‘When it comes to building the human brain, nature supplies the construction materials and nurture serves as the architect that puts them together.’  Ronald Kotulak[i] 

There has always been an aura of mystery about the inner workings of the brain. Over the years, experts have developed numerous theories about the nature of intelligence and its relationship with two powerful and sometimes conflicting forces: nurture and nature. Recently, researchers have made more progress than ever before, and the mysteries of intelligence have begun to unravel. For instance, scientists have now managed to count the numbers of brain cells within specific areas of the brain. Even more importantly, they have calculated the absolutely phenomenal number of interconnections that are made amongst these cells as they communicate with one another. In fact, scientists now have technology that allows them to look deep inside the living, functioning brain. This enables them to directly observe electro-chemical activity at the lowest levels, as thoughts and emotions are developed and processed. As the mysteries of the brain are unravelling, many long-held theories are being disproved and new ones developed. 

What is becoming increasingly clear is that the first few years of life are the most critical in terms of physical brain development. While the long-term interaction between nature and nurture determines the ultimate outcome, which is measurable in many different ways, the most significant period for the actual wiring of the brain is during the first few years of life. Typically, this process is nearly complete by the age of twelve. We now also know that there are various windows of opportunity during which the physical structures supporting certain essential capabilities, such as language, hearing, and sight, are laid down. Although the majority of these windows of opportunity occur between birth and the age of three or four, nature gives a child’s brain a second chance between the ages of about four and twelve. This means that an enormous responsibility lies in the hands of parents and educators to ensure that a child’s brain develops to its fullest potential. 

At the micro level, the human brain consists of about one hundred billion nerve cells, called neurons. These neurons can be thought of as very simple data processors, which work together to solve a particular problem as it is presented to the brain. Whilst individual neurons are far less capable than even a rickety old computer from decades ago, the human brain is still able to easily perform tasks that the largest, most expensive computers today find impossible to accomplish. Some everyday examples of these tasks include understanding spoken human language, identifying objects by sight, sound, smell, touch, and taste, and writing and understanding literature. Other examples are the ability to feel and respond to emotions, and to physically express these emotions through poetry, music, and art.  

The magic behind the brain’s power to handle these and other complex tasks is that the billions of neurons work together in concert, attacking problems in a massively parallel effort, by breaking them up into many thousands or millions of smaller pieces and then working on all those pieces at the same time. In contrast, computer processors today typically attack problems sequentially, one piece at a time, and accumulate the results until all of the pieces have been resolved. For the types of tasks described above, the computer’s method is far less efficient than the brain’s. In other words, the real power of the human brain lies in its ability to orchestrate the activities of billions of individual neurons working together, and the human brain can be likened to a symphony conductor. 

Fascinating Fact: Individual neurons operate at speeds measured only in the tens or hundreds of cycles per second, which are called Hertz. By contrast, 1970s-era processors operated at several million Hertz, whilst the latest members of Intel Corporation’s Pentium family of processors operate at several billion Hertz. Yet the human brain can still perform functions that are impossible for the most sophisticated computer – because it can orchestrate billions of neurons to work simultaneously on one task.  

Because the role of neurons is to process and then communicate vast amounts of information amongst themselves, they require a physical means to transmit and receive data to and from the other neurons. To support this communication, neurons develop dendrites for transmitting information and axons for receiving information from other neurons. As patterns of thought are first initiated and subsequently repeated, the participating neurons continually process and communicate. In doing so, they build stronger and more direct dendrite-to-axon pathways or connections – called synapses - to the other neurons that are participating in the task. In other words, with repeated stimulation, these connections become ever stronger and more established, and the brain has in effect ‘learned’ how to solve that particular problem. At this point, the brain is ready to undertake further learning. Interestingly, those neurons that do not generate synapses quite literally die off, so the old saying ‘use it or lose it’ could not be more true. 

At the macro level, the brain can be thought of in three parts: the brain stem, the limbic system and the cerebral cortex. These parts of the brain are divided again into specific areas, each with an individual and complex role to play. Some areas process information gleaned from the senses, whilst others process different aspects of our emotional responses. Some are responsible for laying down certain types of memory, whilst others help us to ‘read’ cues from other people and make appropriate emotional and physical responses.  

In order to make sense of the world, however, these individual, specialized areas of the brain must be able to communicate effectively with each other. In other words, the brain operates similarly at the macro/regional level as it does at the micro/neural level, relying on efficient communication amongst the regions to quickly resolve a task. To illustrate this point, all of us have at one time or another used our recollections of certain sights, sounds or smells to help us locate a specific, long forgotten memory. Perhaps the smell of a particular curry dish, for example, brings back memories of a joyous family gathering years ago, which celebrated some remarkable academic achievement. You remember how happy and proud you felt, wishing that night would never end. 

In locating this memory, your brain has used the information gathered by the olfactory nerves in the nose to match a unique pattern that it has stored identifying the smell of the curry dish. The patterns of other smells may have matched to one extent or another, but that specific curry smell matched most closely. The neurons and synapses representing this pattern then provided a map to the location in long-term memory of the pattern representing the family gathering. This memory then triggers those same happy and proud feelings, which you experience once again. As you can see from this, various sections of the brain may indeed have specialized functions, but they must still work together in order to provide what we somewhat loosely term ‘intelligence’. 

Although the sections of the brain are highly specialized, there is a degree of flexibility built into it. Until very recently, it was thought that the functions of the various areas of the brain were pre-programmed and inflexible, and that damage to one area of the brain caused, for example, by a stroke, would lead to irreparable loss of function throughout. The latest research, however, has shown that completely new wiring can actually be created, and that some areas of the brain can take on entirely new roles after physical damage has occurred to other sections. This flexibility of the brain is known as plasticity.  

If we envisage again the three primary parts of the brain, the brain stem is physically the lower part of the brain, which connects to the spinal cord. It is often called the reptilian brain, as it was quite likely the first true brain structure which evolved in higher order animals. Along with the cerebellum, the brain stem is primarily responsible for the body’s survival systems: for regulating our life support mechanisms such as heart rate and breathing, and for what is known as the ‘flight or fight’ response to perceived danger. Under stress, our basic survival instincts kick in and we produce chemicals that put the body under heightened alert. During these times of stress, higher order thinking becomes derailed, and, therefore, learning cannot take place effectively. It is for this reason that ideal learning environments are those that reduce a child’s stress level to its absolute minimum.  

Between the brain stem and the cerebral cortex is the limbic system. This is sometimes referred to as the mid-brain. The limbic system consists of several structures that manage our emotions and are responsible for some aspects of memory. The lower structures of the limbic system control our more basic and instinctive emotional responses, whilst the higher ones are responsible for making a more intellectual response to these emotions. For example, if you were to hear an unfair criticism of your work, the lower areas of the limbic system would deal with your more spontaneous responses such as blushing or shaking, whilst the higher areas would process the cultural and social issues that might help you to compose your expressions and make a measured response to your critic. This makes sense, as the higher parts of the limbic system are in closer contact with the cerebral cortex, where the most sophisticated thought processes take place. 

The cerebral cortex is the largest part of the brain, sometimes referred to as the thinking brain. Most high-level thinking processes take place here. It is physically separated into two sides, rather like two halves of a walnut. Many theories exist about the functions of these right and left hemispheres, and scientists are constantly discovering more about the left-right relationship. Sometimes people describe themselves as ‘left’ or ‘right’ brained. It is true that each individual has a dominant side, but to use these descriptions is too simplistic. It really does not matter which side is dominant, as the roles of the two hemispheres are interdependent, and communication between the two is needed for even simple tasks to be undertaken. For example, when listening to a piece of music, both hemispheres are hard at work. The left hemisphere is responsible for identifying familiar tunes, analysing and recognising sequences and rhythms, and identifying changes in volume. Meanwhile, the right hemisphere works on the ‘bigger picture’, whilst making pitch judgements and distinguishing between timbres.[ii] For effective learning, the right and left hemispheres of the cerebral cortex need to each do their own job and communicate effectively. The task of providing for and managing this inter-hemisphere communication belongs to the corpus collosum, which is like a super-highway through which messages travel. 

Our understanding of the brain is increasing continually, as scientists discover more about how we learn and develop. As information becomes available about the functioning and capability of the brain, we can become increasingly effective in helping children to learn and develop to their full potential. What is perhaps startling is the fact that altering a child’s environment and breadth of experiences can actually make a radical difference to his or her IQ level at a later age: 

‘Within a broad range set by one’s genes, there is now increasing understanding that the environment can affect where you are within that range…. You can’t make a 70 IQ person into a 120 IQ person, but you can change their IQ measure in different ways, perhaps as much as 20 points up or down, based on their environment.’ Dr. Frederick Goodwin,[iii] 

Scientists are helping to inform our practice more now than ever before. It is an exciting time to be involved with children’s learning, and the adventure is only just beginning.