Almost everyone I’ve ever met is, in one way or another, fascinated by time. We intuitively understand it. We feel its passage—in the natural world, in the slow tread of the seasonal cycle outside our window; and in our professional lives, in the long, enervating meetings that bore many of us to tears. In our personal lives, we bear witness to its invisible presence in the quickening of our heartbeat, induced by the people and events that, by degrees, most move, thrill, and agitate us. And across our personal lifespan, we witness its passage, in the slow aging of our own bodies, and the corresponding growth of our children and the inevitable rise of the next generation. It is within this personal realm of temporal experience that clichés, like a world populated by policemen who seemingly just keep on getting younger, betoken our own individual temporal elapse—which, in time, will end.
But while we vividly experience time at a subjective (or phenomenological) level, there is nothing physical or concrete in the world—like stones or trees—that you or I can point to and thereby identify as time. We sense its presence: We anticipate the future, which is distinct from the present we inhabit, and our recollection of the past. But while intuitively apprehended, time is, paradoxically, unknowable. It amounts to "a familiar stranger,” as the great cosmologist and timesmith J.T. Frasier so evocatively put it.
This conundrum—the unknowability of that which we intuitively know so well—has exercised the keenest minds for millennia. Writing at the end of the fourth century of the Common Era, Saint Augustine, Bishop of Hippo, put this paradox in the following way in his autobiographical Confessions: “What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I do not know."
The commonplace view
A common view, perhaps the commonplace view, is that time is not in fact something that exists per se. Time, in this account, is a phantasm, a trick our minds somehow play on us, providing the wherewithal to understand that events don't all happen at once. A version of this view has been widely disseminated in cognitive science, by linguist George Lakoff and philosopher Mark Johnson, as part of their hugely influential conceptual metaphor theory.
Lakoff and Johnson claim that time exists for us not because it is something we actually perceive. Time, they suggest, may not, in fact, exist as a distinct entity, or a thing unto itself. We conceptualize and understand time, they say, because time is essentially a metaphorized version of events undergoing motion. When we say, Christmas is approaching, we are, in fact, recruiting knowledge relating to motion through space to understand the imminence of a temporal event: Christmas. In short, we must first understand space, and structure time in terms of motion events in space, before we can conceptualize time. Only then can we experience it.
But, time, from this perspective, is very much a second-class citizen. It is a cognitive achievement, rather than a phenomenological experience that is directly perceived. And it is parasitic on spatial experience—and not, in fact, a fundamental aspect of human cognition.
This explanation may be neat and, for many, highly appealing, but it has long troubled and preoccupied me, as attested by two books I've written on different aspects of this issue, The Structure of Time (2004), and Language and Time (2013). Time, like the more concrete sensory-motor realm of space, is intuitively a foundational domain of human experience, and indeed knowledge.
Language itself, in most, if not all the world’s languages, appears to reflect the primacy of space and time—many languages, including English, enshrine this distinction in the very fabric of their grammatical machinery, with, for instance, the bifurcation between nouns—which prototypically denote physical entities—and verbs—which prototypically denote actions that evolve through time.
Is our intuitive sense of the foundational nature of both space and time wrong? Is time in a profound sense less real than space? Or does the distinction between the two, in lived human experience, relate to a distinction in quality, rather than a distinction between something that is real (space) and something that is a useful, but nevertheless fictional, abstract construct (time)?
I want to examine what we now know about temporal experience, at different levels of representation and processing—the neurological, cognitive and linguistic levels. To begin, I ask, and answer, a fundamental question: Do we directly perceive time? And if so, what appears to influence our perception of it?
It’s only Tuesday
Consider the following, wonderful excerpt from my favorite satirical magazine, The Onion:
“Washington DC— After running a thousand errands, working hours of overtime, and being stuck in seemingly endless gridlock traffic commuting to and from their jobs, millions of Americans were disheartened to learn that it was, in fact, only Tuesday.
"Tuesday?" San Diego resident Doris Wagner said. "How in the hell is it still Tuesday?"
Tuesday's arrival stunned a nation still recovering from the nightmarish slog that was Monday, leaving some to wonder if the week was ever going to end, and others to ask what was taking Saturday so goddamn long.
"Ugh," said Wagner, echoing a national sense of frustration over it not even being Wednesday at the very least.
According to suddenly depressed sources, the feeling that this week may in fact last forever was further compounded by the thought of all the work left to be done tomorrow, the day after tomorrow, and, if Americans make it that far, possibly even Friday, for Christ's sake.
Fears that the week could actually be going backwards were also expressed. "Not only do Americans have most of Tuesday morning to contend with, but all of Tuesday afternoon and then Tuesday night," National Labor Relations Board spokesman David Prynn said. "If our calculations are correct, there is a chance we are in effect closer to last weekend than the one coming up."
Isolated attempts to make the day go faster, such as glancing at watches or clocks every other minute, compulsively checking e-mail, hiding in the office bathroom, fidgeting, or reading a boring magazine while sitting in the waiting room, have also proven unsuccessful, sources report.
The National Institutes of Standards and Technology, which oversees the official time of the United States, is flatly denying that it has slowed or otherwise tampered with Tuesday's progression.”
This excerpt captures the familiar feeling, for many, of the work week. We approach Monday with dread. The week brings crammed buses and trains, or the tortuous stop-start drive along congested roads to the office. At work, we have to contend with full email inboxes—messages, inevitably, all marked urgent—endless meetings, being patronized by superiors, dealing with bad-tempered colleagues, snatched lunches, and so on. And having navigated Monday, many of us will relate to the feeling of frustration that it’s still only Tuesday.
But this piece also reveals something else, something quite remarkable about our experience of time. Time can go faster, or slower; it can even stand still. And sometimes, it can even feel as if it is going backwards.
Time really does speed up, and slow down!
Is there hard evidence that time really can speed up, and slow down? Let’s look at some examples: Imagine the the drive to work on the first day of a new job. The journey might take, say, around 20 minutes. But as you pay attention to the details of the route, and follow with care the instructions from your GPS device, the journey most likely feels as if it lasts much longer. This is what psychologists refer to as "protracted duration"—time feels as if it’s going more slowly than normal. Then, after a couple of months in the job, one morning you’ll marvel that the car drove itself to work: You arrived, seemingly in no time at all, and can barely remember the details of the route. This is referred to as "temporal compression"—time feels as if it’s passing more quickly than normal.
Protracted duration and temporal compression are real phenomena. The social psychologist Michael Flaherty has documented subjects’ experiences of both, in his wonderful book: A Watched Pot.
In one interview, a young woman vividly describes her very real-experience of time slowing down during a car accident:
My first thought was, “Where did that car come from?” Then I said to myself, “Hit the brakes.”. . . I saw her look at me through the open window, and turn the wheel, hand over hand, toward the right. I also [noticed] that the car was a brown Olds. I heard the screeching sound from my tires and knew . . . that we were going to hit. . . I wondered what my parents were going to say, if they would be mad, where my boyfriend was, and most of all, would it hurt ... After it was over, I realized what a short time it was to think so many thoughts, but, while it was happening, there was more than enough time. It only took about 10 or 15 seconds for us to hit, but it certainly felt like 10 or 15 minutes.
The apparent slowing of time appears to arise in contexts when the subject is experiencing extreme emotions, as in a near-death experience like a car crash. Protracted duration also occurs when we’re unfamiliar with a new task, such as learning the drive to a new place of work. A third cause appears to be what might be dubbed empty intervals. In the following excerpt from Flaherty’s work, a survivor of a concentration camp during the Holocaust describes his experience of time while in captivity:
The days passed with a terrible, enervating, monotonous slowness, the tomorrows blending into weeks and the weeks blending into months. “We were about a year in Auschwitz,” says Menashe, “but in Auschwitz, one day—every day—was like 10 years.
Being imprisoned fails to give rise to significant or memorable events. On the contrary, in so-called empty intervals, one becomes preoccupied with self and situation, such that, compared to an event with a normal event contour, the interval feels longer than it otherwise is—at least as measured by a clock.
We can all relate to the expression: Time drags when you’re bored
In contrast, time seems to proceed more quickly in other situations: When the daily drive to work becomes routine, it flies by. This suggests that familiarity through repetition can lead to the opposite—time goes more quickly. Moreover, novel situations which are exciting, such as a dinner date with someone we find attractive, witty, and intelligent can lead to us losing ourselves, becoming absorbed in the event. Similarly, letting off steam by playing a new computer game can lead us to losing track of time, and time flying by. Situations such as these seem to go hand in hand with temporal compression.
Flaherty has argued that time appears to slow down in particular contexts when we are paying greater attention to self and the situations in which we find ourselves. In both near-death experiences and situations when we are bored, we experience a heightened focus on the self. And this leads us to process a greater amount of information, making it feel as if time is proceeding more slowly. In contrast, when our attention is not absorbed by self and situation—for instance in tasks that we can do standing on our heads—time feels, in retrospect, as if it’s zipped by.
Other research has confirmed that time proceeds more slowly in empty intervals, and speeds up when episodes are crammed with activity. In one study, participants were confined to a sensory isolation unit and instructed to estimate the time of day at various intervals throughout a 60-hour period. The results showed that without access to temporal cues, participants tended to underestimate the elapsed time, with the average subjective hour being judged at 1.12 hours in real time.
In another study, Michel Siffre, assuming the role of both experimenter and subject, and exhibiting remarkable dedication to science, confined himself to an underground cave. When he emerged after 58 days he underestimated the duration of his sojourn as having lasted only 33 days.
The perceived duration of shorter time intervals can also be distorted. In one study, participants watched a 30-second videotape of a bank robbery, full of activity and danger. They were later asked to estimate the duration of the event. The results showed that, on average, participants overestimated the event as having lasted 150 seconds—five times longer.
Just a trick of the imagination?
But is this all not just a trick of the imagination? Can time really fly, or drag by?
As it turns out, it seems that time really can. In the 1930s, a psychologist named Hudson Hoagland discovered, almost by accident, that how we experience time is closely related to bodily function. Hoagland’s wife was suffering from a fever and her high temperature appeared to be affecting her sense of time. With commendable detachment in the pursuit of scientific enquiry, he temporarily set aside his nursing duties, testing her as her fever varied in temperature. He observed that the higher the temperature, the more her perception of time appeared to speed up.
Hoagland had his wife estimate time’s passage by counting up to 60—a "subjective" minute—in which each count corresponded to what she felt to be a second. He found that at higher temperatures, his wife’s seconds became shorter, while they were longer at lower temperatures. For instance, at 98 degrees Fahrenheit, Hoagland’s wife judged a minute as corresponding to around 52 seconds. However, at 101 degrees Fahrenheit, she judged a minute to be equal to about 40 seconds. In other words, the higher the fever, the more Hoagland’s wife misjudged time’s passage: Her subjective minute got shorter.
Hoagland explored this observation further by subjecting students to temperatures of up to 65 degrees Celsius by placing heated helmets on their heads. (How times have changed: Experimental psychology professors today would far less readily obtain ethical approval for torturing their long-suffering grad students.) Hoagland found that an increase in body temperature could speed up our experience of time by as much as a remarkable 20%.
This finding has since been replicated using different stimulants—amphetamines,
nitrous dioxide ("laughing gas"), and even large quantities of very strong coffee appear to cause our experience of time to be overestimated—time actually goes by faster. In contrast, anything that depresses vital functioning appears to lead to time being perceived as going more slowly—we underestimate time’s passage. In one experiment, divers were submerged in the sea off the west coast of Wales in March, when sea temperatures are around 4 degrees Celsius—about the same as your average fridge. The divers were asked to count up to 60 seconds before and after the dive. While beforehand, their counting fairly accurately matched clock-time, afterward their counting was slower, with a subjective minute being judged as corresponding to around 70 seconds.
So what do these time dilation effects reveal?
Experiences like protracted duration and temporal compression are real-life time dilation effects. Time really can become distorted in terms of how we experience and live it. What this seems to reveal is that our experience of time is directly tied to the functioning of our bodies, as well as the types of situations in which we find ourselves. It arises internally, an experiential byproduct of how we interpret and process events. But if this is the case, then it calls into question Lakoff and Johnson’s claim that time is primarily created by conceptual metaphor—that it doesn’t exist as a thing unto itself.
So, where does this leave us? Is there a clock in the brain that enables us to perceive time? This is the issue which I address in my speculative Songs of the Sage science fiction books, review here.
