The Tribune, Chandigarh, India

Peering into the soul
William Saletan

Years ago, Woody Allen used to joke that he’d been thrown out of college as a freshman for cheating on his metaphysics final. ``I looked within the soul of the boy sitting next to me,’’ he confessed.

Today, the joke is on us. Cameras follow your car, global-positioning systems track your cellphone, software monitors your web surfing, X-rays explore your purse, and airport scanners see through your clothes. Now comes the final indignity: machines that can look into your soul.

With the aid of functional magnetic resonance imaging (fMRI), which tracks the activation of specific parts of the brain, neuroscientists have been hard at work on Allen’s fantasy. Under controlled conditions, they can tell from a brain scan which of two images you’re looking at. They can tell whether you’re thinking of a face, an animal or a scene. They can even tell which finger you’re about to move.

But those feats barely scratch the brain’s surface. Any animal can perceive objects and move limbs. To plumb the soul, you need a metaphysician. John-Dylan Haynes, a researcher at Germany’s Bernstein Center for Computational Neuroscience, is leading the way. His mission, according to the center, is to predict thoughts and behaviour from fMRI scans.

Haynes, a former philosophy student, is going for the soul’s jugular. He’s trying to clarify the physical basis of free will. ``Why do we shape intentions in this way or another way?’’ he wonders. ``Your wishes, your desires, your goals, your plans — that’s the core of your identity.’’ The best place to look for that core is in the brain’s medial prefrontal cortex, which, he points out, is ``especially involved in the initiation of willed movements and their protection against interference.’’

To get a clear snapshot of free will, Haynes designed an experiment that would isolate it from other mental functions. No objects to interpret; no physical movements to anticipate or execute; no reasoning to perform. Participants were put in an fMRI machine and were told they would soon be shown the word ``select,’’ followed a few seconds later by two numbers. Their job was to covertly decide, when they saw the cue, whether to add or subtract the unseen numbers. Then they were to perform the chosen calculation and punch a button corresponding to the correct answer. The snapshot was taken right after the ``select’’ cue, when they had nothing to do but choose addition or subtraction.

Until this experiment, which was reported last month in Current Biology, nobody had ever tried to take a picture of free will. One reason is that fMRI is too crude to distinguish one abstract choice from another. It can only show which parts of the brain are demanding blood oxygen. That’s too coarse to distinguish the configuration of cells that signifies addition from the configuration that signifies subtraction. So Haynes used software to help the computer recognise complex patterns in the data. To dissect human thought, the computer had to emulate it.

Each participant took the test more than 250 times, choosing independently in each trial. The computer then looked at a sample of the scans, along with the final answers that revealed what choices were made. It calculated a pattern and used it to predict, from each participant’s remaining scans, his or her decisions in the corresponding trials. Haynes checked the predictions — add or subtract —against the answers. The computer got it right 71 per cent of the time.

I know what you’re thinking: Why would anyone want a machine to read his mind? But imagine being paralysed, unable to walk, type or speak. Imagine a helmet full of electrodes, or a chip implanted in your head, that lets your brain tell your computer which key to press. Those technologies are already here. And why endure the agony of mental hunt-and-peck? Why not design computers that, like a smart secretary, can discern and execute even abstract intentions? That’s what Haynes has in mind. You want to open a folder or an e-mail, and your computer does it. Your wish is its command.

LA Times-Washington Post

THIS UNIVERSE
PROF YASH PAL

Would you please tell what is global warming?
Living on the surface of the earth we receive most of our energy in the form of light and heat from the sun. Even fuels, such as coal and oil, we use are believed to be fossils of earlier life on the planet. The only energy that we do not owe to the sun is that which is produced by nuclear reactors. A thin layer of atmosphere surrounds our planet; this is mainly oxygen, nitrogen, some carbon dioxide, a little water vapour and a trace of noble gases. The total mass of air over a square centimeter of the earth at sea level is about one kilogram. Every one knows that we need this atmosphere. We would not be alive if we did not have any oxygen

to breathe. Also we would not have any clouds, rain, the blue skies or rainbows without our atmosphere. Even if we could manage without these we would have to contend with unbearably hot days and impossibly cold nights. The atmosphere acts as a blanket and as an equalizer. (Even though this consideration is not central to the point we are discussing we should keep in mind the incontrovertible implication of an atmosphere-less planet. Our planet would be scarred with meteor craters, very much like the surface of the moon, mercury or mars.) The function of a normal blanket is to insulate. The effect of the atmosphere is somewhat different. As mentioned earlier the earth receives energy from the sun mostly as visible light and near infrared. These are the wavelengths where the sun at a surface temperature of about 6000 degrees emits most of its radiation. We all know that air is nearly transparent to visible light. Therefore a large fraction of the solar energy falling over the top of the atmosphere makes its way to the ground. If all this energy were absorbed and retained by the earth its temperature would rise to thousands of degrees. This cannot happen because a warming earth reaches an equilibrium temperature at which it scatters or radiates into space as much energy as it receives from the sun. The temperature at which the earth’s surface is maintained depends on the properties of the atmospheric blanket. Visible light comes down relatively uninterrupted. The temperature of the earth is in the neighbourhood of 30 degrees Celsius. At this temperature the emitted radiation lies at far infrared wavelengths. However this radiation cannot pass out of the atmosphere uninhibited. Molecules like the carbon dioxide, water vapour and others that have three or more atoms have energy levels that allow efficient absorption of wavelengths at which the earth radiates. This increases the temperature close to the ground to a level where the net escape of energy is equal to the rate at which energy is received from the sun. It is then clear that if the concentration of carbon dioxide or other multi atom molecules increases the absorption of radiated energy would increase with the result that the equilibrium temperature would also go up. We have started increasing the concentration of carbon dioxide in the atmosphere since the industrial revolution at an ever-increasing rate. This has been measured. Recent indications are that the average temperature of the earth has also started moving up. This is global warming. The temperature does not have to go up by five or ten degrees for significant changes on the earth. Ocean temperature increasing by a few degrees would expand their height much like that of the mercury column in a thermometer. This can raise the sea level enough to submerge many coastal areas. Should the warming result in the Antarctic ice sheets slipping into the sea the rise in the sea level would be much more catastrophic. If such things happen in a few decades it should not be considered as a slow change. Whole countries cannot move away that quickly. Even if they try it would be unsettling in the extreme. Global warming might change precipitation and demand entirely different cropping patterns. We are talking about serious business. Relatively small changes can produce large effects. We should keep remembering that the surface temperature of the Venus is hundreds of degrees Celsius. Perhaps it got caught in a process of runaway global warming.

Commonest evidence of the physics of global warming is seen by all of us when we step into a car that has been sitting in the sun with its windows rolled up. The radiation from the inside is not allowed egress as easily as the sun’s radiation can go in. Glass windows act much like carbon dioxide in the atmosphere.