By Annabel Gillings
Time, BBC Four
We can't touch time, or smell it. Yet it is utterly inescapable. But, research shows, time is - at least partly - something we control in our heads.
It's four in the morning, and schoolgirl Bethany McQuerry is starting her homework. Her dad, Clay, does the family's washing before going to the 24-hour supermarket. Meanwhile, Bethany's mum and brother, Janelle and Casey, sleep on.
But Bethany is no swot and Clay is no housework obsessive. They just wake up early every single day, whether they like it or not - it's as if they have permanent jet lag.
Bethany and Clay have to get things done early in the morning, because they also fall asleep in the early evening. The difference in timekeeping has divided the family, from North Carolina, US.
"There have been times when I wished we would function the same as other families," says Janelle. "It does make it hard when you're wanting to be together."
Only recently did Clay discover there was a biological explanation for his and Bethany's unusual behaviour, known as ASPS, or Advanced Sleep Phase Syndrome - a disorder of the body clock that shifts their day forward.
The body clock determines our most fundamental behaviours: when we wake up, go to sleep, and eat. But it also determines our physical strength and performance over a day.
However basic the clock's functions seem to us today, its existence was only proved in 1962, by a French caver.
Early doors: Clay and Bethany McQuerry, sufferers of ASPS
Michel Siffre had been planning to study the movement of a glacier through an underground cave, when he realised the enormous potential of his experiment for the field of biology.
"I had the idea of my life: I decided not to take a watch in the cave. I decided to live without time cues," he said.
By isolating himself underground, away from daylight, clocks or routines, he hoped to discover whether the body had its own rhythm. And if so, what it was.
"I decided to live following my feelings of hunger, my feelings of going to sleep. In the cave it's always dark, then your body follows its own sense," said Mr Siffre.
His plan was to call a surface-team of assistants every time he woke, ate, exercised or urinated so every one of his biological functions could be monitored.
Each time, he would give an estimate of the date and time, and the surface-team would compare this with the real time. This he did for two months, before emerging into the real world. Mentally, he had completely lost track of time, but the results showed his body had kept up a rhythm.
While the length of Siffre's waking days varied widely, from 40 hours to just six, a clear pattern emerged. The average length of his days was just over 24 hours. Evolution, it seems, had tailored his body's clock to run closely to the Earth's day length.
It's now known that the body clock is controlled by a tiny pea-sized organ in the brain called the suprachiasmatic nucleus, or SCN. This tiny region commands a chain of chemical and nervous instructions that ripple through the body, controlling how each organ and tissue functions over the 24-hour day.
It's this mechanism that has gone wrong in the case of Clay and Bethany McQuerry. Their early rising is due to the inheritance of a single mutation that throws the whole body clock off kilter.
Does time fly?
While the body clock keeps the rest of us "in synch" with the world around us, that's not our only experience of time. We also have a completely separate sense of time passing.
Mostly, we're pretty good at estimating durations of time - how long you've been online, for example. But people also speak of "time flying" when they're enjoying themselves, or slowing right down in perilous situations such as car crash.
But is there any real distortion of perceived time here, or are people re-inventing their experiences after the event?
Dr David Eagleman, at the site of the free-fall experiment
Psychologist Dr David Eagleman, of the University of Texas, recently set out to nail this assumption, and a BBC film crew was there to record it. He asked volunteer Jesse Kallus to perform a terrifying backwards free-fall of 33 metres.
If the anecdotes are correct, Jesse's perception of time would be slowed by the terrifying experience. But how could one monitor such a thing?
Mr Eagleman came up with a cunning device: the "perceptual chronometer", a wristwatch-like device which flicked blindingly fast between two LED screens.
Normally the flicker would be so fast Jesse could only see a blur. But if time slowed down for him, he might be able to discern the two different screens and read a random number on one of them.
"There's no way to fake this test," says Dr Eagleman, "because if time is not running more slowly, they can't see the sequence."
All Jesse had to do was jump, and read. As he ascended the 33ft metal cage no-one seemed to believe this curious experiment might work.
When Jesse landed, he noted he had seen "98". Dr Eagleman checked. In fact the number was 96. Not quite spot-on, but the two numbers look very similar on a digital screen.
Jesse Kallus, right, preparing for the 33ft drop
"I would have loved it if he had seen the numbers exactly," says Dr Eagleman. "But this at least suggests to me that he's able to take in information faster than he was before".
Further jumps got similar results - all suggesting that time did seem to slow down for Jesse during the jump.
So while time on the clock may be constant, the time in one's brain is elastic and personal - something to remember in a boring meeting when time seems to grind to a halt. Time is not simply a fourth dimension in which we exist. It's something we, at least partly, create in our minds.
Time, a four-part series, starts on BBC Four on Sunday 26 February, at 2000 GMT.
I have a pet theory about time, specifically whether it may not be a myth that it appears to pass more quickly as one ages.
With age, short term memory very often deteriorates. The crux of this theory is that memory is really comprised of remembered events, significant or otherwise.
Thus, as events fade from memory the perceived time lapse between the remaining memories - as there is nothing left to fill the 'gap', must, of necessity, appear shorter.
Bill Shaw, Whitby
I have been wondering how my body manages to wake up before the alarm clock goes off in the morning. I live a somewhat irregular life, but that inner clock does a most remarkable job - accurate 9 times out of ten, as far as I can tell, and to within 15 minutes (always prior to the time set for the alarm!).
Acquaintances of mine, a married couple, appear to suffer from the same syndrome as do the father and daughter mentioned in the article. They cannot stay up late - there is no use trying to socialise normally with them, unless one is willing to accept that things start in the afternoon and stop around 8 p.m. That is not so bad, but on the other hand they seem totally unable to arrange themselves in any other way - the slightest deviation 'from the plan' apparently upsets them.
Conscious time is certainly a curious matter!
D. Fear, Heidelberg, Germany
I'm glad to see that science is finally coming around to understanding what philosophers such as Hume, Kant, and McTaggart knew, and that is that time is something purely subjective. Now if only these scientists can also get rid of the silly idea of time being a "fourth dimension."
Jon C. Miller, Ottawa, Canada
I've often thought that this is true. For example, when I'm at work no matter what I'm doing I know exactly when it's lunchtime and exactly when it's 5 o'clock and time to go home. However, when I'm in my local pub, the Griffin, I can never remember the how long I've there or when I have to go home. I can now blame my SCN for these aberrations.
Marcus Muktasingh, Forest Hill London
Why does time slow down for some people in a crisis situation, yet speed up for others with the same experience?
karen sullivan, Durango, Colorado, USA
I am very sceptical about the experiments described above. Siffre's 1962 experiment could only have explained that we are conditioned into a 24 hour day and not that it is due to evolution. The only way of proving this would be to put a new-born in the cave, which would be unethical. Simiar studies with animals showed a natural cycle produced by the SCN, but with wake/sleep periods much longer than 24 hours.
Richard Gilpin, Bristol, UK
I've lived with this all my adult life, except I cannot sleep until after 3am, and if I wake up before 10am I feel dreadful all day. I have lived several places around the world, and the problem follows me.
Andy, Hong Kong
For me it's very much which hours of night I sleep and not strictly how long. If I sleep around 10pm I get refreshed after 7 hours. But if I sleep after 11pm even after 12 hours of sleep I still wake up exhausted. Also apart from babyhood, I never managed to sleep in the afternoon until I I was in my late teens at university. And to do so I had to draw the curtains and cover up.
Victor, Newport, Wales
The first part of this story has to be a joke. I've changed my bodys' natural rhythm so many times I've lost count. In basic training for the army I went to sleep at 10pm and woke at 4:30. At the stock exchange I went to sleep at 2am and woke at 7. When I became a waiter I went to sleep between 2-4 am and woke at 11am. If the people in the story just tweaked their sleep schedule they'd be fine. No need for another "syndrome."
Thadd, Orlando, USA
Very interesting experiment but I don't quite believe it proves much at all- maybe time doesn't slow but we're more perceptive to a greater amount of information in dangerous situations? A sort of defence mechanism to help us find our way out of danger? Just a thought...
Is this something you have from day one, or is it something you can "get" later on??? It may explain why I'm waking up ready to get up at 2 in the morning.
Carol Daniel , Houston TX USA
While the case described is clearly an extreme one, it's not news to some of us that body clocks vary widely. I have the opposite problem: I have always found it extremely hard to get up early, and even if I do I am rarely functioning properly before late morning. On the other hand, I have no difficulty staying up late: I am rarely in bed before 1.30am, and am frequently still awake at 3am or later. Even if I'm lacking in sleep, I usually find I become more alert at 10 or 11 in the evening, which usually thwarts any plans I might have had for an early night. I have frequently been labelled lazy for my reluctance to get up in the morning, even though I don't think I sleep for significantly longer than most people do, and I'm sure there are those who regard me as dissolute because of my late night habits. I have frequently been told that I would feel so much better if only I went to bed earlier, but I simply don't think this is true - any more than it is that people who are at their best in the early morning would feel better if they tried to imitate my sleep pattern.
Our society is not set up to deal with people with naturally different sleep rhythms, and I am convinced that society as a whole (as well as the people concerned) suffers as a result. Enforcing standard working hours of nine till five will not produce the best results if a significant proportion of the workforce is not functioning at full strength until 11am or later. The advent of flexi-time is a big help, and some of us are lucky enough to have jobs that allow us to plan our own time, but there are many who are not so fortunate, and spend years feeling permanently exhausted as a result of being forced into an unnatural sleep pattern by a world that for some unfathomable reason regards being awake early as somehow more virtuous and valuable than staying awake late.
An alternative explanation for being able to resolve a rapidly flickering "perceptual chronometer" is that rapid eye movements (so-called saccades) cause the different LED images to be projected onto different parts of the retina. This effect can sometimes be seen by glancing from one side of a flickering display (a mains LED alarm clock, for example) to another, suppressing your normal reflex eye-blink. Were the subject's eye movements monitored during the experiment to guard against such changes of fixation point?
Oliver Josephs, London, UK
One of the more interesting articles you have published.
McTavish, Winnipeg Canada
It seems to me that the free-fall experiment could be measuring the effect of adrenaline on eyesight or neural processing of visual input, rather than time distortion. A better experiment might be to have people estimate the passage of time when they're in life-or-death situations, such as relatives of trauma victims.
Jeremy, Atlanta, USA
All they need to do is move a couple of time zones to the east and they will be on normal time, whilst their other families members will easily readjust like the rest of us would.
John Diamond, United Kingdom
I can vouch that time runs slower (or your brain speeds up in a crisis). In my first parachute jump my 'chute didn't open correctly. To cut a long story short, I sorted it, and landed safely, but my instructor asked how long it took me to sort myself out. I replied that it was probably about a minute. He replied, "It took you less than 7 seconds.....".
I still swear to this day that it took me a minute in my mind.
Simon Howarth, Preston, UK
Brilliantly insightful. I am a traumatologist who deals with the issue of memory formation all the time. When one imagines the ways in which memories can vary, one seldom considers the possibility that the perception of time itself might be one of those variables. Very interesting implications indeed.
Andy Davies, Albany, NY
I know when I am ill (or going to be ill) as time seems to go inexorably slowly. The night after my spinal surgery, it was like the minutes of the hands never moved, but once I got better, time returned to "normal". I find now that time "slowing down" for me is an indicator that I am brewing an illness. Weird but true!
Nina Bunton, Bristol, UK
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