What can we know about the world of atoms?

At the end of April 1926, the then only twenty-five-year-old Werner Heisenberg held a lecture at the prestigious Physics Symposium at the University of Berlin. The title of his speech had attracted all the eminent German physicists of the time, among others the already very famous Albert Einstein. In front of this demanding audience, the young physicist presented a new theory on the behavior of atomic particles that he had recently developed in cooperation with his other young colleagues. Even though everyone was interested to hear what kind of theory these young scientists had come up with, the lecture turned out to be quite unusual.

At the time, what physicists discussed at great lengths was how to explain the unusual behavior of microscopic particles which sometimes acted as usual particles, and at other times as waves. How to explain this strange double nature of atomic particles was the question to which nobody could provide a satisfactory answer. What was so unusual about Heisenberg’s lecture was that the young physicist seemed to be trying very hard not to even mention what supposedly happened inside the atoms themselves. He limited himself strictly to demonstrating the mathematical theory of calculating the predictions of the results of experiments on atoms, without giving any explanation of what actually happened in the world of atoms. That was because the physicist himself did not know the answer to the burning question of physics of that time, but he had succeeded in finding a way to calculate the predictions for the results of atomic particle experiments.

After the lecture, Einstein himself came up to the young physicist and invited him to accompany him on his way home. Of course, Heisenberg was ecstatic about the offer. He was certain that Einstein would be very pleased with his approach to the problem of quantum physics, as this field of science had been named, because he had used a similar approach when he had been working on his theory of relativity. Just as Heisenberg intentionally avoided delving into what actually happened inside the atoms and restricted himself to the characteristics of atomic activity that could be measured and calculated, Einstein, some decades earlier, when dealing with the question of time and space had systematically limited himself to individual readings and direct measurements, leaving the deeper questions of what time and space actually were on the side.

“It is the theory that determines what can be observed”

The innovative approach with which Einstein restricted himself to what could actually be measured, temporarily leaving other questions aside, enabled him to start a veritable revolution in physics and to completely redefine the discussion about the nature of time, space, energy and matter. Heisenberg hoped that, by applying this method to the world of quantum particles, he could make a similar breakthrough in understanding nature as his idol had succeeded in doing at the beginning of the twentieth century.

Surprisingly, Heisenberg’s idea to avoid establishing models of what was really going on in the world of atoms and limit his work only to what he could actually observe did not please Einstein at all. It is interesting that his doubts did not stem from the concern that a strictly mathematical theory was insufficient to explain what happened in nature, but from his opinion that even when relying merely on physical experience, which is directly accessible, one should still apply different scientific theories when, for example, explaining a movement registered by a measuring device as the result of the collision of an atomic particle into the instrument. Einstein claimed that explaining even completely direct physical experiences requires the application of a number of different theories and that such a thing as the direct observation of the world, completely independent of any theory, can not exist.

As Heisenberg later wrote down in his memoirs, one of things Einstein said was: “It is fundamentally wrong to attempt to confirm a theory merely on the basis of observable quantities. In reality, what is true is quite the opposite. It is the theory that determines what can be observed. /…/ Only theory, that is the understanding of natural laws, allows us to link an experience to its cause.”

Heisenberg defended his newly discovered theory of quantum mechanics, but he and Einstein quickly reached the conclusion that they still knew far too little about what went on in the world of atoms to reach any important conclusions. It was also apparent that, because of the great age difference – Einstein was almost twice his younger colleague’s age – they were unable to have a completely relaxed discussion. In the following years it was Niels Bohr, an older Danish physicist closer to Einstein’s age, that took over the debate on the important issues raised by the new field of quantum physics and also became one of the key scientists that greatly contributed to the exploration of this new physics of the world of atoms. The discussion between Einstein and Bohr is believed to be one of the greatest intellectual debates of the twentieth century. It lasted almost thirty years, from the 5^th Solvay Conference until Einstein’s death in 1955.

Einstein would then become a little upset …

In September 1927, at the Como Congress in Italy, Bohr presented his principal idea for explaining the world of atoms to his colleagues. Einstein was not present at this meeting, but he supposedly did not miss much, because Bohr’s lecture, according to those that were present, was so condensed that nobody could actually understand it very well. Today, however, this very lecture is considered to be one of the milestones in the history of physics, because it established the central idea around which the interpretation of quantum mechanics is focused, and still has a place in many physics textbooks today.

According to Bohr, physics can only base its theories on what we can say about the world and not on what the world itself really is. While Heisenberg ignored the problem of how to imagine the world of atoms, Bohr made another step forward and showed that one can get a relatively good idea about what is going on by combining the two opposing models explaining the nature of atoms. Bohr’s principal idea was that the world of atoms can not be described using one consistent model only, but by applying several together.

Naturally, Einstein strongly disapproved of Bohr’s idea, so he decided to put all his efforts into revealing a paradox between his theory of relativity and the claims made by the new, quantum physics. This is how Heisenberg remembered the events that took place at the 5^th Solvay Conference in Brussels in 1927: “Everybody was staying at the same hotel. However, it was not in the conference hall where the most passionate debates took place, but during meals in the hotel restaurant. /…/ The discussion often began early in the morning when Einstein would explain some new theoretical attempt which, according to him, invalidated the principle of non-specificity. Of course, everyone immediately started to analyze what he had proposed, and on the way to the conference room, to where I usually accompanied Bohr and Einstein, we had already clarified the first question and claim. Throughout the day we continued to discuss this at length and, before the evening, we had come far enough that at dinner Niels Bohr could already prove to Einstein that even in the example that he had suggested, it was impossible to avoid the principle of non-specificity. Einstein would then become a little upset, but by breakfast the next morning he would already have prepared a new theoretical test, even more complex than the previous one. By the evening, however, this test proved to be no more resistant than the first one, and the game would continue for another couple of days.”                

Can we learn more about atoms?

In 1930, Einstein arrived to the 6^th Solvay Conference with an elaborate and carefully designed theoretical test which he had prepared in advance and was supposed to prove that something was wrong with quantum mechanics. However, after a detailed analysis, Bohr quickly discovered that this time Einstein had failed to take into consideration the effect of his own general theory of relativity which had caused him to think he had found an error in quantum physics. If he would have taken the general theory of relativity into account, there would be no inconsistency.

After another failure Einstein no longer tried to prove that quantum mechanics itself was incorrect, but went at the problem from a different angle. He tried to prove that quantum theory was incomplete. In other words, he wanted to show that, in theory, it would be possible to say more about atoms themselves than quantum physics would allow. He wished to show that atomic particles had characteristics that can not be explained by quantum physics, but could possibly fit into a different theory and could be measured as well.

He needed no less than seven years to find a way that could theoretically prove that quantum physics was an incomplete theory which did not take account of all the characteristics of atomic particles. In 1935, he and his colleagues Boris Podolsky and Nathan Rosen, now already at Princeton, United States, published a paper in which they described a theoretical experiment to prove that nature has to know more about itself than what the equations of quantum physics can reveal.

When Bohr found out about Einstein’s new paper, he immediately dropped everything he was doing and dedicated himself to finding an error in Einstein’s theoretical experiment. Three months later, an article with Bohr’s answer to Einstein was already published. Nevertheless, Einstein did not agree with Bohr’s defense of quantum physics and their debate came to a standstill. Both were certain that it was more or less a matter of a “philosophical” debate. A few decades later, though, another physicist, while reading Einstein’s paper, got the idea how it would be possible to experimentally verify whether quantum physics was a complete theory or not. But that is another story.

Why desert comes last

When it comes to doing a great number of things, it is difficult to imagine doing them any other way than how we are used to. It feels as if our most deeply rooted habits were something natural and predetermined. The same goes for preparing and consuming food. Many would be surprised to learn that the order of courses in a meal as well as the established combinations of tastes in an average European meal today have its origins in the middle of the seventeenth century. It was at that time that the wealthier Europeans made significant changes to their eating habits, habits that have been taken for granted to this day. The reason for changing the established diet was a new scientific theory about how digestion works and what healthy nutrition really means.

Nature as one big kitchen

Since ancient times, people have been aware of the fact that their health depends greatly on the food they consume. In the time of the High Middle Ages and Renaissance there was a rule defining the health of an individual as a state in which his bodily fluids are in just the right proportions. Food was an important factor in maintaining physical balance as the doctors of the time could not rely on many methods with which the balance between bodily fluids could be regulated. When someone was severely ill, they would try to reestablish the balance within the body by controlled blood-letting. That is why the wealthier part of the population that could afford to choose the kind of food they would eat, usually followed the principles of healthy nutrition.

According to ancient medical tradition which was based mostly on the works of the Hippocratic Corpus, Aristotle’s essays and Galen’s treatises, digestion was viewed as food being cooked inside the human body. Just as, in nature, the sun heats the earth so that plants grow from it and bear fruits, the inner flames of the human body were believed to “cook” the ingested food further until it was transformed into bodily fluids, while the remains were disposed of in the form of excrements which would then fertilize the earth, and the natural cycle could repeat.

The image of the cosmos as a big kitchen in which natural flames induce the growth of living nature and the circulation of matter was reflected in the image of the human body as a miniature version of this cosmic kitchen in which the inner flames cook the ingested food. According to this model of nature and man, the most frequent advice doctors gave their patients was that they should boil their food as much as possible, ensuring that their digestive mechanisms are put under less stress, and that they should consume balanced food. Of course, this balance should be viewed according to the way nutrients were classified at the time.

The theory of four elements

At the time, different types of food were classified according to Aristotle’s established theory of four elements from which the world was believed to have been created. Individual elements had been attributed corresponding characteristics. Fire was hot and dry, water was moist and cold, air was hot and moist, and earth was dry and cold. Food was classified in accordance with these four characteristics; pepper, for example, was put into the category of fire while melons, mushrooms and fish were classified under water. Because it was believed that the human body should ideally be moderately warm and moderately moist, meals were planned accordingly. A healthy diet meant eating food which came as close as possible to the ideal ratio of individual elements in the body.

The ideal meal was believed to be a sort of warm and relatively squishy porridge, because it contained all the characteristics that were supposedly best for the body. It is interesting that raw vegetables were, consistent with the principles of the time, considered unhealthy and appropriate merely as food for the poor. On the other hand, sugar was believed to be a very healthy nutrient and an ideal food additive which was also sold in pharmacies. Because it was relatively expensive, it was usually kept safe or even locked up in the kitchen.

New science, new menu

In the 17^th century, however, the diet of wealthier Europeans underwent a significant change. The ideals of nutrition had changed and so had advices for a healthy diet. In her books and articles, Rachel Laudan, a science historian researching the history of relations between science, medicine and nutrition, has come up with several convincing arguments which indicate that the change in the eating habits of the rich around the year 1650 happened mostly because of new scientific discoveries. The main reason for these changes was a new scientific theory about how human digestion worked and how, in nature, one substance changed into another. If scholars before mostly compared the happening in nature and the human body to the process of cooking, which supposedly causes substance to change, the central natural process now became fermentation. In the most general terms, fermentation is a chemical process in which carbohydrates, like sugars, are transformed into alcohol and acids. With the fermentation of yeast, for example, one can produce wine, beer and vinegar. With the fermentation of lactic acid bacteria, milk changes into yogurt and other dairy products. Fermentation also contributes to the bread rising process, releasing carbon dioxide which leavens the dough by creating the bubbly structure typical of bread.

The chemistry of tastes

Scholars that, a few centuries ago, studied the branch of science today known as chemistry, used fermentation and distillation to isolate individual key ingredients of plants and search for new active healing ingredients. Because fermentation was present throughout nature as well, the theory was quickly established that the essence of human digestion was not some extended process of cooking food that takes place in the stomach, but the process of fermentation itself.

The system of food classification was quickly adapted to the new theory of digestion. Aristotle’s four elements with their usual characteristics were replaced by a system of classification according to three new ideals of pure substances which were first introduced in chemistry. The three ideal substances were salt, oil and quicksilver. However, these are not to be understood in the modern sense of the words, but the more (al)chemical sense, pertaining to the roles of these substances in the processes of fermentation and distillation. The chemists of the time discovered that in the process of distillation substances are usually separated into three parts: volatile liquids, “oily” substances and solid residues.

Sugar becomes poison

Oil was the term used to designate substances that did not evaporate during the boiling process, in contrast to alcohol which was classified as one of the “quicksilver” substances. Among the food items that could be found in the kitchen, butter, lard and olive oil were the closest to the “element of oil”. Apart from regular salt, flour and similar solid substances were part of the “salt” group. The typical representatives of the “quicksilver” group were vinegar, wine and other alcoholic beverages, as well as certain flavors of meat and fish. With the new division of food, oils especially gained importance, becoming the key ingredient of a variety of sauces. The new food classification system caused a noticeable change in eating habits.

As for sugar, doctors began to realize that it was far from the ideal nutrient it was once believed to be. They discovered, for example, that it damaged teeth, and was also found in the urine of several patients which was later attributed to diabetes. According to the new division of nutrients, sugar was no longer believed to be an ideal type of food, and some doctors came close to describing it as poison. That is why during the last few centuries our main courses have no longer contained excessive amounts of sugar, and sweets have only been consumed in small quantities at the end of the meal.

Cell police

Once upon a time, long ago when our planet was still uninhabited by plants and animals, single-celled organisms had developed an effective method to defend against the attacks of pesky viruses that even then caused epidemics. It is only a few years ago, that scientists discovered that the same mechanism single-celled organisms had developed as a defense system against viruses several millions of years ago, is still active in most living beings inhabiting Earth today, including people. A deeper insight into the workings of this mechanism could enable us to successfully treat severe diseases. That is why it came as no surprise when the 2006 Nobel Prize in Medicine was awarded to the very scientists, who had, several years earlier, discovered how this primeval, but still very effective cell mechanism built into most of our planet’s living beings worked.

Like a country with strict regulations

The living cell is a highly complex mechanism in which many precisely planned and controlled chemical processes take place. It could be compared to a country in which everything happens strictly according to regulations. Carefully stored in the central palace of the country is a massive collection of laws and regulations containing the exact instructions for everything that may happen within its borders. There is only one version of the “code”, so it can never leave the central palace. However, the inhabitants of the country need precise instructions in order to produce anything, so there is a large number of scribes working in the palace, constantly transcribing recipes for creating individual products from the code and sending them around the country. When one of these copies of instructions is delivered to a citizen of the country, he immediately goes to work. If the citizen who receives the instruction were a cook, he would simply make the dish as described in the recipe.

Using the metaphor of a country where everything happens in accordance with strict regulations, we have roughly described the way a living cell functions. The unique code containing all the information necessary for the functioning of the country is of course a metaphor for the genetic code which is carefully stored in the DNA molecule and never leaves the cell nucleus. The copies of instructions for building individual products are molecules of messenger RNA (mRNA) that carry information from the nucleus to different parts of the cell, while the diligent scribes making the copies of the code in the central palace are enzymes called RNA polymerases (the 2006 Nobel Prize in Medicine was awarded for the research of this very enzyme).

The copies containing the recipes, or molecules of mRNA, can easily leave the cell nucleus and move freely throughout the cell. As we have mentioned, when the recipe reaches a cook, he reads it and makes whatever the instructions are for. In actual cells, the cooks that use recipes to make different dishes are called ribosomes. Their job is to use the information contained in the messenger RNA to build a certain protein which, in turn, performs specific tasks in the cell. This is how most of the cells of all living beings on Earth work.

When a cell is attacked by terrorists

However, a country in which everything happens strictly according to regulations does have its faults. Evil terrorists can smuggle in their own recipes which are not copies from the central palace code. When a cook happens to get such a “terrorist” recipe, he has no way of telling that the instructions did not come from the country’s code. That is why he has no difficulties with following the terrorist recipes. Unconsciously, he works for the enemy of the state and can, without even knowing it, build a deadly murder weapon. These evil terrorists that infiltrate cells and abuse their mechanisms are known as viruses. They are extremely cunning and well adjusted to living this pirate’s life.

Anti-terrorist squads

In response, cells had quickly developed a method to fight such malevolent terrorist attacks. When terrorists enter a cell they first try to multiply or, in the terms of our metaphor, to produce as many recipes for creating a murder weapon as possible, and spread them throughout the cell. However, when they multiply, they spend a few moments in the form of a double RNA helix. One could say that for a short fragment of time the recipe and its copy remain attached. And it is in this very moment, when the instructions and its copy are still glued together, that a cell can detect the recipe as potentially dangerous and sends its special police units after it. The anti-terrorist cell police does not only destroy the instructions with the copy attached, but also starts to eradicate all other recipes in the cell which contain the same instructions.

The technical term for anti-terrorist units that can detect recipes carrying their own copies and destroy them is RNA interference or RNAi. For their fundamental contribution to understanding the functioning of the mechanism of cell resistance against viruses, which is also an effective mechanism for controlling the expression of individual genes, the Americans Andrew Fire and Craig C. Mello were awarded the 2006 Nobel Prize in Medicine.

The petunia mystery

As is the case with most important scientific discoveries, the first encounter with the RNAi mechanism was completely accidental. In 1986 a small California biotech company wanted to create a special flower. They tried to create a petunia that would have extremely vibrant violet petals. They knew which gene was responsible for the production of violet color, so they tried to enhance its expression by injecting more instructions for creating violet color into the plant’s genetic code.

The results of the experiment were surprising. Instead of becoming even more intensely violet, the flowers of this genetically modified petunia were now completely white. Naturally, the researchers thought they must have made some kind of mistake, but after carefully reviewing the entire process found out that there was no error. The answer to the question of why the petunia flowers turned completely white and not more violet than usual became the mystery that many brilliant minds spent more than a decade solving.

Unlimited anti-terrorist awareness

Today, we know that when the new genes were being injected into the plant, the RNAi mechanism was turned on, recognizing the presence of the artificially added genes as an enemy virus attack and destroying all recipes similar to those that scientists had tried to infiltrate into the cell. Because the newly added recipes were identical to the ones that the cell had already produced itself, the cell’s anti-terrorist squad started to destroy both the artificially injected recipes and the ones that had been naturally transcribed by the scribes working within the cell nucleus. The cell police was successful in destroying all the recipes for producing the color violet, so the petals turned out white.

For now, the discovery of the RNAi method has proven to be useful mostly in scientific research of individual genes, but it will soon become important in the treatment or at least in the diagnosis of various severe diseases. The cell’s anti-terrorist squads can be taught to destroy specific recipes within cells which contain the instructions for the production of individual proteins. A number of diseases occur exactly because cells produce an excess of a specific cell product. Different methods are already being tested to use the RNAi mechanism in treating the various forms of hepatitis, Huntington’s disease and AIDS as well as some forms of cancer.     

Who really makes the decisions in our minds?

Researchers invite you to take part in a memory experiment. Your task is simple. You have to remember a seven digit number and transfer it from one end of the building to the other. You are given your task in the reception room, then you go down the hall towards the other end of the building where you have to communicate the number you had been told. While you are walking down the hall, struggling mentally not to forget the number, one of the participants in the experiment suddenly stops you and, as refreshment, offers you the choice between a delicious chocolate cupcake and a fruit salad. You pick one of the items available and continue your way to the designated room.

It is only after you have successfully passed on the message that the researchers tell you they were not even interested in your memory, but in your decision making. The main purpose of the experiment was to find out whether you would choose the cake or the fruit. The participants in the experiment were not all given equally difficult tasks. Some had to use their memory to pass on a seven digit number while others were only given a two digit number. The most unusual thing, though, was that a larger percentage of those who had been given the more demanding task chose the cake instead of the fruit salad. 59 % of all the participants who had to carry a seven figure number in their minds chose the cake, while only 37 % of those who were asked to pass on a two figure number opted for the chocolate dessert.

Do people really make rational decisions?

This and many similar experiments in which scientists observe people’s decision-making processes in different circumstances indicate that our decisions are not nearly as autonomous as it may seem. Since the early Greeks, it has been believed that people were essentially rational beings that make their decisions on the basis of careful consideration supported by arguments and logical analysis. However, the latest findings suggest that this thousands of years old presumption might not be completely true.

Let us mention another recently conducted experiment. In his book, Predictably Irrational: The Hidden Forces That Shape Our Decisions (Harper, 2008), the American economist Dan Ariely describes his analysis of an apparently absurd offer for the subscription of The Economist magazine. The potential subscribers had three choices at their disposal: a cheaper subscription to the digital edition of the magazine, a more expensive subscription to the printed edition, and a third option which cost the same as the printed edition, but offered both the printed and the digital editions together.

Naturally, of all the people in the test group nobody decided to choose the subscription to the printed edition only, because he could get both the printed and the digital editions for the same amount of money. So why did the advertisement even include the option for subscribing to the printed edition only when, for obvious reasons, nobody would choose it? The answer to this question is hidden in the results of the second part of the experiment in which the potential subscribers were not offered the third option and could only decide between the digital edition and the combined subscription. Of 100 students who took part in the first part of the experiment 16 chose the digital subscription, 84 chose the double subscription and nobody decided to choose the subscription to the printed edition only. However, when just two options were available, 68 participants chose the cheaper digital edition while only 32 decided to go for the more expensive double edition.

The result of including the seemingly absurd additional offer for the printed edition was that a substantially greater number of people decided to choose the more expensive option. The offer for the subscription to the printed edition only was listed in order to create confusion in our brains and convince us to opt for the more expensive subscription, because it would seem to be a better bargain. The reason for deciding differently in each of the two cases is that the brain usually does not assess the absolute values of the offers, but decides on the basis of their relative values. The brain only wants to know how one offer compares to other available offers.

In fact, the brain is very bad at attributing absolute values to things. It is much more successful in comparing the values of individual offers and this is where it can be most easily fooled. That is also one of the reasons that, on their menus, restaurants usually offer a very expensive dish that nobody would actually order. The purpose of this dish is to make the visitors of the restaurants feel better when they order a cheaper dish, because they feel like they had made a good deal.

Which part of the brain can be trusted?

Scientists are learning that in our brains people have two separate systems for making decisions. The first is specifically human and is based on the rational analysis of a given situation. With it, we analyze all the available options until we have found the best one. The second decision-making system has been inherited from our animal predecessors and works on a subconscious level. Even though our brains carefully analyze the options and scan through the smallest of details, we are not really aware of this process, but simply feel that a certain choice is more attractive than the others.

This second system of decision-making informs us of its preferences through feelings or emotions that affect us when we are considering an individual offer. If an option is extremely unfavorable we can feel somewhere in our bellies that our body is telling us to decide otherwise. Nevertheless, both decision making systems have their good and their bad sides. The secret of deciding correctly is to know when to rely on your mind and when to follow your feelings.

A Dutch scientist called Ap Dijksterhuis observed how people made decisions when buying furniture at an Ikea store. He found out that the more time the customers spent deciding what to buy and analyzing their options, the less happy they were with what they bought later on. In a report on this unusual research that he published in Science magazine a couple of years ago, he wrote that when it came to complex decisions that required analyzing a great amount of data, people were making much better choices when they relied on their instincts. It was only with the easier choices that a logical analysis turned out to be the better strategy.

The latest research suggests that to make good decisions one should do exactly the opposite of what tradition or common sense tell us. Conventional wisdom teaches that when dealing with simple decisions, we should not rack our brains about making the right choice, but trust our instincts, while with more difficult decisions, we should put our minds to it and decide on the basis of a thorough analysis. Dijksterhuis and other scientists came to the conclusion that the best strategy was exactly the opposite.

The problem with the analytical part of our brains is that it can only process a limited amount of information at once. According to various measurements, a human being can rationally process only five to ten independent bits of data at the same time. When the amount of information exceeds this number, the analysis becomes unreliable, as the brain begins to generalize, which can cause a bit of data important for the final decision to get lost. When there is too much information, a person trying to decide on the grounds of rational analysis often makes the wrong or less than ideal decision.

In the first part of the experiment, people who had to pass on a seven digit number were more inclined to choose the cupcake because the rational part of their brains was occupied with remembering the number, so they left the decision to their feelings which made them pick the cake. The participants who only had to carry two numbers in their minds were left with enough space in their “brain processors” to think about the options rationally and chose the healthier fruit salad.

Ap Dijksterhuis believes that the transition from the rational to the instinctive system of decision-making can already occur when we are dealing with a problem that has more than four different variables. The general rule that his research has lead him to is: when making decisions that do not involve a large number of parameters that need to be taken into consideration, decide rationally; when it comes to complex decisions, trust your instincts.

With difficult decisions like buying a new car, an apartment or furniture, the best strategy Dijksterhuis suggests is to first collect as much information as possible, then let the brain to process it for a while. It is best to leave the decision-making at least for one day and sleep on it. Even if we are relying on our instincts, it is now much more likely that we will chose correctly and be happy with our choice in the long term.

How babies learn languages

It is well known that someone who had been raised in Japan and whose mother tongue is Japanese can not tell the sound r from the sound l. If such a person were to hear the sentences He likes to read and He likes to lead taken out of context, he would most likely not be able to tell them apart. To him, both sentences would sound the same, because in his early youth his brain was adapted to the use of the Japanese language in which there is no difference between the two sounds. Similar peculiarities in perceiving the differences between sounds also occur in other language environments. The Spanish and the French distinguish the sounds b and p in a different way than the English. What sounds as a b to a Spanish person, would sound as a p to an English person. In contrast, a Thai person would distinguish three different variations within the sounds that we perceive only as b and p.

The structure of potential variations or phonemes that an individual can tell apart within the range of all possible sounds is stored in the brain very early in life, and can not be changed with learning later on. Once an individual acquires a language, he is forever condemned to distinguishing only between the sounds that exist as variations within his language environment.

Suckling on consonants

We all know little children can easily learn the language of the environment in which they are being raised, while later one has to try much harder to learn a new and unfamiliar language. Why is there such a difference? Would it be possible to activate the ability of spontaneous language acquisition later in life? Questions about how the brain learns to understand and produce a language have always fascinated scientists who have been involved in the active research of this field of science.

Because it is impossible to ask babies whether they can tell the difference between, for example, read and lead, scientist have come up with all kinds of alternative methods to test infants whether they can differentiate between individual sounds and find out when they start to lose this ability. They created an imitation of a breast which does not produce milk while the baby suckled on it, but sounds. The more the babies sucked the more distinct sounds were being produced, and the children were almost as pleased by this as if they were actually getting milk.

However, if the children could only draw a single, repeating sound out of the speakers, they would eventually grow tired of the activity. When the sound would change, though, they would start sucking more actively again. It was this very change in the intensity of sucking which revealed that children could tell the difference between two sounds, otherwise such a reaction would not have occurred at all. This made it possible to observe whether little children could differentiate between the sounds r and l, despite the fact that they were being raised in the Japanese language environment.

At first, scientists assumed that the children would not be able to detect the subtle differences between individual sounds, but that they would gradually learn to do so while they grew up. Surprisingly, they discovered that in fact the truth was just the opposite. Even month-old babies from the English language environment were able to distinguish between all the phonemes that were characteristic of the English language. These babies had already developed a framework of the English language within which they could tell the difference between all the different r sounds and all the different l sounds, but they could not detect the differences within both individual groups of sounds, even though they were pronounced by different speakers.

The surprises kept on coming. When they tested babies from other language environments, they found out, for example, that also Mexican children of the Spanish language environment could easily distinguish between the different sounds of the English language. Similarly, Japanese babies had no difficulties with telling apart the sound r from the sound l, despite the fact that their parents were unable to do so themselves.

Babies can speak all languages

Infants can distinguish between phonemes of all the existing languages of the world even when they had never heard a certain language before. It makes no difference whether the sounds are French, English, Chinese or Slovenian, infants have no difficulties with telling them apart regardless of who pronounces them, be it a man, a woman or a child. Babies have an inherent aptitude for learning languages. In fact, they have a sort of universal talent for learning any of the approximately 6000 languages that still exist today.

It is also important to emphasize that a child does not merely distinguish individual sounds like a computer detector which can be set to detect the difference in the frequency of two consecutive sounds. Children are able to correctly categorize sounds by classifying them into groups on the basis of which words are formed. When born, every child functions like a sort of universal receiver that can acquire any language. The key question that arises is why babies, which are born as universal linguists, later become specialized in their language only, and lose the ability to differentiate between the phonemes of other language environments.

Because the breast imitation test was not as effective with older infants, scientists have developed other methods to monitor their responses to different sounds after they have reached six months of age. Today, electric sensors are used for this purpose, attached to the child’s head with a sort of hat that measures minute differences in brain activity, and can detect when the child notices or fails to notice a difference between two phonemes.

In Japanese children, researchers discovered that they could easily distinguish between the English r and l at the age of seven months, but would lose this ability only three months later. Nine-month-old Japanese children could no longer tell the difference between the two sounds while American children of the same age actually became more susceptible to this difference. A similar research conducted on Canadian children revealed that at six months of age they were capable of distinguishing between phonemes of exotic languages which their parents and their twelve-month peers could no longer tell apart. After their first birthday, a child’s brain no longer has the universal flexibility to acquire any language, but has already been adapted, so it can absorb the language of its environment more easily.

With different research methods, scientists have learned that the loss of the universal ability to differentiate between phonemes also occurred on a comparable level in deaf children when they were being communicated with in sign language. All children starting to learn a language lose their universal ability at this age, but become much more specialized in distinguishing between the phonemes of their language.

Research has shown that children, once they have lost their universal ability to differentiate between phonemes, begin to learn the language of their environment more rapidly than their peers who remain sensitive to the sounds of more exotic languages for a longer period of time. This is so because communication is substantially easier when the brain only focuses on the differences important for conveying information and ignores everything else.

The time when children start losing the ability to tell apart the sounds of exotic languages approximately coincides with the time when they redirect their attention from sounds to words. That is when they start to get familiar with all the possible words in their language environment. Researchers have found out that nine-month-old children prefer listening to sets of sounds that correspond to the rules according to which sounds are usually combined in their language, even if they do not actually exist in the vocabulary of their language environment.

Direct contact is important

Also fascinating is the latest research that underlines the importance of direct personal interaction with the child learning a language. Scientists wanted to find out whether exposing children to an exotic language could prolong their universal ability to differentiate between phonemes.

Nine-month-olds were separated into four groups. For a couple of weeks, the children in the first group would occasionally play with Chinese teachers, who communicated with them solely in Chinese, even though the children had been raised in a strictly English speaking environment. The second group of children watched the Chinese teachers on video, the third group only listened to them and the fourth group had no contact with them at all.

What was interesting about the results of this experiment was that only the children who had been in direct contact with the teacher who communicated with them in Chinese preserved their ability to tell apart exotic phonemes later on. Their peers in the control groups, who had only listened to Chinese or watched the teachers on video, lost their ability to distinguish between phonemes just like the children who had no contact with Chinese at all.

Brain plasticity

Researchers of the brain have long believed that the brain, once fully grown, no longer changes. Only young brain was supposed to be plastic, as the ability to adapt is called in technical terms, and was believed to lose plasticity with time. However, research has shown that this belief is not completely correct.

Mapping monkey brains

At the beginning of the 20^th century when scientist started doing more detailed research on the distribution of different areas of the brain, responsible for the movement of individual parts of the body, they discovered it was not completely identical in all of the test animals. At first, they thought that the differences occurred due to their lack of precision, but it soon turned out that, even though the mapping of individual functions in the brain was by no means a simple task, the discrepancies were not the consequence of errors.

Researches wanted to map out the area of the brain which controls the movement of a monkey’s body, so they had to stimulate the brain part by part consecutively and write down which movement had been triggered. By stimulating a single point, for example, they triggered the movement of a finger while activating another point moved the entire hand. As brain tissue is not susceptible to pain, such mapping was not painful for the animals, but was most likely not very comfortable either.

More accurate measurements, or mappings, have confirmed that the maps of these areas of the brain were not identical in all the test monkeys. The point that triggered, for example, the movement of the hand was not located in the exact same place in all the test subjects. It turned out that the brain maps were specific to every individual monkey, much like fingerprints are specific to every individual person.

In addition, the maps revealed that the movements these animals performed together, in sequence, were controlled by neurons which were located close to one another in the brain. Scientists also discovered that the areas controlling the movements, characteristic of monkeys, occupied larger areas of the brain. If we were to illustrate this with an example from the human world, this would mean that a violinist has a substantially larger and more developed area which controls the fingers of the left hand than someone who has never played a musical instrument, an activity requiring great dexterity. Similarly, professional dancers possess a much larger area responsible for the movement of the feet than people who use their feet merely for walking.

Do brain maps change?

Of course, the question that quickly occurred was how these areas in the brain were formed and whether they could change during an individual’s lifetime. The more or less generally accepted belief of the scientists of the greater part of the 20^th century was that these areas were formed in early youth and could not undergo significant changes later. However, some skeptics decided to try and find out for themselves whether it was actually true that the map of a monkey’s brain would not change with time.

It was during time between the two world wars that researches already discovered that brain maps actually do change, most likely in proportion to the use of individual muscles. The movements executed more frequently were represented to a greater extent within the brain than the less frequent movements. However, these experiments went by relatively unnoticed because of the already established general belief that a fully grown brain could not undergo any further changes.

Despite the established belief, in the seventies, the American neurologist Michael Merzenich and his colleagues took on a more thorough research on how brain maps change under different external influences. At first, Merzenich was interested in finding out what the effect on the brain would be if a monkey would no longer receive sensory information from a specific part of the arm. He first accurately determined which areas of the monkey’s brain were responsible for processing the sensory stimuli from specific parts of the body. He then performed an operation that caused the monkey to lose feeling in one of its palms. After some time he mapped the monkey’s brain again and discovered that the area which had previously been responsible for the sensations in the thumb and its surroundings was not blank, but was now processing information from another part of the arm which still sent signals to the brain, because the nerves from that part of the arm had not been disconnected.

After this discovery he directed his research into less invasive procedures. He was curious whether the brain maps would also change if he taught the monkeys a new skill. He and his colleagues conducted a rather elaborate experiment in which they taught adult monkeys to use their fingers with great precision. The monkeys would get their reward only if they used the correct amount of pressure while handling a device. For them this was by no means a simple task, because they had to invest a lot of effort into training their fingers in order to get to the reward. It was no surprise that at the same time the researchers also discovered that the area in the monkey’s brain which controlled the movement of the fingers grew substantially with use.

How can the blind read?

The same characteristics that had been discovered in monkeys were later confirmed in people as well. There was an interesting research which focused on how the brains of blind people could process Braille. Scientists first found out that the area of the brain which processes the sensations in the reading finger of a blind person grows, which came as no surprise. What was more fascinating, though, was that the area responsible grows at the expense of the surrounding area, which the brain attributes to the remaining fingers. In a person who becomes skilled in reading with a finger, the area for processing the sensations in the principal reading finger grows, but does so at the expense of diminished space attributed to the remaining fingers.

Researchers stumbled on an even greater surprise when, using more modern methods, they discovered that during sleep, even in blind people, the area which is otherwise responsible for processing visual signals becomes active. This area was not expected to be active in blind people, as they do not receive any signals from their eyes, leaving this area in a passive state.

Nonetheless, it seems the brain is so adaptable or, in other terms, plastic, that an area not being used adjusts and becomes specialized in other tasks. In the mid-nineties, however, this discovery would not be easily accepted. The scientist that detected this particularity while observing the brain activity of blind people reading Braille encountered great difficulties when they tried to publish their findings. Science magazine refused to publish their work, because the editorial staff could not come to terms with how completely different parts of the brain could interconnect and work together, performing new tasks. In time, the article was published in the rival Nature magazine.

Later, new research actually revealed that the cooperation of the visual part of the brain has an essential role in the fluent reading of Braille. Someone who can read Braille fluently does not feel the dots on the paper at all, but directly perceives entire words, just as one reading ordinary writing is not conscious of individual letters, but takes in words and sentences as units of meaning.

In 2000, there was even a case, described in scientific literature, of a woman who has been blind since her early childhood and had learned to read Braille very well during her schooling. When she was 26, though, she suffered from a brain stroke in the area otherwise responsible for processing visual information. At first glance, such a stroke should not leave any significant consequences on a blind person, but this case seemed to prove otherwise. Even though the woman could still feel the dots of Braille under her fingers, she suddenly no longer understood their meaning. Her ability to read Braille was stored in the area that otherwise processes visual information, but in her case that had been damaged by the brain stroke.

Mental fitness

It has only recently become clear that even older brain is much more plastic or adaptable than it was first presumed to be. Nevertheless, the fact remains that the ability to adapt diminishes with time. Younger brains are simply much more plastic than older brains.

Michael Merzenich, one of the already mentioned pioneers in the research of brain plasticity, and his colleagues have already founded two companies offering professional help in overcoming difficulties in brain function. Scientific Learning helps children with learning disabilities. Using special computer games which are designed to develop specific parts of the brain that cause these children to have problems, the company has achieved impressive results.

These results have recently led to the creation of the Posit Science company which focuses on helping the older population. Using various mental fitness techniques it helps older people keep their brains in the same shape as they were in their best years.