Tag Archives: time

Cosmology, Particle Soup

Spacetime Without the Time

anti-de-sitter-spaceSince they were first dreamed up explanations of the very small (quantum mechanics) and the very large (general relativity) have both been highly successful at describing their respective spheres of influence. Yet, these two descriptions of our physical universe are not compatible, particularly when it comes to describing gravity. Indeed, physicists and theorists have struggled for decades to unite these two frameworks. Many agree that we need a new theory (of everything).

One new idea, from theorist Erik Verlinde of the University of Amsterdam, proposes that time is an emergent construct (it’s not a fundamental building block) and that dark matter is an illusion.

From Quanta:

Theoretical physicists striving to unify quantum mechanics and general relativity into an all-encompassing theory of quantum gravity face what’s called the “problem of time.”

In quantum mechanics, time is universal and absolute; its steady ticks dictate the evolving entanglements between particles. But in general relativity (Albert Einstein’s theory of gravity), time is relative and dynamical, a dimension that’s inextricably interwoven with directions x, y and z into a four-dimensional “space-time” fabric. The fabric warps under the weight of matter, causing nearby stuff to fall toward it (this is gravity), and slowing the passage of time relative to clocks far away. Or hop in a rocket and use fuel rather than gravity to accelerate through space, and time dilates; you age less than someone who stayed at home.

Unifying quantum mechanics and general relativity requires reconciling their absolute and relative notions of time. Recently, a promising burst of research on quantum gravity has provided an outline of what the reconciliation might look like — as well as insights on the true nature of time.

As I described in an article this week on a new theoretical attempt to explain away dark matter, many leading physicists now consider space-time and gravity to be “emergent” phenomena: Bendy, curvy space-time and the matter within it are a hologram that arises out of a network of entangled qubits (quantum bits of information), much as the three-dimensional environment of a computer game is encoded in the classical bits on a silicon chip. “I think we now understand that space-time really is just a geometrical representation of the entanglement structure of these underlying quantum systems,” said Mark Van Raamsdonk, a theoretical physicist at the University of British Columbia.

Researchers have worked out the math showing how the hologram arises in toy universes that possess a fisheye space-time geometry known as “anti-de Sitter” (AdS) space. In these warped worlds, spatial increments get shorter and shorter as you move out from the center. Eventually, the spatial dimension extending from the center shrinks to nothing, hitting a boundary. The existence of this boundary — which has one fewer spatial dimension than the interior space-time, or “bulk” — aids calculations by providing a rigid stage on which to model the entangled qubits that project the hologram within. “Inside the bulk, time starts bending and curving with the space in dramatic ways,” said Brian Swingle of Harvard and Brandeis universities. “We have an understanding of how to describe that in terms of the ‘sludge’ on the boundary,” he added, referring to the entangled qubits.

The states of the qubits evolve according to universal time as if executing steps in a computer code, giving rise to warped, relativistic time in the bulk of the AdS space. The only thing is, that’s not quite how it works in our universe.

Here, the space-time fabric has a “de Sitter” geometry, stretching as you look into the distance. The fabric stretches until the universe hits a very different sort of boundary from the one in AdS space: the end of time. At that point, in an event known as “heat death,” space-time will have stretched so much that everything in it will become causally disconnected from everything else, such that no signals can ever again travel between them. The familiar notion of time breaks down. From then on, nothing happens.

On the timeless boundary of our space-time bubble, the entanglements linking together qubits (and encoding the universe’s dynamical interior) would presumably remain intact, since these quantum correlations do not require that signals be sent back and forth. But the state of the qubits must be static and timeless. This line of reasoning suggests that somehow, just as the qubits on the boundary of AdS space give rise to an interior with one extra spatial dimension, qubits on the timeless boundary of de Sitter space must give rise to a universe with time — dynamical time, in particular. Researchers haven’t yet figured out how to do these calculations. “In de Sitter space,” Swingle said, “we don’t have a good idea for how to understand the emergence of time.”

Read the entire article here.

Image: Image of (1 + 1)-dimensional anti-de Sitter space embedded in flat (1 + 2)-dimensional space. The t1- and t2-axes lie in the plane of rotational symmetry, and the x1-axis is normal to that plane. The embedded surface contains closed timelike curves circling the x1 axis, though these can be eliminated by “unrolling” the embedding (more precisely, by taking the universal cover). Courtesy: Krishnavedala. Wikipedia. Creative Commons Attribution-Share Alike 3.0.

Idea Soup, Technica

Your Current Dystopian Nightmare: In Just One Click

Amazon was supposed to give you back precious time by making shopping and spending painlessly simple. Apps on your smartphone were supposed to do the same for all manner of re-tooled on-demand services. What wonderful time-saving inventions! So, now you can live in the moment and make use of all this extra free time. It’s your time now. You’ve won it back and no one can take it away.

And, what do you spend this newly earned free time doing? Well, you sit at home in your isolated cocoon, you shop for more things online, you download some more great apps that promise to bring even greater convenience, you interact less with real humans, and, best of all, you spend more time working. Welcome to your new dystopian nightmare, and it’s happening right now. Click.

From Medium:

Angel the concierge stands behind a lobby desk at a luxe apartment building in downtown San Francisco, and describes the residents of this imperial, 37-story tower. “Ubers, Squares, a few Twitters,” she says. “A lot of work-from-homers.”

And by late afternoon on a Tuesday, they’re striding into the lobby at a just-get-me-home-goddammit clip, some with laptop bags slung over their shoulders, others carrying swank leather satchels. At the same time a second, temporary population streams into the building: the app-based meal delivery people hoisting thermal carrier bags and sacks. Green means Sprig. A huge M means Munchery. Down in the basement, Amazon Prime delivery people check in packages with the porter. The Instacart groceries are plunked straight into a walk-in fridge.

This is a familiar scene. Five months ago I moved into a spartan apartment a few blocks away, where dozens of startups and thousands of tech workers live. Outside my building there’s always a phalanx of befuddled delivery guys who seem relieved when you walk out, so they can get in. Inside, the place is stuffed with the goodies they bring: Amazon Prime boxes sitting outside doors, evidence of the tangible, quotidian needs that are being serviced by the web. The humans who live there, though, I mostly never see. And even when I do, there seems to be a tacit agreement among residents to not talk to one another. I floated a few “hi’s” in the elevator when I first moved in, but in return I got the monosyllabic, no-eye-contact mumble. It was clear: Lady, this is not that kind of building.

Back in the elevator in the 37-story tower, the messengers do talk, one tells me. They end up asking each other which apps they work for: Postmates. Seamless. EAT24. GrubHub. Safeway.com. A woman hauling two Whole Foods sacks reads the concierge an apartment number off her smartphone, along with the resident’s directions: “Please deliver to my door.”

“They have a nice kitchen up there,” Angel says. The apartments rent for as much as $5,000 a month for a one-bedroom. “But so much, so much food comes in. Between 4 and 8 o’clock, they’re on fire.”

I start to walk toward home. En route, I pass an EAT24 ad on a bus stop shelter, and a little further down the street, a Dungeons & Dragons–type dude opens the locked lobby door of yet another glass-box residential building for a Sprig deliveryman:

“You’re…”

“Jonathan?”

“Sweet,” Dungeons & Dragons says, grabbing the bag of food. The door clanks behind him.

And that’s when I realized: the on-demand world isn’t about sharing at all. It’s about being served. This is an economy of shut-ins.

In 1998, Carnegie Mellon researchers warned that the internet could make us into hermits. They released a study monitoring the social behavior of 169 people making their first forays online. The web-surfers started talking less with family and friends, and grew more isolated and depressed. “We were surprised to find that what is a social technology has such anti-social consequences,” said one of the researchers at the time. “And these are the same people who, when asked, describe the Internet as a positive thing.”

We’re now deep into the bombastic buildout of the on-demand economy— with investment in the apps, platforms and services surging exponentially. Right now Americans buy nearly eight percent of all their retail goods online, though that seems a wild underestimate in the most congested, wired, time-strapped urban centers.

Many services promote themselves as life-expanding?—?there to free up your time so you can spend it connecting with the people you care about, not standing at the post office with strangers. Rinse’s ad shows a couple chilling at a park, their laundry being washed by someone, somewhere beyond the picture’s frame. But plenty of the delivery companies are brutally honest that, actually, they never want you to leave home at all.

GrubHub’s advertising banks on us secretly never wanting to talk to a human again: “Everything great about eating, combined with everything great about not talking to people.” DoorDash, another food delivery service, goes for the all-caps, batshit extreme:

“NEVER LEAVE HOME AGAIN.”

Katherine van Ekert isn’t a shut-in, exactly, but there are only two things she ever has to run errands for any more: trash bags and saline solution. For those, she must leave her San Francisco apartment and walk two blocks to the drug store, “so woe is my life,” she tells me. (She realizes her dry humor about #firstworldproblems may not translate, and clarifies later: “Honestly, this is all tongue in cheek. We’re not spoiled brats.”) Everything else is done by app. Her husband’s office contracts with Washio. Groceries come from Instacart. “I live on Amazon,” she says, buying everything from curry leaves to a jogging suit for her dog, complete with hoodie.

She’s so partial to these services, in fact, that she’s running one of her own: A veterinarian by trade, she’s a co-founder of VetPronto, which sends an on-call vet to your house. It’s one of a half-dozen on-demand services in the current batch at Y Combinator, the startup factory, including a marijuana delivery app called Meadow (“You laugh, but they’re going to be rich,” she says). She took a look at her current clients?—?they skew late 20s to late 30s, and work in high-paying jobs: “The kinds of people who use a lot of on demand services and hang out on Yelp a lot ?”

Basically, people a lot like herself. That’s the common wisdom: the apps are created by the urban young for the needs of urban young. The potential of delivery with a swipe of the finger is exciting for van Ekert, who grew up without such services in Sydney and recently arrived in wired San Francisco. “I’m just milking this city for all it’s worth,” she says. “I was talking to my father on Skype the other day. He asked, ‘Don’t you miss a casual stroll to the shop?’ Everything we do now is time-limited, and you do everything with intention. There’s not time to stroll anywhere.”

Suddenly, for people like van Ekert, the end of chores is here. After hours, you’re free from dirty laundry and dishes. (TaskRabbit’s ad rolls by me on a bus: “Buy yourself time?—?literally.”)

So here’s the big question. What does she, or you, or any of us do with all this time we’re buying? Binge on Netflix shows? Go for a run? Van Ekert’s answer: “It’s more to dedicate more time to working.”

Read the entire story here.

Idea Soup

The Spacetime Discontinuum

Einstein transformed our notions of the universe, teaching us, amongst other things, that time is relative to the velocity of the observer. While he had in mind no less than the entire cosmos when constructing his elegant theories, he failed to consider relativity in the home and workplace, and specifically how women and men experience time differently.

From the WSJ:

Several years ago, while observing a parenting group in Minnesota, I was struck by a confession one of the women made to her peers: She didn’t really care that her husband did the dishes after dinner. Sure, it was swell of him, and she had friends whose husbands did less. But what she really wanted, at that point in her day, was for her husband to volunteer to put the kids to bed. She would have been glad to sit in the kitchen on her own for a few minutes with the water running and her mind wandering. Another woman chimed in: “Totally. The dishes don’t talk back to you.”

According to the American Time Use Survey—which asks thousands of Americans annually to chronicle how they spend their days—men and women now work roughly the same number of hours a week (though men work more paid hours, and women more unpaid). Given this balanced ledger, one might guess that all would finally be quiet on the domestic front—that women would finally have stopped wondering how they, rather than their husbands, got suckered into such a heavy load. But they haven’t. The question is: Why?

Part of the problem is that averages treat all data as if they’re the same and therefore combinable, which often results in a kind of absurdity. On average, human beings have half an Adam’s apple, but no one thinks to lump men and women together this way. Similarly, we should not assume that men and women’s working hours are the same in kind. The fact is, men and women experience their time very differently.

For starters, not all work is created equal. An hour spent on one kind of task is not necessarily the equivalent of an hour spent on another. Take child care, a task to which mothers devote far more hours than dads. It creates much more stress in women than other forms of housework. In “Alone Together” (2007), a comprehensive look at the state of American marriage, the authors found that if women believe child care is unevenly divided in their homes, this imbalance is much more likely to affect their marital happiness than a perceived imbalance in, say, vacuuming.

Or consider night duty. Sustained sleep deprivation, as we know, consigns people to their own special league of misery. But it’s generally mothers, rather than fathers, who are halfway down the loonytown freeway to hysterical exhaustion, at least in the early years of parenting. According to the American Time Use Survey, women in dual-earner couples are three times more likely to report interrupted sleep if they have a child under the age of 1, and stay-at-home mothers are six times as likely to get up with their children as are stay-at-home fathers.

Funny: I once sat on a panel with Adam Mansbach, the author of the best-selling parody “Go the F— to Sleep.” At one point in the discussion, he conceded that his partner put his child to bed most nights. He may have written a book about the tyranny of toddlers at bedtime, but in his house, it was mainly Mom’s problem.

Complicating matters, mothers assume a disproportionate number of time-sensitive domestic tasks, whether it’s getting their toddlers dressed for school or their 12-year-olds off to swim practice. Their daily routine is speckled with what sociologists Annette Lareau and Elliot Weininger call “pressure points,” or nonnegotiable demands that make their lives, as the authors put it, “more frenetic.”

These deadlines have unintended consequences. They force women to search for wormholes in the time-space continuum simply to accomplish all the things that they need to do. In 2011, the sociologists Shira Offer and Barbara Schneider found that mothers spend, on average, 10 extra hours a week multitasking than do fathers “and that these additional hours are mainly related to time spent on housework and child care.”

When fathers spend time at home, on the other hand, it reduces their odds of multitasking by over 30%. Which may explain why, a few years ago, researchers from UCLA found that a father in a room by himself was the “person-space configuration observed most frequently” in their close study of 32 families at home. It may also explain why many fathers manage to finish the Sunday paper while their wives do not—they’re not constantly getting up to refill bowls of Cheerios.

Being compelled to divide and subdivide your time doesn’t just compromise your productivity and lead to garden-variety discombobulation. It also creates a feeling of urgency—a sense that no matter how tranquil the moment, no matter how unpressured the circumstances, there’s always a pot somewhere that’s about to boil over.

Read the entire essay here.

Idea Soup

Innovation Before Its Time

Product driven companies, inventors from all backgrounds and market researchers have long studied how some innovations take off while others fizzle. So, why do some innovations gain traction? Given two similar but competing inventions, what factors lead to one eclipsing the other? Why do some pioneering ideas and inventions fail only to succeed from a different instigator years, sometimes decades, later? Answers to these questions would undoubtedly make many inventors household names, but as is the case in most human endeavors, the process of innovation is murky and more of an art than a science.

Author and columnist Matt Ridley offers some possible answers to the conundrum.

[div class=attrib]From the Wall Street Journal:[end-div]

Bill Moggridge, who invented the laptop computer in 1982, died last week. His idea of using a hinge to attach a screen to a keyboard certainly caught on big, even if the first model was heavy, pricey and equipped with just 340 kilobytes of memory. But if Mr. Moggridge had never lived, there is little doubt that somebody else would have come up with the idea.

The phenomenon of multiple discovery is well known in science. Innovations famously occur to different people in different places at the same time. Whether it is calculus (Newton and Leibniz), or the planet Neptune (Adams and Le Verrier), or the theory of natural selection (Darwin and Wallace), or the light bulb (Edison, Swan and others), the history of science is littered with disputes over bragging rights caused by acts of simultaneous discovery.

As Kevin Kelly argues in his book “What Technology Wants,” there is an inexorability about technological evolution, expressed in multiple discovery, that makes it look as if technological innovation is an autonomous process with us as its victims rather than its directors.

Yet some inventions seem to have occurred to nobody until very late. The wheeled suitcase is arguably such a, well, case. Bernard Sadow applied for a patent on wheeled baggage in 1970, after a Eureka moment when he was lugging his heavy bags through an airport while a local worker effortlessly pushed a large cart past. You might conclude that Mr. Sadow was decades late. There was little to stop his father or grandfather from putting wheels on bags.

Mr. Sadow’s bags ran on four wheels, dragged on a lead like a dog. Seventeen years later a Northwest Airlines pilot, Robert Plath, invented the idea of two wheels on a suitcase held vertically, plus a telescopic handle to pull it with. This “Rollaboard,” now ubiquitous, also feels as if it could have been invented much earlier.

Or take the can opener, invented in the 1850s, eight decades after the can. Early 19th-century soldiers and explorers had to make do with stabbing bayonets into food cans. “Why doesn’t somebody come up with a wheeled cutter?” they must have muttered (or not) as they wrenched open the cans.

Perhaps there’s something that could be around today but hasn’t been invented and that will seem obvious to future generations. Or perhaps not. It’s highly unlikely that brilliant inventions are lying on the sidewalk ignored by the millions of entrepreneurs falling over each other to innovate. Plenty of terrible ideas are tried every day.

Understanding why inventions take so long may require mentally revisiting a long-ago time. For a poorly paid Napoleonic soldier who already carried a decent bayonet, adding a can opener to his limited kitbag was probably a waste of money and space. Indeed, going back to wheeled bags, if you consider the abundance of luggage porters with carts in the 1960s, the ease of curbside drop-offs at much smaller airports and the heavy iron casters then available, 1970 seems about the right date for the first invention of rolling luggage.

[div class=attrib]Read the entire article following the jump.[end-div]

[div class]Image: Joseph Swan, inventor of the incandescent light bulb, which was first publicly demonstrated on 18 December 1878. Courtesy of Wikipedia.[end-div]

Idea Soup

Time Flows Uphill

Many people in industrialized countries often describe time as flowing like a river: it flows back into the past, and it flows forward into the future. Of course, for bored workers time sometimes stands still, while for kids on summer vacation time flows all too quickly. And, for many people over, say the age of forty, days often drag, but the years fly by.

For some, time flows uphill, and it flows downhill.

[div class=attrib]From New Scientist:[end-div]

“HERE and now”, “Back in the 1950s”, “Going forward”… Western languages are full of spatial metaphors for time, and whether you are, say, British, French or German, you no doubt think of the past as behind you and the future as stretching out ahead. Time is a straight line that runs through your body.

Once thought to be universal, this “embodied cognition of time” is in fact strictly cultural. Over the past decade, encounters with various remote tribal societies have revealed a rich diversity of the ways in which humans relate to time (see “Attitudes across the latitudes”). The latest, coming from the Yupno people of Papua New Guinea, is perhaps the most remarkable. Time for the Yupno flows uphill and is not even linear.

Rafael Núñez of the University of California, San Diego, led his team into the Finisterre mountain range of north-east Papua New Guinea to study the Yupno living in the village of Gua. There are no roads in this remote region. The Yupno have no electricity or even domestic animals to work the land. They live with very little contact with the western world.

Núñez and his colleagues noticed that the tribespeople made spontaneous gestures when speaking about the past, present and future. They filmed and analysed the gestures and found that for the Yupno the past is always downhill, in the direction of the mouth of the local river. The future, meanwhile, is towards the river’s source, which lies uphill from Gua.

This was true regardless of the direction they were facing. For instance, if they were facing downhill when talking about the future, a person would gesture backwards up the slope. But when they turned around to face uphill, they pointed forwards.

Núñez thinks the explanation is historical. The Yupno’s ancestors arrived by sea and climbed up the 2500-metre-high mountain valley, so lowlands may represent the past, and time flows uphill.

But the most unusual aspect of the Yupno timeline is its shape. The village of Gua, the river’s source and its mouth do not lie in a straight line, so the timeline is kinked. “This is the first time ever that a culture has been documented to have everyday notions of time anchored in topographic properties,” says Núñez.

Within the dark confines of their homes, geographical landmarks disappear and the timeline appears to straighten out somewhat. The Yupno always point towards the doorway when talking about the past, and away from the door to indicate the future, regardless of their home’s orientation. That could be because entrances are always raised, says Núñez. You have to climb down – towards the past – to leave the house, so each home has its own timeline.

[div class=attrib]Read the entire article following the jump.[end-div]

[div class=attrib]Image: The Persistence of Memory, by Salvador Dalí. Courtesy of Salvador Dalí, Gala-Salvador Dalí Foundation / Artists Rights Society (ARS), Museum of Modern Art New York / Wikipedia.[end-div]

Idea Soup

Our Perception of Time

[div class=attrib]From Evolutionary Philosophy:[end-div]

We have learned to see time as if it appears in chunks – minutes, hours, days, and years. But if time comes in chunks how do we experience past memories in the present? How does the previous moment’s chunk of time connect to the chunk of the present moment?

Wait a minute. It will take an hour. He is five years old. These are all sentences that contain expressions of units of time. We are all tremendously comfortable with the idea that time comes in discrete units – but does it? William James and Charles Sanders Peirce thought not.

If moments of time were truly discrete, separate units lined up like dominoes in a row, how would it be possible to have a memory of a past event? What connects the present moment to all the past moments that have already gone by?

One answer to the question is to suppose the existence of a transcendental self. That means some self that exists over and above our experience and can connect all the moments together for us. Imagine moments in time that stick together like boxcars of a train. If you are in one boxcar – i.e. inside the present moment – how could you possibly know anything about the boxcar behind you – i.e. the moment past? The only way would be to see from outside of your boxcar – you would at least stick your head out of the window to see the boxcar behind you.

If the boxcar represents your experience of the present moment then we are saying that you would have to leave the present moment at least a little bit to be able to see what happened in the moment behind you. How can you leave the present moment? Where do you go if you leave your experience of the present moment? Where is the space that you exist in when you are outside of your experience? It would have to be a space that transcended your experience – a transcendental space outside of reality as we experience it. It would be a supernatural space and the part of you that existed in that space would be a supernatural extra-experiential you.

For those who had been raised in a Christian context this would not be so hard to except because this extra-experiential you would sound a great deal like the soul. In fact Immanuel Kant who first articulated the idea of a transcendental self was through his philosophy actively trying to reserve space for the human soul in an intellectual atmosphere that he saw as excessively materialistic.

William James and Charles Sanders Peirce believed in unity and therefore they could not accept the idea of a transcendental ego that would exist in some transcendent realm. In some of their thinking they were anticipating the later developments of quantum theory and non-locality.

William James described who we appear to travel through a river of time – and like all rivers the river ahead of us already exists before we arrive there. In the same way the future already exists now. Not in a pre-determined sense but at least as some potentiality. As we arrive at the future moment our arrival marks the passage from the fluid form that we call future to the definitive solid form that we experience as the past. We do not create time by passing through it; we simply freeze it in its tracks.

[div class=attrib]Read the entire article after the jump.[end-div]

[div class=attrib]Image courtesy of Google search.[end-div]

BigBang

First Ever Demonstration of Time Cloaking

[div class=attrib]From the Physics arXiv for Technology Review:[end-div]

Physicists have created a “hole in time” using the temporal equivalent of an invisibility cloak.

Invisibility cloaks are the result of physicists’ newfound ability to distort electromagnetic fields in extreme ways. The idea is steer light around a volume of space so that anything inside this region is essentially invisible.

The effect has generated huge interest. The first invisibility cloaks worked only at microwave frequencies but in only a few years, physicists have found ways to create cloaks that work for visible light, for sound and for ocean waves. They’ve even designed illusion cloaks that can make one object look like another.

Today, Moti Fridman and buddies, at Cornell University in Ithaca, go a step further. These guys have designed and built a cloak that hides events in time.

Time cloaking is possible because of a kind of duality between space and time in electromagnetic theory. In particular, the diffraction of a beam of light in space is mathematically equivalent to the temporal propagation of light through a dispersive medium. In other words, diffraction and dispersion are symmetric in spacetime.

That immediately leads to an interesting idea. Just as its easy to make a lens that focuses light in space using diffraction, so it is possible to use dispersion to make a lens that focuses in time.

Such a time-lens can be made using an electro-optic modulator, for example, and has a variety of familiar properties. “This time-lens can, for example, magnify or compress in time,” say Fridman and co.

This magnifying and compressing in time is important.

The trick to building a temporal cloak is to place two time-lenses in series and then send a beam of light through them. The first compresses the light in time while the second decompresses it again.

But this leaves a gap. For short period, there is a kind of hole in time in which any event is unrecorded.

So to an observer, the light coming out of the second time-lens appears undistorted, as if no event has occurred.

In effect, the space between the two lenses is a kind of spatio-temporal cloak that deletes changes that occur in short periods of time.

[div class=attrib]More from theSource here.[end-div]

[div class=attrib]Original paper from arXiv.org here.[end-div]

BigBang

Why Does Time Fly?

[div class=attrib]From Scientific American:[end-div]

Everybody knows that the passage of time is not constant. Moments of terror or elation can stretch a clock tick to what seems like a life time. Yet, we do not know how the brain “constructs” the experience of subjective time. Would it not be important to know so we can find ways to make moments last, or pass by, more quickly?

A recent study by van Wassenhove and colleagues is beginning to shed some light on this problem. This group used a simple experimental set up to measure the “subjective” experience of time. They found that people accurately judge whether a dot appears on the screen for shorter, longer or the same amount of time as another dot. However, when the dot increases in size so as to appear to be moving toward the individual — i.e. the dot is “looming” — something strange happens. People overestimate the time that the dot lasted on the screen.  This overestimation does not happen when the dot seems to move away.  Thus, the overestimation is not simply a function of motion. Van Wassenhove and colleagues conducted this experiment during functional magnetic resonance imaging, which enabled them to examine how the brain reacted differently to looming and receding.

The brain imaging data revealed two main findings. First, structures in the middle of the brain were more active during the looming condition. These brain areas are also known to activate in experiments that involve the comparison of self-judgments to the judgments of others, or when an experimenter does not tell the subject what to do. In both cases, the prevailing idea is that the brain is busy wondering about itself, its ongoing plans and activities, and relating oneself to the rest of the world.

Read more from the original study here.

[div class=attrib]More from theSource here.[end-div]

[div class=attrib]Image courtesy of Sawayasu Tsuji.[end-div]