Author: Matt

The sound and the fury

Today’s article was going to be a pretty straightforward technological exposition. I was going to describe a procedure that can improve hearing in ways that conventional hearing aids cannot, mention some of the limitations and risks involved, and pretty much leave it at that. Then I got an email from a friend wondering if I was planning to cover the political issues cochlear implants raise for the Deaf community. Um…political issues? I hadn’t known there were any. But after a bit of research, I discovered that the controversy surrounding this procedure is at least as interesting as the procedure itself, which has been called everything from a miracle cure to genocide.

Can You Hear Me Now?

First, a bit of background. There are many different types and causes of deafness. Some kinds of hearing loss can be compensated for very adequately with just a bit of amplification—namely, a hearing aid. However, if there is a defect or damage in the inner ear, a hearing aid may do no good. Our perception of sound results from the vibrations of tiny hairs lining the cochlea, a spiral, fluid-filled organ in the inner ear. When the hairs move, the hair cells convert the movement into nerve impulses, which are then sent to the brain for decoding. If the vibrations never reach the cochlea, or if the hair cells themselves are damaged, no neural stimulation occurs and deafness results.

However, if most of the underlying nerve fibers themselves (and the neural pathways to the brain) are intact, they can be stimulated electrically, producing a sensation interpreted by the brain as sound. A cochlear implant places a series of electrodes inside the cochlea to do just that; a wire connects these electrodes to a small receiver with its antenna placed under the skin. Outside the skin, a device that looks somewhat like a hearing aid picks up sounds with a microphone, digitizes them in such a way that they produce meaningful signals for the electrodes, and transmits them via radio waves to the receiver. The net result is the perception of sounds picked up by the microphone, but because this apparatus completely bypasses the eardrum and middle ear, it’s really an artificial ear rather than a hearing aid. The technology was developed by Dr. Graeme Clark at the University of Melbourne in the 1960s and 1970s; the first implant was performed in 1978.

Although any number of technological innovations have occurred in the decades since, cochlear implants are still by no means perfect. They vary greatly in their effectiveness, depending on a large number of variables. And the effect they produce, while auditory in nature, is not identical to what would be experienced with a fully functional ear. In addition, patients with cochlear implants require months or years of training to associate their new perceptions with sounds as they are usually known. In the most successful cases, implant recipients can eventually understand someone talking on the phone—but there is no guarantee of that level of hearing. Still, tens of thousands of people around the world have received the implants, and the procedure is rapidly gaining in popularity.

You Will All Be Assimilated

To a hearing person such as myself, all this sounds very rosy and optimistic. Of course, the surgery is rather delicate and carries with it the usual risks associated with putting holes in one’s head; plus, the cost of the procedure and rehabilitative therapy is quite high. But these are not the primary concerns of the Deaf community. Although the controversy has diminished greatly in recent years, cochlear implants—particularly for children—were strongly opposed by many deaf people for some time because of a fear that they would destroy the Deaf culture in general and the use of sign language in particular.

On the surface, this argument may seem sort of silly to hearing persons. But the Deaf community has a unique culture and language that they rightly consider quite valuable; the thought of losing such a culture to technology is understandably offensive. One of the key beliefs of the Deaf community is that deafness is simply another perfectly valid way of life, not a problem that needs to be fixed. So the intimation that deafness is a “disease” for which cochlear implants are a “cure” smacks of assimilationism: “You must all be like us.” (The 2000 documentary film Sound and Fury examines the controversy over cochlear implants in detail as it follows members of two families through their decisions about whether or not to undergo the procedure.)

Even detractors of cochlear implants allow that this must be an individual decision, and that implants may be a reasonable choice for people who have lost hearing later in life (and who therefore may not have integrated themselves into the Deaf community). But when it comes to implants for children, the story is different. If a deaf child does not receive an implant, he or she is likely to learn sign language easily and adopt the Deaf culture. With an implant, the child is more likely to be treated as a hearing child. However, the imperfect nature of “hearing” provided by the implants may make it difficult to learn spoken English; meanwhile, because the parents have little incentive to raise the child as a deaf person, the child may never learn sign language. The result is that the child has less ability to communicate than if the implant had not been performed. In addition, if the child has partial hearing, the implant may eliminate any possibility of later using a conventional hearing aid by impeding normal functioning of the cochlea.

On the whole, decades of experience with cochlear implants in thousands of children have not borne out these worries, so resistance to implants in children is decreasing somewhat. Conventional wisdom holds that someone with a cochlear implant is still deaf, and many people with implants—children and adults alike—continue to learn and use sign language, participating actively in the Deaf culture. If cochlear implants, in a roundabout way, can promote both bilingualism and biculturalism, that may be their most compelling advantage.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on October 14, 2004.

Image credit: BruceBlaus [CC BY-SA 4.0], via Wikimedia Commons

Split-second thinking

The whole notion of time fascinates me endlessly—speaking metaphorically, of course. Numerous articles here at Interesting Thing of the Day have involved time or timekeeping in one form or another. In one of these articles, about analog clocks, I made what I thought was a commonsense and uncontroversial remark:

…time itself is continuous, not an infinite series of discrete steps…. Units like seconds, minutes, and hours are just a convenient, arbitrary fiction, after all—they don’t represent anything objectively real in the world.

A reader wrote in to suggest that I wasn’t up to date on my quantum physics, according to some theories of which time is indeed quantized, or fundamentally composed of very tiny but indivisible units.

At first, I had a hard time getting my head around this notion, and after considerable research…I still have a hard time getting my head around this notion. Although I try to keep generally abreast of the latest developments in the world of science, I can’t claim to do anything more than dabble in theoretical physics, and complex equations simply make my eyes glaze over. Nevertheless, it’s not only true that many scientists take the notion of quantized time for granted, there was also a fairly major uproar in the early 2000s when a young upstart from New Zealand published a paper that dared to challenge this notion with a theory that says, in effect, that there’s no such thing as an indivisible moment in time.

Second Thoughts

To understand what it would mean for time to be quantized, think of a unit of time, such as a second. You can divide that in half, getting two shorter periods of a half-second each. You can go much smaller, too, dividing a second into a thousand parts called milliseconds, a million parts called microseconds, a billion parts called nanoseconds, a trillion parts called picoseconds, and so on. A trillionth of a second is, to me, such an unimaginably short period of time that I’d be happy to consider it, for all practical purposes, indivisible—an “atom” of time, as it were. But that’s nothing. A trillionth of a second is a decimal point, 12 zeroes, and a 1. Some scientists say that meaningful distinctions in time can be made down to 10^–44 second, or 44 zeroes after the decimal point before you reach that 1. But the question is: how low can you go? Is there some point, some number of zeroes, beyond which time cannot be divided any further?

One of the fundamental notions of calculus, and of physics, is that one can determine a moving object’s exact position at some instant in time. That there should be such a thing as an “instant” is taken as a given. An instant effectively doesn’t have duration; that would imply that a moving object changes its position between the start of that instant and its end—in other words, that its position can’t be known precisely. However, seemingly it can, or at least that operational assumption has served calculus well all these centuries. But is the notion of an instant merely a convenient fiction, or does it in some sense represent reality?

Among scientists studying quantum theory, and particularly among those working on the quixotic task of unifying general relativity with quantum physics, the question of whether time is truly continuous or not is of particular interest. Some scientists say that, as far as general relativity goes, time is continuous, but that in order to create a Grand Unified Theory, we might have to accept that it can be treated as a succession of temporal quanta (or chronons), in much the same way that light can be treated as either a wave or a particle. Others say that time is not merely a fourth dimension, but is itself three-dimensional, so from our point of view time is continuous, but from a point of view that encompasses time’s other dimensions, it’s quantized.

But all kinds of mysterious things happen in the quantum realm. What about the macro world we’re all familiar with?

Time for a Kiwi

In 2003, a then-27-year-old student from New Zealand named Peter Lynds published a paper in the peer-reviewed journal Foundations of Physics Letters that caused a great deal of controversy. Lynds claimed, essentially, that the whole notion of an instant is flawed, because if there were such a thing, a moving object measured and observed at that instant would appear to be static, and thus indistinguishable from a genuinely static object measured at that same instant. Since the two measurements clearly represent objects with different states, Lynds argued, it must be the case that there really aren’t any instants, only intervals (though those intervals might be very tiny). If true, this means that a moving object’s position can only ever be approximated—whether at the macro level or at the quantum level. And for this very reason, most of Zeno’s paradoxes turn out not to be paradoxical after all. Lynds went on to claim that time doesn’t flow because flow presumes an ongoing series of instants, that there is no “now” as such, and that our perception of time is just an odd consequence of the way our brains are wired.

The term “snapshot” is frequently used to describe the instant of time at which an object’s position might be determined, but I think it actually helps to make Lynds’s point. If you’re taking a picture of something that’s moving, you need a fast shutter speed to “freeze” the action, and the faster your subject is moving, the faster the shutter speed has to be. But if you set your shutter to, say, 1/4000 of a second and the photograph shows an arrow in mid-flight, with no blurring to suggest motion, that still doesn’t mean the arrow didn’t cover any distance during that tiny portion of a second the shutter was open. Of course it did. It’s just that the distance was sufficiently small, given the resolution of the camera and the human eye, to create the illusion of being frozen. So even if your hypothetical “shutter speed” is a zillionth of a second long, so that your measurement appears to give an exact, fixed location, that, too, is merely an illusion. The object in fact occupies more than one position during that time. Nothing mysterious about that at all.

Instant Controversy

When I heard Lynds’s idea, I thought it made perfectly good sense, and what I couldn’t comprehend was how scientists claimed, with considerable fervor, that they either couldn’t understand it or thought it was wrong-headed. I confess that I have not followed the debate about Lynds’s paper very closely in the years since its publication, and that I can understand only part of what I’ve read. However, it seems to me that many criticisms tend to mention either or both of two facts. First, critics note that Lynds was uncredentialed—he only had six months of university study at the time, so who was he to gainsay PhDs with years of experience? And second, if he were correct, that would mean that calculus as we know it must be essentially wrong or at least incomplete. And we all know it’s right. Right?

As to the matter of Lynds’s erstwhile lack of an advanced degree, all I have to say is: if he’s correct, that doesn’t matter, and those who say otherwise take themselves, and their formal education, way too seriously. As for the supposed assault on calculus, well, Lynds implies that calculus is not exactly wrong so much as very slightly inaccurate. Calculus as it stands appears to be right, but then, so are Newton’s laws of physics. Except they aren’t always: Newtonian physics breaks down both at the quantum level and when objects approach the speed of light. It seems to me—and again, I’m speaking as a nonmathematician here—that the very same thing could be true in this case. Calculus can be right at one level, and the absence of quantized time can be right at another level.

Of course, those are not the only criticisms, and the debate between Lynds’s supporters and detractors has gone through so many rounds of rebuttals and rejoinders that I can no longer keep track of who thinks what. But on the whole, the debate has made me feel even more secure in my personal, nonscientific belief that time is continuous, and I’m not going to doubt that for one instant.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on July 21, 2006.

Image credit: Illymarry [CC BY-SA 4.0], via Wikimedia Commons

Hong Kong’s moving landmark

I have very fond memories of my first (and only, so far) visit to Hong Kong in 2007. I was extremely impressed by the architecture and scenery, and by the vibrant street life on display throughout its many neighborhoods. As a first-time visitor, I also appreciated how easy it was to navigate, and how technology was used to solve problems in novel ways.

I first got a sense of this when I passed through Immigration, and had my body temperature scanned remotely to see if I was running a fever (important for a region that was then dealing with avian flu). I was further impressed with Hong Kong’s technological prowess when I discovered I could purchase a stored-value transit pass, called an Octopus card, which I could not only use on trains, buses, and trams, but could also use to buy snacks from a convenience store or food from certain restaurants. I found out later that locals can also buy rings, watches, and even cell phones that contain the Octopus chip, enabling them to simply wave their hands (or phones) over the special card readers to make a purchase. That may all sound unimpressive nowadays, but it was pretty advanced for 2007, to say nothing of 1997, when it was introduced.

While all these things are wonderful, my favorite piece of technology that makes life easier for visitors (and residents of course) is the Central–Mid-Levels Escalator. Stretching from the Central district of Hong Kong Island up to the heights of the Mid-Levels residential neighborhoods, the escalator is a godsend for footsore travelers.

Escalating the Situation

The Central–Mid-Levels escalator system, which opened in 1993, consists of 18 escalators and three moving sidewalks, and measures 800 meters (1/2 mile) in length, making it the longest outdoor covered escalator in the world. It takes about 20 minutes to ride the escalators from the bottom to the top (or vice versa), but it takes less than that if you walk while they move, as most people do.

The escalators run from 6 A.M. to midnight, descending for the first 4 hours (bringing morning commuters down from upper levels), and then reversing direction around 10:00 A.M. to carry passengers up the hill. There are entrances and exits at each street it intersects, making it easy to stop at whichever level you choose.

Up, Up and Hooray

During the time we spent in Hong Kong, we rode the escalators almost every day, finding them an extremely useful way to get from our hotel midway up the slope of Victoria Peak to the center of activity downtown and back again. One of the things I enjoyed most about riding the escalators was the opportunity to peek at the activity taking place on either side, from apartment life on the upper levels to the bustling bars, restaurants, and stores on the levels closer to the center of the city.

While for many people who rode the escalators alongside us, it was just an ordinary commute to work, we found the journey to be a fascinating glimpse of urban life in Hong Kong. Not only that, but the ease, efficiency, and simplicity of the system made us, foreigners though we were, feel right at home.

Note: This is an updated version of an article that originally appeared on Interesting Thing of the Day on February 26, 2007.