“You understand this…you should write an article.”
My wife told me again. She says this every time a program on TV talks about ADHD.
But I only know about myself. The people on the tube seem to exhibit more severe symptoms than I remember having, but then, I don’t remember it from an observer’s point of view.
It is a problem, but is it a disease or a disorder?
Conventional thinking is that it is a disease because you must have a disease to get the drugs to treat it. The market for these drugs is in the billions of dollars and growing. Over-diagnosis and over-prescribing have spawned a cottage industry in high-profile dissenters who exclaim loudly that it is all a drug industry scam.
Typically, controversy swirls around those who claim its not a disease, but is instead a behavior problem or an allergic response or some nutritional deficiency. A program on television last week featured a doctor who claims that it is all diet and behavior. She believes using drugs is the wrong way to go, an excuse for lazy parents and teachers.
I’m afraid I have to disagree with either side, but I see very little discussion related to my own experience.
I grew up in the fifties and sixties. I was simply lazy and unmotivated, and I did not have an excuse. It did not occur to me that I needed one. I was smart enough to get by with a mix of grades depending on the teacher.
If the teacher spoke passionately in class about the subject and described it with scenarios to illustrate how it happened or worked, I was fine. Still, if I was expected to remember only words or names with some abstract relationship, I was screwed.
I do not remember the sound. I can listen to a song on the radio ten thousand times without being able to recall more than the first three seconds, maybe six words. Growing up, I converted what I heard into visual associations or scenarios and could get by in most situations. It was how my mind worked, and I had no idea there was another way. My mother would say that words went in one ear and out the other. She was right. I used the incoming sound stream to create an image, which was lost. I could not recall it a minute later.
I have come to understand the difference between linear and spatial thinking. I am a spatial thinker. I did poorly with linear thinking in school. Subjects that were rule-based were not the problem so much as the fact that many teachers would teach those subjects by asking you to remember the rules and apply them appropriately. The same subjects taught by a teacher using situational examples were understandable, and I got good grades. Because I am a spatial thinker, I convert sound into spatial imagery and remember the images. I don’t remember sounds, but I recognize them. I know them, but I can’t recall them.
A good way to understand the difference between linear and spatial is to imagine hiking overland, getting from point A to point B. The linear thinker follows the trail, remembering each part of it and the sequence in which the part occurs. The spatial thinker wants to know the context of the entire hike, the large landmarks, and how to get from the beginning to the end. The actual trail is secondary. The spatial thinker expects to make his way through the terrain by deciding the easiest way as he comes to it, not by remembering a line on the ground.
In the April 2002 Popular Science magazine, an article titled “Your Caveman Gramps had Ants in his Pants”, suggests that a genetic mutation that causes hyperactivity was spread through natural selection over the past 50,000 years. It speculates that the variation of gene DRD4, which causes hyperactivity benefited people migrating from Africa. They do this by analyzing the distribution of the gene and calculating its spread from generation to generation. They concluded that it must have given those who possessed it an advantage, making them more likely to procreate.
It would also make them more likely to migrate, giving rise to problems with fitting in with established societies with strong oral traditions and expectations to conform with the words of the leadership. America probably has the largest percentage of ADHD genetics for this reason.
In hunter-gatherer societies, there would be an obvious advantage to those with enhanced spatial thinking abilities. It is unlikely that the successful procreators were dysfunctional misfits. It is much more likely that those who rose to leadership, had children, and protected them until they could survive on their own, were gifted with enhanced abilities to hunt, forage and travel through new territory.
We can assume that most ADHD people today would have been very successful in hunter-gatherer societies, but we do not need to go that far into the past to discover a time when ADHD was not a problem. Before the wide availability of books in the late nineteenth century, most people learned a trade through apprenticeship; they learned by doing. ADHD is not a disadvantage when learning on the job because it works well with their visual/spatial abilities.
The trait of spatial thinkers to look for landmarks and find their own shortest route between two points makes them more creative than the general population. America is the land of the invention for many reasons, but the high percentage of ADHD people must be contributors.
Unfortunately for ADHD people, we now require a substantial amount of linear thinking to succeed. The ability to sit in a chair and attend to what is being said is now the foundation of education. The “hyperactive” are branded as troublemakers. Their difficulty with learning in this fashion is generalized as an overall stupidity or that they are lazy and unwilling to try. They are thought of as behavior problems.
ADHD is not a behavior problem, but it can lead to one. Continually tell someone that they are not trying when they are and see if they do not become angry and confused and act out. If they are behavior problems, it is because of the unrealistic expectations that are put on them. Simply having ADHD is not a cause for willful disruptive behavior. Outbursts of anger and scolding from parents and teachers lead to imitative behavior by the ADHDer toward peers and those younger.
ADHD people need to move to think. Movement through space drives the exchange between the brain halves that we now know to be the requirement for “thought.” ADHDers lack an adequate supply of the neurotransmitter dopamine, which is used for processing language.
Talking to yourself
It may seem strange to those without ADHD, but the ability to dialog quietly in your head is associated with adequate supplies of the neurotransmitter dopamine. Without it the dialog is exhausted after a few sentences or less. So when an ADHDer sits in class and listens to a lecturer go on about something they can not visualize, the surrounding visual and auditory stimulation begins to drive visual/spatial associations unrelated to what he or she started to do only moments before.
And they cannot help it. It is not a behavior problem; it is a natural behavior.
Teaching those with ADHD must begin by recognizing what they can and can not do. It is not about intelligence. It is about ability. The ability to think is driven by the movement and visual/spatial cues. Classes that enable the ADHDer to learn while moving will allow him or her to build the internal associations required to store information for later recall. All subjects can be taught to the ADHD student when visual/spatial associations are combined with contextual meaning. Topics normally considered “linear,” such as language or math, can be taught through scenarios or situational examples using the ADHDer’s path-finding and problem-solving skills by emphasizing the journey’s goals in the context of its environment.
Classes should begin by making a presentation that explains with real-life scenarios why the subject and class are important and present to the students a puzzle of getting from where they are at that moment and how they will get where they need to be at the end of the class. It must be a puzzle to be solved through daily accomplishments, understandable in context, and visualizable from the beginning.
This is what I believe would have enabled me to learn easily in school and reflects all the insight I have accumulated as an individual with ADHD. It is not a prescription for a new kind of educational institution. It is intended to provide some insight to those currently dealing with an ADHD child and has only been exposed to the behaviorist approach to ADHD.
Could you do your research and think about it? Not all of those diagnosed with ADHD have it as an inherited condition. However, many parents grew up with it and seek treatment with an acute understanding of its difficulties and want a better life for their child than they experienced. I would like them to realize that this is only a problem because of the expectations of the institutional school system and not a disease or disorder.
An informed and aware choice of drug therapy can be a real benefit to a child, but the opportunity for harm is too great to treat it casually. Fitting in and progressing with peers is critical, so when the situation insists that your ADHD child attend an institutionally run school, it can be a wise and beneficial choice. It should be regarded as an opportunity to experience life in an average way but in the context of the child’s other unique abilities.
About drug therapy
Drug therapy is not needed for an ADHD student to succeed at learning or in life, but it may enable him or her to express what they have learned in writing.
Writing requires the ability to hold a thought as language and edit it for content in the context of what has already been saying and what will be said in the entire piece. This is very hard to do when you have ADHD.
I have ADHD and learned to write after using appropriate medication to supplement my naturally low dopamine levels. I started taking meds after I was forty-three years old, and it took me years to express a complex thought in writing. It was very different than speaking because the sound of my voice would supply the auditory stimulation to drive my thought processes. In school, I could explain the answer to a question in class but could not write the same information as the answer to an essay question. As soon as I began to write, my mind would go blank. It was as if the pen in hand was a switch that turned my mind to mush.
I never felt it would be impossible to get my ideas into print, though, because I loved to share them in conversation, and there were always others who could be recruited to do the writing. I later discovered that complex ideas are too difficult to convey secondhand and that I had to do it myself or it would not happen. I’m still working on them, but this small commentary is a good exercise.
Dane M. Arr
Tempe AZ
9/9/02
But the dark matter hypothesis assumes scientists know how matter in the sky ought to move in the first place. This month, a series of developments has revived a long-disfavored argument that dark matter doesn’t exist after all. In this view, no missing matter is needed to explain the errant motions of the heavenly bodies; rather, on cosmic scales, gravity itself works in a different way than either Isaac Newton or Albert Einstein predicted.
Instead of hordes of invisible particles, “dark matter is an interplay between ordinary matter and dark energy,” Verlinde said.
To make his case, Verlinde has adopted a radical perspective on the origin of gravity that is currently in vogue among leading theoretical physicists. Einstein defined gravity as the effect of curves in space-time created by the presence of matter. According to the new approach, gravity is an emergent phenomenon. Space-time and the matter within it are treated as a hologram that arises from an underlying network of quantum bits (called “qubits”), much as the three-dimensional environment of a computer game is encoded in classical bits on a silicon chip. Working within this framework, Verlinde traces dark energy to a property of these underlying qubits that supposedly encode the universe. On large scales in the hologram, he argues, dark energy interacts with matter in just the right way to create the illusion of dark matter.
In his calculations, Verlinde rediscovered the equations of “modified Newtonian dynamics,” or MOND. This 30-year-old theory makes an ad hoc tweak to the famous “inverse-square” law of gravity in Newton’s and Einstein’s theories in order to explain some of the phenomena attributed to dark matter. That this ugly fix works at all has long puzzled physicists. “I have a way of understanding the MOND success from a more fundamental perspective,” Verlinde said.
Many experts have called Verlinde’s paper compelling but hard to follow. While it remains to be seen whether his arguments will hold up to scrutiny, the timing is fortuitous. In a new analysis of galaxiespublished on Nov. 9 in Physical Review Letters, three astrophysicists led by Stacy McGaugh of Case Western Reserve University in Cleveland, Ohio, have strengthened MOND’s case against dark matter.
The researchers analyzed a diverse set of 153 galaxies, and for each one they compared the rotation speed of visible matter at any given distance from the galaxy’s center with the amount of visible matter contained within that galactic radius. Remarkably, these two variables were tightly linked in all the galaxies by a universal law, dubbed the “radial acceleration relation.” This makes perfect sense in the MOND paradigm, since visible matter is the exclusive source of the gravity driving the galaxy’s rotation (even if that gravity does not take the form prescribed by Newton or Einstein). With such a tight relationship between gravity felt by visible matter and gravity given by visible matter, there would seem to be no room, or need, for dark matter.
Even as dark matter proponents rise to its defense, a third challenge has materialized. In new research that has been presented at seminars and is under review by the Monthly Notices of the Royal Astronomical Society, a team of Dutch astronomers have conducted what they call the first test of Verlinde’s theory: In comparing his formulas to data from more than 30,000 galaxies, Margot Brouwer of Leiden University in the Netherlands and her colleagues found that Verlinde correctly predicts the gravitational distortion or “lensing” of light from the galaxies — another phenomenon that is normally attributed to dark matter. This is somewhat to be expected, as MOND’s original developer, the Israeli astrophysicist Mordehai Milgrom, showed years ago that MOND accounts for gravitational lensing data. Verlinde’s theory will need to succeed at reproducing dark matter phenomena in cases where the old MOND failed.
Kathryn Zurek, a dark matter theorist at Lawrence Berkeley National Laboratory, said Verlinde’s proposal at least demonstrates how something like MOND might be right after all. “One of the challenges with modified gravity is that there was no sensible theory that gives rise to this behavior,” she said. “If [Verlinde’s] paper ends up giving that framework, then that by itself could be enough to breathe more life into looking at [MOND] more seriously.”
The New MOND
In Newton’s and Einstein’s theories, the gravitational attraction of a massive object drops in proportion to the square of the distance away from it. This means stars orbiting around a galaxy should feel less gravitational pull — and orbit more slowly — the farther they are from the galactic center. Stars’ velocities do drop as predicted by the inverse-square law in the inner galaxy, but instead of continuing to drop as they get farther away, their velocities level off beyond a certain point. The “flattening” of galaxy rotation speeds, discovered by the astronomer Vera Rubin in the 1970s, is widely considered to be Exhibit A in the case for dark matter — explained, in that paradigm, by dark matter clouds or “halos” that surround galaxies and give an extra gravitational acceleration to their outlying stars.
Lucy Reading-Ikkanda for Quanta Magazine
Searches for dark matter particles have proliferated — with hypothetical “weakly interacting massive particles” (WIMPs) and lighter-weight “axions” serving as prime candidates — but so far, experiments have found nothing.
Meanwhile, in the 1970s and 1980s, some researchers, including Milgrom, took a different tack. Many early attempts at tweaking gravity were easy to rule out, but Milgrom found a winning formula: When the gravitational acceleration felt by a star drops below a certain level — precisely 0.00000000012 meters per second per second, or 100 billion times weaker than we feel on the surface of the Earth — he postulated that gravity somehow switches from an inverse-square law to something close to an inverse-distance law. “There’s this magic scale,” McGaugh said. “Above this scale, everything is normal and Newtonian. Below this scale is where things get strange. But the theory does not really specify how you get from one regime to the other.”
Physicists do not like magic; when other cosmological observations seemed far easier to explain with dark matter than with MOND, they left the approach for dead. Verlinde’s theory revitalizes MOND by attempting to reveal the method behind the magic.
Verlinde, ruddy and fluffy-haired at 54 and lauded for highly technical string theory calculations, first jotted down a back-of-the-envelope version of his idea in 2010. It built on a famous paper he had written months earlier, in which he boldly declared that gravity does not really exist. By weaving together numerous concepts and conjectures at the vanguard of physics, he had concluded that gravity is an emergent thermodynamic effect, related to increasing entropy (or disorder). Then, as now, experts were uncertain what to make of the paper, though it inspired fruitful discussions.
The particular brand of emergent gravity in Verlinde’s paper turned out not to be quite right, but he was tapping into the same intuition that led other theorists to develop the modern holographic description of emergent gravity and space-time — an approach that Verlinde has now absorbed into his new work.
In this framework, bendy, curvy space-time and everything in it is a geometric representation of pure quantum information — that is, data stored in qubits. Unlike classical bits, qubits can exist simultaneously in two states (0 and 1) with varying degrees of probability, and they become “entangled” with each other, such that the state of one qubit determines the state of the other, and vice versa, no matter how far apart they are. Physicists have begun to work out the rules by which the entanglement structure of qubits mathematically translates into an associated space-time geometry. An array of qubits entangled with their nearest neighbors might encode flat space, for instance, while more complicated patterns of entanglement give rise to matter particles such as quarks and electrons, whose mass causes the space-time to be curved, producing gravity. “The best way we understand quantum gravity currently is this holographic approach,” said Mark Van Raamsdonk, a physicist at the University of British Columbia in Vancouver who has done influential work on the subject.
The mathematical translations are rapidly being worked out for holographic universes with an Escher-esque space-time geometry known as anti-de Sitter (AdS) space, but universes like ours, which have de Sitter geometries, have proved far more difficult. In his new paper, Verlinde speculates that it’s exactly the de Sitter property of our native space-time that leads to the dark matter illusion.
De Sitter space-times like ours stretch as you look far into the distance. For this to happen, space-time must be infused with a tiny amount of background energy — often called dark energy — which drives space-time apart from itself. Verlinde models dark energy as a thermal energy, as if our universe has been heated to an excited state. (AdS space, by contrast, is like a system in its ground state.) Verlinde associates this thermal energy with long-range entanglement between the underlying qubits, as if they have been shaken up, driving entangled pairs far apart. He argues that this long-range entanglement is disrupted by the presence of matter, which essentially removes dark energy from the region of space-time that it occupied. The dark energy then tries to move back into this space, exerting a kind of elastic response on the matter that is equivalent to a gravitational attraction.
Because of the long-range nature of the entanglement, the elastic response becomes increasingly important in larger volumes of space-time. Verlinde calculates that it will cause galaxy rotation curves to start deviating from Newton’s inverse-square law at exactly the magic acceleration scale pinpointed by Milgrom in his original MOND theory.
Van Raamsdonk calls Verlinde’s idea “definitely an important direction.” But he says it’s too soon to tell whether everything in the paper — which draws from quantum information theory, thermodynamics, condensed matter physics, holography and astrophysics — hangs together. Either way, Van Raamsdonk said, “I do find the premise interesting, and feel like the effort to understand whether something like that could be right could be enlightening.”
One problem, said Brian Swingle of Harvard and Brandeis universities, who also works in holography, is that Verlinde lacks a concrete model universe like the ones researchers can construct in AdS space, giving him more wiggle room for making unproven speculations. “To be fair, we’ve gotten further by working in a more limited context, one which is less relevant for our own gravitational universe,” Swingle said, referring to work in AdS space. “We do need to address universes more like our own, so I hold out some hope that his new paper will provide some additional clues or ideas going forward.”
The Case for Dark Matter
Verlinde could be capturing the zeitgeist the way his 2010 entropic-gravity paper did. Or he could be flat-out wrong. The question is whether his new and improved MOND can reproduce phenomena that foiled the old MOND and bolstered belief in dark matter.
One such phenomenon is the Bullet cluster, a galaxy cluster in the process of colliding with another. The visible matter in the two clusters crashes together, but gravitational lensing suggests that a large amount of dark matter, which does not interact with visible matter, has passed right through the crash site. Some physicists consider this indisputable proof of dark matter. However, Verlinde thinks his theory will be able to handle the Bullet cluster observations just fine. He says dark energy’s gravitational effect is embedded in space-time and is less deformable than matter itself, which would have allowed the two to separate during the cluster collision.
But the crowning achievement for Verlinde’s theory would be to account for the suspected imprints of dark matter in the cosmic microwave background (CMB), ancient light that offers a snapshot of the infant universe. The snapshot reveals the way matter at the time repeatedly contracted due to its gravitational attraction and then expanded due to self-collisions, producing a series of peaks and troughs in the CMB data. Because dark matter does not interact, it would only have contracted without ever expanding, and this would modulate the amplitudes of the CMB peaks in exactly the way that scientists observe. One of the biggest strikes against the old MOND was its failure to predict this modulation and match the peaks’ amplitudes. Verlinde expects that his version will work — once again, because matter and the gravitational effect of dark energy can separate from each other and exhibit different behaviors. “Having said this,” he said, “I have not calculated this all through.”
While Verlinde confronts these and a handful of other challenges, proponents of the dark matter hypothesis have some explaining of their own to do when it comes to McGaugh and his colleagues’ recent findings about the universal relationship between galaxy rotation speeds and their visible matter content.
In October, responding to a preprint of the paper by McGaugh and his colleagues, two teams of astrophysicists independently argued that the dark matter hypothesis can account for the observations. They say the amount of dark matter in a galaxy’s halo would have precisely determined the amount of visible matter the galaxy ended up with when it formed. In that case, galaxies’ rotation speeds, even though they’re set by dark matter and visible matter combined, will exactly correlate with either their dark matter content or their visible matter content (since the two are not independent). However, computer simulations of galaxy formation do not currently indicate that galaxies’ dark and visible matter contents will always track each other. Experts are busy tweaking the simulations, but Arthur Kosowsky of the University of Pittsburgh, one of the researchers, working on them, says it’s too early to tell if the simulations will be able to match all 153 examples of the universal law in McGaugh and his colleagues’ galaxy data set. If not, then the standard dark matter paradigm is in big trouble. “Obviously this is something that the community needs to look at more carefully,” Zurek said.
Even if the simulations can be made to match the data, McGaugh, for one, considers it an implausible coincidence that dark matter and the visible matter would conspire to exactly mimic the predictions of MOND at every location in every galaxy. “If somebody were to come to you and say, ‘The solar system doesn’t work on an inverse-square law, really it’s an inverse-cube law, but there’s dark matter that’s arranged just so that it always looks inverse-square,’ you would say that person is insane,” he said. “But that’s basically what we’re asking to be the case with dark matter here.”
Given the considerable indirect evidence and near consensus among physicists that dark matter exists, it still probably does, Zurek said. “That said, you should always check that you’re not on a bandwagon,” she added. “Even though this paradigm explains everything, you should always check that there isn’t something else going on.”
This article was reprinted on TheAtlantic.com.