杏吧原创

MIKE HALL has taught himself to stretch time. He uses his powers to make him a better squash player. 鈥淚t鈥檚 hard to describe, but it鈥檚 a feeling of stillness, like I鈥檓 not trapped in sequential time any more,鈥� he says. 鈥淭he ball still darts around, but it moves around the court at different speeds depending on the circumstances. It鈥檚 like I鈥檝e stepped out of linear time.鈥�

Hall, a sports coach from Edinburgh, UK, is talking about a state of mind known as 鈥渢he zone鈥�. He puts his abilities down to 12 years of studying the martial art t鈥檃i chi, and now makes a living teaching other sportspeople how to 鈥済o faster by going slower鈥�.

For most people, getting into 鈥渢he zone鈥� at work or home isn鈥檛 a realistic option. But the idea of stretching time 鈥� or at least having more control over its frantic pace 鈥� is an attractive one (see 鈥淪low living鈥�). And there may be things we can do. There is a growing understanding of how our brains measure the passage of time, and it turns out we have more conscious control over it than previously thought.

Biologists traditionally divide our timekeeping abilities into three domains. At one end are circadian rhythms, which control things such as sleep and wakefulness over the 24-hour period. At the other end is millisecond timing, which is involved in fine motor tasks. The middle ground 鈥� the seconds-to-minutes range 鈥� is known as 鈥渋nterval timing鈥�. This is the system through which we consciously perceive the passage of time.

Until recently, interval timing was something of a psychological backwater, says John Wearden of Keele University in Staffordshire, UK. While the biological basis of the circadian and millisecond clocks were fairly well understood, no one could find the biological stopwatch we use for interval timing. As a result, many thought that perception of time was little more than a side effect of general cognition and refused to see it as a discipline in its own right. But now, parts of the brain have been singled out as being specialised for timekeeping, and we are getting tantalising glimpses of what it is that makes us tick.

Research into the biological basis of interval timing usually starts from what is known as the 鈥減acemaker-accumulator鈥� model. This proposes that the brain has an internal pacemaker of some kind, which emits regular pulses that are temporarily stored in an accumulator. When we need an estimate of how much time has passed 鈥� how long we鈥檝e been waiting for a bus, say, or whether that pot of tea is likely to be ready 鈥� we simply access the contents of the accumulator.

The inner stopwatch

The pacemaker-accumulator model is good at predicting and explaining how people perform in behavioural experiments in which they are asked, for example, to judge the duration of a tone or a flashing light. But as brain research has progressed, the model has been criticised as too simplistic. In particular, it says nothing about the identity of the pacemaker, nor which parts of the brain are involved in interval timing.

Over the past few years, neuroscientists have started probing the brain鈥檚 timing mechanisms using measurements of electrical activity and imaging techniques such as fMRI. They have also looked at people whose time perception has been disturbed by disease or brain damage. The result is a more complex model of interval timing called 鈥渃oincidence detection鈥�.

Last year, Warren Meck and Catalin Buhusi of Duke University in Durham, North Carolina, brought the results together (). They suggest that the hub of the interval-timing system is a region of the brain called the striatum, part of the basal ganglia. But it is not as simple as saying that the striatum is the brain鈥檚 pacemaker. Instead, they say, it monitors activity in other areas of the brain including the frontal cortex. As neurons in these brain regions go about their business, coordinating movement, attention, memory and so on, they produce waves of electrical excitation that are detected by the striatum and integrated into an estimate of how much time has passed.

The coincidence-detection model is still work in progress, but one thing that is becoming clear is just how much flexibility there is in the way we perceive the passage of time. That should probably come as no surprise 鈥� it鈥檚 common knowledge that time perception can be altered by drugs and different mental states such as depression, arousal and meditation. And as everyone knows, time flies when you鈥檙e absorbed in a task and drags when you鈥檙e bored. But now researchers are beginning to understand the reasons for these subjective distortions of time. Some even think it will one day be possible to manipulate our perception of time whenever we feel like it.

鈥淵oung people are trying to get in touch with their inner tortoise鈥�

So how might we alter our experience of time? The first option might be to manipulate brain chemistry, in particular the dopamine system. Patients with disorders of this system, such as Parkinson鈥檚 disease, Huntington鈥檚 or schizophrenia, also suffer disturbances in their perception of time. It turns out this is because their neurochemistry 鈥� specifically their dopamine system 鈥� somehow alters the speed of their subjective internal clock. 鈥淪chizophrenics have too much dopamine activity in the brain so their clock is so fast that it feels like the whole world is crazy,鈥� says Meck. 鈥淚f you block dopamine receptors with drugs you can bring the speed of their internal clock back to an acceptable level.鈥�

Recreational drugs that affect the dopamine system can also alter our perception of time. Stimulants such as cocaine, caffeine and nicotine make time pass faster, while sedatives such as Valium and cannabis slow it down.

So would the dopamine system be a place to start the hunt for designer drugs that alter our perception of time? Perhaps. The pharmacological knowledge is certainly there, says Meck. 鈥淚 think it would be possible to develop a boutique drug that did the same but without the addictive properties. I鈥檓 sure it could be done if the market was there.鈥� But while we wait for the arrival of the ultimate 鈥渃hill pill鈥�, what about more natural ways of controlling our internal clock?

When it comes to using the power of the mind to control time perception, one of the most important factors is the attention we pay to the passage of time. According to Meck, although we are rarely conscious of time passing, we keep a subconscious check on our interval-timing system and every now and again consciously access the information. This sporadic attention keeps our perception of the passage of time chugging along nicely.

When time flies

But if for some reason we disengage attention from the clock, our sense of time can go astray. This accounts for the old adage that 鈥渢ime flies when you鈥檙e having fun鈥�, or more accurately, 鈥渢ime flies when you are focusing on something other than the passage of time鈥�. It is equally possible to push the clock in the other direction. At last year鈥檚 meeting of the Society for Neuroscience in Washington DC, the Dalai Lama gave a talk to the assembled neuroscientists on how time seems to slow down during meditation, as you focus away from the internal clock. Yet when you surface from meditation, he said, you think more time has passed than actually has. This is uncannily like being in the zone.

Though these effects seem paradoxical, a number of experiments show how the attention we pay 鈥� or don鈥檛 pay 鈥� to the passage of time affects our perception of it. As it turns out, the answer depends on whether you are thinking about time 鈥渋n the moment鈥� or after the event.

The standard way of measuring the subjective passage of time, prospective timing, is to make you aware that time is important before you do a task. So, for example, you鈥檙e told: 鈥淚鈥檓 going to play a tone, tell me how long it lasts.鈥� This is typical of lab experiments on interval timing, but is somewhat artificial. After all, it鈥檚 not often that you consciously time something in the real world. And so some psychologists, including Wearden, have started experimenting with two other measurements of the subjective passage of time.

The first of these is 鈥渞etrospective timing鈥�, in which you make a post-hoc estimate of how long something lasted without being primed beforehand. So, for example, how long have you been reading this magazine? In the second, which Wearden calls 鈥減assage-of-time judgements鈥�, you assess how quickly time seems to have gone by after spending some time on an activity, compared with normal.

For the past year or so, Wearden has been experimenting with these two measures of the passage of time. In the 鈥淎rmageddon experiments鈥�, he divided volunteers into two groups. One group watched 9 minutes of the movie Armageddon while the other sat in a waiting room for the same length of time. As expected, when they were asked to make a passage-of-time judgement, the Armageddon group reported that time seemed to have gone more quickly than usual, while the group who sat in the waiting room thought that time had dragged. But when he asked the two groups to make a retrospective judgement of how long they thought the task had lasted, the results were the opposite. Despite feeling that time had flown, the Armageddon group judged the time period as about 10 per cent longer than the waiting group. Surprisingly, both groups estimated that the time was less than the actual 9 minutes.

鈥淩ecreational drugs can do weird things to the passage of time鈥�

The explanation, says Wearden, is that the subjects made their second estimate based on how much information they had processed 鈥� or their memory of the number of events that happened 鈥� during the experiment. 鈥淚n the waiting room there was not much happening and time passed slowly,鈥� he says. 鈥淏ut looking back at it, the period was quicker because it didn鈥檛 contain any events. The Armageddon period went quickly when you were in it but retrospectively you use the amount of things you remember as a judgement of time and so it seemed long. It鈥檚 a kind of paradox.鈥�

It is early days, and very few experiments like this have been done, but these kinds of studies could help unravel some of the mysteries of time perception, such as why some elderly people feel that the days seem to drag, but that the years flash by. It could be that these people have less to do and so spend more of the day paying attention to the passage of time. But when they look back, their brains haven鈥檛 processed much information, and so they judge that time passed quickly.

Wearden points out that these experiments haven鈥檛 been done in elderly people, and there may be other explanations for their distorted perception of time. Memory and IQ are known to decline with age, for example, which could have an impact on perception of time. 鈥淚n a way we鈥檙e kind of theorising in a vacuum,鈥� says Wearden. 鈥淲e think we know what the problems are, but there is no study that explains what old people complain about.鈥�

Meanwhile, for anyone looking to adjust their pace of life, the results of Wearden鈥檚 Armageddon experiments raise something of a dilemma. You can stretch your perception of time, but only if you鈥檙e prepared to spend it in the equivalent of a waiting room. Perhaps the best option is to just accept the hectic pace of modern life, but make a serious effort to spend at least some of your time doing nothing much.

That might sound like common sense. But according to social psychologist Robert Levine of California State University in Fresno, it is common sense that鈥檚 well worth remembering. 鈥淭ime is our most valuable possession,鈥� he says. 鈥淯ntil the biomedical people can make us live forever, the closest thing we have is to stretch the moment.鈥�

So taking a decade to learn how to get into the zone could be a great investment. But let鈥檚 face it, most of us simply don鈥檛 have the time.