Another technological advance we might see by midcentury is true 3-D TV and movies. Back in the 1950s, 3-D movies required that you put on clunky gla.s.ses whose lenses were colored blue and red. This took advantage of the fact that the left eye and the right eye are slightly misaligned; the movie screen displayed two images, one blue and one red. Since these gla.s.ses acted as filters that gave two distinct images to the left and right eye, this gave the illusion of seeing three dimensions when the brain merged the two images. Depth perception, therefore, was a trick. (The farther apart your eyes are, the greater the depth perception. That is why some animals have eyes outside their heads: to give them maximum depth perception.) One improvement is to have 3-D gla.s.ses made of polarized gla.s.s, so that the left eye and right eye are shown two different polarized images. In this way, one can see 3-D images in full color, not just in blue and red. Since light is a wave, it can vibrate up and down, or left and right. A polarized lens is a piece of gla.s.s that allows only one direction of light to pa.s.s through. Therefore, if you have two polarized lenses in your gla.s.ses, with different directions of polarization, you can create a 3-D effect. A more sophisticated version of 3-D may be to have two different images flashed into our contact lens.
3-D TVs that require wearing special gla.s.ses have already hit the market. But soon, 3-D TVs will no longer require them, instead using lenticular lenses. The TV screen is specially made so that it projects two separate images at slightly different angles, one for each eye. Hence your eyes see separate images, giving the illusion of 3-D. However, your head must be positioned correctly; there are "sweet spots" where your eyes must lie as you gaze at the screen. (This takes advantage of a well-known optical illusion. In novelty stores, we see pictures that magically transform as we walk past them. This is done by taking two pictures, shredding each one into many thin strips, and then interspersing the strips, creating a composite image. Then a lenticular gla.s.s sheet with many vertical grooves is placed on top of the composite, each groove sitting precisely on top of two strips. The groove is specially shaped so that, as you gaze upon it from one angle, you can see one strip, but the other strip appears from another angle. Hence, by walking past the gla.s.s sheet, we see each picture suddenly transform from one into the other, and back again. 3-D TVs will replace these still pictures with moving images to attain the same effect without the use of gla.s.ses.) But the most advanced version of 3-D will be holograms. Without using any gla.s.ses, you would see the precise wave front of a 3-D image, as if it were sitting directly in front of you. Holograms have been around for decades (they appear in novelty shops, on credit cards, and at exhibitions), and they regularly are featured in science fiction movies. In Star Wars, Star Wars, the plot was set in motion by a 3-D holographic distress message sent from Princess Leia to members of the Rebel Alliance. the plot was set in motion by a 3-D holographic distress message sent from Princess Leia to members of the Rebel Alliance.
The problem is that holograms are very hard to create.
Holograms are made by taking a single laser beam and splitting it in two. One beam falls on the object you want to photograph, which then bounces off and falls onto a special screen. The second laser beam falls directly onto the screen. The mixing of the two beams creates a complex interference pattern containing the "frozen" 3-D image of the original object, which is then captured on a special film on the screen. Then, by flashing another laser beam through the screen, the image of the original object comes to life in full 3-D.
There are two problems with holographic TV. First, the image has to be flashed onto a screen. Sitting in front of the screen, you see the exact 3-D image of the original object. But you cannot reach out and touch the object. The 3-D image you see in front of you is an illusion.
This means that if you are watching a 3-D football game on your holographic TV, no matter how you move, the image in front of you changes as if it were real. It might appear that you are sitting right at the 50-yard line, watching the game just inches from the football players. However, if you were to reach out to grab the ball, you would b.u.mp into the screen.
The real technical problem that has prevented the development of holographic TV is that of information storage. A true 3-D image contains a vast amount of information, many times the information stored inside a single 2-D image. Computers regularly process 2-D images, since the image is broken down into tiny dots, called pixels, and each pixel is illuminated by a tiny transistor. But to make a 3-D image move, you need to flash thirty images per second. A quick calculation shows that the information needed to generate moving 3-D holographic images far exceeds the capability of today"s Internet.
By midcentury, this problem may be resolved as the bandwidth of the Internet expands exponentially.
What might true 3-D TV look like?
One possibility is a screen shaped like a cylinder or dome that you sit inside. When the holographic image is flashed onto the screen, we see the 3-D images surrounding us, as if they were really there.
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MIND OVER MATTER.
By the end of this century, we will control computers directly with our minds. Like Greek G.o.ds, we will think of certain commands and our wishes will be obeyed. The foundation for this technology has already been laid. But it may take decades of hard work to perfect it. This revolution is in two parts: First, the mind must be able to control objects around it. Second, a computer has to decipher a person"s wishes in order to carry them out.
The first significant breakthrough was made in 1998, when scientists at Emory University and the University of Tubingen, Germany, put a tiny gla.s.s electrode directly into the brain of a fifty-six-year-old man who was paralyzed after a stroke. The electrode was connected to a computer that a.n.a.lyzed the signals from his brain. The stroke victim was able to see an image of the cursor on the computer screen. Then, by biofeedback, he was able to control the cursor of the computer display by thinking alone. For the first time, a direct contact was made between the human brain and a computer.
The most sophisticated version of this technology has been developed at Brown University by neuroscientist John Donoghue, who has created a device called BrainGate to help people who have suffered debilitating brain injuries communicate. He created a media sensation and even made the cover of Nature Nature magazine in 2006. magazine in 2006.
Donoghue told me that his dream is to have BrainGate revolutionize the way we treat brain injuries by harnessing the full power of the information revolution. It has already had a tremendous impact on the lives of his patients, and he has high hopes of furthering this technology. He has a personal interest in this research because, as a child, he was confined to a wheelchair due to a degenerative disease and hence knows the feeling of helplessness.
His patients include stroke victims who are completely paralyzed and unable to communicate with their loved ones, but whose brains are active. He has placed a chip, just 4 millimeters wide, on top of a stroke victim"s brain, in the area that controls motor movements. This chip is then connected to a computer that a.n.a.lyzes and processes the brain signals and eventually sends the message to a laptop.
At first the patient has no control over the location of the cursor, but can see where the cursor is moving. By trial and error, the patient learns to control the cursor, and, after several hours, can position the cursor anywhere on the screen. With practice, the stroke victim is able to read and write e-mails and play video games. In principle a paralyzed person should be able to perform any function that can be controlled by the computer.
Initially, Donoghue started with four patients, two who had spinal cord injuries, one who"d had a stroke, and a fourth who had ALS (amyotrophic lateral sclerosis). One of them, a quadriplegic paralyzed from the neck down, took only a day to master the movement of the cursor with his mind. Today, he can control a TV, move a computer cursor, play a video game, and read e-mail. Patients can also control their mobility by manipulating a motorized wheelchair.
In the short term, this is nothing less than miraculous for people who are totally paralyzed. One day, they are trapped, helpless, in their bodies; the next day, they are surfing the Web and carrying on conversations with people around the world.
(I once attended a gala reception at Lincoln Center in New York in honor of the great cosmologist Stephen Hawking. It was heartbreaking to see him strapped into a wheelchair, unable to move anything but a few facial muscles and his eyelids, with nurses holding up his limp head and pushing him around. It takes him hours and days of excruciating effort to communicate simple ideas via his voice synthesizer. I wondered if it was not too late for him to take advantage of the technology of BrainGate. Then John Donoghue, who was also in the audience, came up to greet me. So perhaps BrainGate is Hawking"s best option.) Another group of scientists at Duke University have achieved similar results in monkeys. Miguel A. L. Nicolelis and his group have placed a chip on the brain of a monkey. The chip is connected to a mechanical arm. At first, the monkey flails about, not understanding how to operate the mechanical arm. But with some practice, these monkeys, using the power of their brains, are able to slowly control the motions of the mechanical arm-for example, moving it so that it grabs a banana. They can instinctively move these arms without thinking, as if the mechanical arm is their own. "There"s some physiological evidence that during the experiment they feel more connected to the robots than to their own bodies," says Nicolelis.
This also means that we will one day be able to control machines using pure thought. People who are paralyzed may be able to control mechanical arms and legs in this way. For example, one might be able to connect a person"s brain directly to mechanical arms and legs, bypa.s.sing the spinal cord, so the patient can walk again. Also, this may lay the foundation for controlling our world via the power of the mind.
MIND READING.
If the brain can control a computer or mechanical arm, can a computer read the thoughts of a person, without placing electrodes inside the brain?
It"s been known since 1875 that the brain is based on electricity moving through its neurons, which generates faint electrical signals that can be measured by placing electrodes around a person"s head. By a.n.a.lyzing the electrical impulses picked up by these electrodes, one can record the brain waves. This is called an EEG (electroencephalogram), which can record gross changes in the brain, such as when it is sleeping, and also moods, such as agitation, anger, etc. The output of the EEG can be displayed on a computer screen, which the subject can watch. After a while, the person is able to move the cursor by thinking alone. Already, Niels Birbaumer of the University of Tubingen has been able to train partially paralyzed people to type simple sentences via this method.
Even toy makers are taking advantage of this. A number of toy companies, including NeuroSky, market a headband with an EEG-type electrode inside. If you concentrate in a certain way, you can activate the EEG in the headband, which then controls the toy. For example, you can raise a Ping-Pong ball inside a cylinder by sheer thought.
The advantage of the EEG is that it can rapidly detect various frequencies emitted by the brain without elaborate, expensive equipment. But one large disadvantage is that the EEG cannot localize thoughts to specific locations of the brain.
A much more sensitive method is the fMRI (functional magnetic resonance imaging) scan. EEG and fMRI scans differ in important ways. The EEG scan is a pa.s.sive device that simply picks up electrical signals from the brain, so we cannot determine very well the location of the source. An fMRI machine uses "echoes" created by radio waves to peer inside living tissue. This allows us to pinpoint the location of the various signals, giving us spectacular 3-D images of inside the brain.
The fMRI machine is quite expensive and requires a laboratory full of heavy equipment, but already it has given us breathtaking details of how the thinking brain functions. The fMRI scan allows scientists to locate the presence of oxygen contained within hemoglobin in the blood. Since oxygenated hemoglobin contains the energy that fuels cell activity, detecting the flow of this oxygen allows one to trace the flow of thoughts in the brain.
Joshua Freedman, a psychiatrist at the University of California, Los Angeles, says: "It"s like being an astronomer in the sixteenth century after the invention of the telescope. For millennia, very smart people tried to make sense of what was going on up in the heavens, but they could only speculate about what lay beyond unaided human vision. Then, suddenly, a new technology let them see directly what was there."
In fact, fMRI scans can even detect the motion of thoughts in the living brain to a resolution of .1 millimeter, or smaller than the head of a pin, which corresponds to perhaps a few thousand neurons. An fMRI can thus give three-dimensional pictures of the energy flow inside the thinking brain to astonishing accuracy. Eventually, fMRI machines may be built that can probe to the level of single neurons, in which case one might be able to pick out the neural patterns corresponding to specific thoughts.
A breakthrough was made recently by Kendrick Kay and his colleagues at the University of California at Berkeley. They did an fMRI scan of people as they looked at pictures of a variety of objects, such as food, animals, people, and common things of various colors. Kay and colleagues created a software program that could a.s.sociate these objects with the corresponding fMRI patterns. The more objects these subjects saw, the better the computer program was at identifying these objects on their fMRI scans.
Then they showed the same subjects entirely new objects, and the software program was often able to correctly match the object with the fMRI scan. When shown 120 pictures of new objects, the software program correctly identified the fMRI scan with these objects 90 percent of the time. When the subjects were shown 1,000 new pictures, the software program"s success rate was 80 percent.
Kay says it is "possible to identify, from a large set of completely novel natural images, which specific image was seen by an observer.... It may soon be possible to reconstruct a picture of a person"s visual experience from measurements of brain activity alone."
The goal of this approach is to create a "dictionary of thought," so that each object has a one-to-one correspondence to a certain fMRI image. By reading the fMRI pattern, one can then decipher what object the person is thinking about. Eventually, a computer will scan perhaps thousands of fMRI patterns that come pouring out of a thinking brain and decipher each one. In this way, one may be able to decode a person"s stream of consciousness.
PHOTOGRAPHING A DREAM.
The problem with this technique, however, is that while it might be able to tell if you are thinking of a dog, for example, it cannot reproduce the actual image of the dog itself. One new line of research is to try to reconstruct the precise image that the brain is thinking of, so that one might be able to create a video of a person"s thoughts. In this way, one might be able to make a video recording of a dream.
Since time immemorial, people have been fascinated by dreams, those ephemeral images that are sometimes so frustrating to recall or understand. Hollywood has long envisioned machines that might one day send dreamlike thoughts into the brain or even record them, as in movies like Total Recall. Total Recall. All this, however, was sheer speculation. All this, however, was sheer speculation.
Until recently, that is.
Scientists have made remarkable progress in an area once thought to be impossible: taking a snapshot of our memories and possibly our dreams. The first steps in this direction were taken by scientists at the Advanced Telecommunications Research (ATR) Computational Neuroscience Laboratory in Kyoto. They showed their subjects a pinpoint of light at a particular location. Then they used an fMRI scan to record where the brain stored this information. They moved the pinpoint of light and recorded where the brain stored this new image. Eventually, they had a one-to-one map of where scores of pinpoints of light were stored in the brain. These pinpoints were located on a 10 10 grid.
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(photo credit 1.3)
Then the scientists flashed a picture of a simple object made from these 10 10 points, such as a horseshoe. By computer they could then a.n.a.lyze how the brain stored this picture. Sure enough, the pattern stored by the brain was the sum of the images that made up the horseshoe.
In this way, these scientists could create a picture of what the brain is seeing. Any pattern of lights on this 10 10 grid can be decoded by a computer looking at the fMRI brain scans.
In the future, these scientists want to increase the number of pixels in their 10 10 grid. Moreover, they claim that this process is universal, that is, any visual thought or even dream should be able to be detected by the fMRI scan. If true, it might mean that we will be able to record, for the first time in history, the images we are dreaming about.
Of course, our mental images, and especially our dreams, are never crystal sharp, and there will always be a certain fuzziness, but the very fact that we can look deeply into the visual thoughts of someone"s brain is remarkable.
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Reading thoughts via EEG (left) and fMRI (right) scans. In the future, these electrodes will be miniaturized. We will be able to read thoughts and also command objects by simply thinking. (photo credit 1.4)
ETHICS OF MIND READING.
This poses a problem: What happens if we can routinely read people"s thoughts? n.o.bel laureate David Baltimore, former president of the California Inst.i.tute of Technology (Caltech), worries about this problem. He writes, "Can we tap into the thoughts of others?...I don"t think that"s pure science fiction, but it would create a h.e.l.l of a world. Imagine courting a mate if your thoughts could be read, or negotiating a contract if your thoughts could be read."
Most of the time, he speculates, mind reading will have some embarra.s.sing but not disastrous consequences. He writes, "I am told that if you stop a professor"s lecture in midstream...a significant fraction [of the students] are involved in erotic fantasies."
But perhaps mind reading won"t become such a privacy issue, since most of our thoughts are not well defined. Photographing our daydreams and dreams may one day be possible, but we may be disappointed with the quality of the pictures. Years ago, I remember reading a short story in which a man was told by a genie that he could have anything he could imagine. He immediately imagined expensive luxury items, like limousines, millions of dollars in cash, and a castle. Then the genie instantly materialized them. But when the man examined them carefully, he was shocked that the limousine had no door handles or engine, the faces on the bills were blurry, and the castle was empty. In his rush to imagine all these items, he forgot that these images exist in his imagination only as general ideas.
Furthermore, it is doubtful that you can read someone"s mind from a distance. All the methods studied so far (including EEG, fMRI, and electrodes on the brain itself) require close contact with the subject.
Nonetheless, laws may eventually be pa.s.sed to limit unauthorized mind reading. Also, devices may be created to protect our thoughts by jamming, blocking, or scrambling our electrical signals.
True mind reading is still many decades away. But at the very least, an fMRI scanner might function as a primitive lie detector. Telling a lie causes more centers of the brain to light up than telling the truth. Telling a lie implies that you know the truth but are thinking of the lie and its myriad consequences, which requires much more energy than telling the truth. Hence, the fMRI brain scan should be able to detect this extra expenditure of energy. At present, the scientific community has some reservations about allowing fMRI lie detectors to be the last word, especially in court cases. The technology is still too new to provide a foolproof lie-detection method. Further research, say its promoters, will refine its accuracy. This technology is here to stay.
Already, there are two commercial companies offering fMRI lie detectors, claiming a more than 90 percent success rate. A court in India already has used an fMRI to settle a case, and several cases involving fMRI are now in U.S. courts.
Ordinary lie detectors do not measure lies; they measure only signs of tension, such as increased sweating (measured by a.n.a.lyzing the conductivity of the skin) and increased heart rate. Brain scans measure increased brain activity, but the correlation between this and lying has still to be proven conclusively for a court of law.
It may take years of careful testing to explore the limits and accuracy of fMRI lie detection. In the meantime, the MacArthur Foundation recently gave a $10 million grant to the Law and Neuroscience Project to determine how neuroscience will affect the law.
MY fMRI BRAIN SCAN
I once had my own brain scanned by an fMRI machine. For a BBC/Discovery Channel doc.u.mentary, I flew to Duke University, where they placed me on a stretcher, which was then inserted into a gigantic metal cylinder. When a huge, powerful magnet was turned on (20,000 times the earth"s magnetic field), the atoms in my brain were aligned to the magnetic field, like spinning tops whose axes point in one direction. Then a radio pulse was sent into my brain, which flipped some of the nuclei of my atoms upside down. When the nuclei eventually flipped back to normal, they emitted a tiny pulse, or "echo," that could be detected by the fMRI machine. By a.n.a.lyzing these echoes, computers could process the signals, then rea.s.semble a 3-D map of the interior of my brain.
The whole process was totally painless and harmless. The radiation sent into my body was non-ionizing and could not cause damage to my cells by ripping apart atoms. Even suspended in a magnetic field thousands of times stronger than the earth"s, I could not detect the slightest change in my body.
The purpose of my being in the fMRI scan was to determine precisely where in my brain certain thoughts were being manufactured. In particular, there is a tiny biological "clock" inside your brain, just between your eyes, behind your nose, where the brain calculates seconds and minutes. Damage to this delicate part of the brain causes a distorted sense of time.
While inside the scanner, I was asked to measure the pa.s.sage of seconds and minutes. Later, when the fMRI pictures were developed, I could clearly see that there was a bright spot just behind my nose as I was counting the seconds. I realized that I was witnessing the birth of an entirely new area of biology: tracking down the precise locations in the brain a.s.sociated with certain thoughts, a form of mind reading.
TRICORDERS AND PORTABLE BRAIN SCANS.
In the future, the MRI machine need not be the monstrous device found in hospitals today, weighing several tons and taking up an entire room. It might be as small as a cell phone, or even a penny.
In 1993, Bernhard Blumich and his colleagues, when they were at the Max Planck Inst.i.tute for Polymer Research in Mainz, Germany, hit upon a novel idea that could create tiny MRI machines. They built a new machine, called the MRI-MOUSE (mobile universal surface explorer), currently about one foot tall, that may one day give us MRI machines that are the size of a coffee cup and sold in department stores. This could revolutionize medicine, since one would be able to perform MRI scans in the privacy of one"s home. Blumich envisions a time, not too far away, when a person would be able to pa.s.s his personal MRI-MOUSE over his skin and look inside his body any time of the day. Computers would a.n.a.lyze the picture and diagnose any problems. "Perhaps something like the Star Trek Star Trek tricorder is not so far off after all," he has concluded. tricorder is not so far off after all," he has concluded.
(MRI scans work on a principle similar to compa.s.s needles. The north pole of the compa.s.s needle immediately aligns to the magnetic field. So when the body is placed in an MRI machine, the nuclei of the atoms, like compa.s.s needles, align to the magnetic field. Now a radio pulse is sent into the body which makes the nuclei flip upside down. Eventually, the nuclei flips back to its original position, emitting a second radio pulse or "echo.") The key to his mini-MRI machine is its nonuniform magnetic fields. Normally, the reason the MRI machine of today is so bulky is because you need to place the body in an extremely uniform magnetic field. The greater the uniformity of the field, the more detailed the resulting picture, which today can resolve features down to a tenth of a millimeter. To obtain these uniform magnetic fields, physicists start with two large coils of wire, roughly two feet in diameter, stacked on top of each other. This is called a Helmholtz coil, and provides a uniform magnetic field in the s.p.a.ce between the two coils. The human body is then placed along the axis of these two large magnets.
But if you use nonuniform magnetic fields, the resulting image is distorted and useless. This has been the problem with MRI machines for many decades. But Blumich stumbled on a clever way to compensate for this distortion by sending multiple radio pulses into the sample and then detecting the resulting echoes. Then computers are used to a.n.a.lyze these echoes and make up for the distortion created by nonuniform magnetic fields.
Today, Blumich"s portable MRI-MOUSE machine uses a small U-shaped magnet that produces a north pole and a south pole at each end of the U. This magnet is placed on top of the patient, and by moving the magnet, one can peer several inches beneath the skin. Unlike standard MRI machines, which consume vast amounts of power and have to have special electrical power outlets, the MRI-MOUSE uses only about as much electricity as an ordinary lightbulb.
In some of his early tests, Blumich placed the MRI-MOUSE on top of rubber tires, which are soft like human tissue. This could have an immediate commercial application: rapidly scanning for defects in products. Conventional MRI machines cannot be used on objects that contain metal, such as steel-belted radial tires. The MRI-MOUSE, because it uses only weak magnetic fields, has no such limitation. (The magnetic fields of a conventional MRI machine are 20,000 times more powerful than the earth"s magnetic field. Many nurses and technicians have been seriously hurt when the magnetic field is turned on and then metal tools suddenly come flying at them. The MRI-MOUSE has no such problem.) Not only is this ideal to a.n.a.lyze objects that have ferrous metals in them, it can also a.n.a.lyze objects that are too large to fit inside a conventional MRI machine or cannot be moved from their sites. For example, in 2006 the MRI-MOUSE successfully produced images of the interior of otzi the iceman, the frozen corpse found in the Alps in 1991. By moving the U-shaped magnet over otzi, it was able to successively peel away the various layers of his frozen body.
In the future, the MRI-MOUSE may be miniaturized even more, allowing for MRI scans of the brain using something the size of a cell phone. Then, scanning the brain to read one"s thoughts may not be such a problem. Eventually, the MRI scanner may be as thin as a dime, barely noticeable. It might even resemble the less-powerful EEG, where you put a plastic cap with many electrodes attached over your head. (If you place these portable MRI disks on your fingertips and then place them on a person"s head, this would resemble performing the Vulcan mind meld of Star Trek. Star Trek.) TELEKINESIS AND THE POWER OF THE G.o.dS.
The endpoint of this progression is to attain telekinesis, the power of the G.o.ds of mythology to move objects by sheer thought.
In the movie Star Wars, Star Wars, for example, the Force is a mysterious field that pervades the galaxy and unleashes the mental powers of the Jedi knights, allowing them to control objects with their mind. Lightsabers, ray guns, and even entire starships can be levitated using the power of the Force-and to control the actions of others. for example, the Force is a mysterious field that pervades the galaxy and unleashes the mental powers of the Jedi knights, allowing them to control objects with their mind. Lightsabers, ray guns, and even entire starships can be levitated using the power of the Force-and to control the actions of others.
But we won"t have to travel to a galaxy far, far away to harness this power. By 2100, when we walk into a room, we will be able to mentally control a computer that in turn will control things around us. Moving heavy furniture, rearranging our desk, making repairs, etc., may be possible by thinking about it. This could be quite useful for workers, fire crews, astronauts, and soldiers who have to operate machinery requiring more than two hands. It could also change the way we interact with the world. We would be able to ride a bike, drive a car, play golf or baseball or elaborate games just by thinking about them.
Moving objects by thought may become possible by exploiting something called superconductors, which we shall explain in more detail in Chapter 4 Chapter 4. By the end of this century, physicists may be able to create superconductors that can operate at room temperature, thereby allowing us to create huge magnetic fields that require little power. In the same way that the twentieth century was the age of electricity, the future may bring us room-temperature superconductors that will give us the age of magnetism.