time felt as though it decelerated. The fall stretched every one of those unbearably petrifying seconds. So the first element of the study had worked; the desired effect of subjective time dilation had been achieved. Yet still the figures on the watch face flickered too fast for their brains to perceive them. David Eagleman had demonstrated that time itself doesn’t actually slow down when we’re afraid, and nor does the brain’s sensory processing speed up. What changes is our perception of time -- our mind time.
So how does this happen? It is true that fright does etch strong memories into the brain, and memory is one of the key factors in making time warp. When people are shown a video of a bank robbery lasting exactly 30 seconds, two days later they tend to guess that it lasted five times longer than it did. The more disturbing a version of the video they are shown, the greater their overestimation of its duration. After a stressful event, we often recall every single detail of what we saw, heard or even smelt. The richness and freshness of these memories contributes to our sense of how long it lasted. We become accustomed to a certain quantity of memories fitting into a certain time-frame. Usually this serves us well, but during a life-threatening incident the intensity of the experience results in the creation of more memories. Every second feels brand new, which causes us to judge the event to have taken longer than it really did, to have happened in slow-motion. This sensation is amplified by the fact that in a car accident, for example, the mind focuses on the elements of a situation necessary for survival and filters out anything inessential such as the scenery, the songs changing on the radio or the number of cars that pass. These are the cues which would normally help to assess time passing. Without them, once again time warps.
The big question is whether the combination of the plethora of memories and the absence of cues to time passing is enough to make time decelerate this drastically? There is a more radical explanation -- is it possible that the way the brain actually measures time could make it feel as though it slows down? If the brain counts time by monitoring its own processes, when it moves extra fast in an emergency this could cause it to count more beats and to believe that more time has passed. So while the brain is racing to save itself, so is its clock. Before that, there are other curious factors that distort time. The life-threatening, mind-racing moments of intense concentration are not the only occasions when time decelerates. The opposite -- having nothing on which to fix your mind; in other words, sheer boredom -- has a similar, though less extreme effect, as do a series of other experiences.
Excerpted from "Time Warped: Unlocking the Mysteries of Time Perception" by Claudia Hammond. Published by Harper Perennial. Copyright 2013 by Claudia Hammond. Reprinted with permission of the publisher.