Why Do I Need a Teacher When I’ve Got Google

that we ‘grow’ our brains, that brains learn through making and strengthening connections between brain cells. The making of connections contributes to what is called ‘grey matter’ in the brain. The strengthening is a process called myelination, myelin being a fatty substance that acts as an insulating sheath around the connections and helps make the passage of electrical impulses down these connections more effective. As this builds up in the growing brain, it is known as ‘white matter’ and it is something whose importance is only just beginning to be discovered by scientists.
    In between growing and consolidating though, there is the equally important process of neural pruning, the brain getting rid of connections it doesn’t use. More of that in a minute.
    How many years does this process of growing, wiring, pruning and consolidating take until we can say this is an adult, mature, human brain?Between 20 and 30. Remember that next time you are berating a 13-year-old for ‘acting like a child’. A 13-year-old acts like a child because they
are
a child and a child is not a ‘mini-me’. They are not small versions of us walking around doing bad things. They are a work in progress. And if they can’t get it wrong – and then learn to get it right under your professional care – where will they learn to get it right? In the words of
Scientific American Mind
:
    Society should not be fooled into thinking that a teen has the mental prowess of an adult just because he or she looks, and most of the time, acts like one.
    (
Scientific American Mind
09/2006)
    This maturation process, which has different rates according to gender but with both sexes reaching the finishing line about the same time, does not happen in a haphazard way. Rather it follows a pattern that appears to be hardwired into our genes with only serious malnutrition having any disruptive impact on it. It is a process that, like the filling up of a school hall on a training day, starts at the back and ends up at the front. And, as it can feel like on some mornings in a cold school hall, it is a process that takes years, something that has serious implications for the way in which we treat young people in schools.
    The first part of the brain that goes through this process of wiring up in the baby is at the back of the brain and relates to areas of the cortex to do with the senses, notably touch and sight. 1 This makes perfect sense if you think about babies ‘in the wild’. The sooner you can see and feel safety (your mother) or see and feel danger (not your mother), the more chance you have of surviving.
    The process of building, in over-abundance, grey matter in the part of the brain that deals with senses, known as the parietal lobes, is not finished until around the age of 12. Then the pruning starts. The growing of grey matter in the temporal lobes, an area of the brain associated with emotional behaviours and language, does not finish until around the age of 16 and, even then, there is still the growing of white matter and the pruning process to take place.
    So, from these early stages of myelination, what else does the young brain go through, especially in those critical adolescent years? Well, for a start, those mood swings and that newfound interest in loud music, extreme sports and people of the opposite, or indeed any, sex is not down to hormones. They are all down to the fact that the brain is a work very much in progress and, in the same way that you have to make a mess to build a house and for most of that time it is completely uninhabitable, thebrains, thoughts and minds of the average teen are equally a vast and dangerous building site where no-one would want to live.
    One of the biggest factors contributing to this is a process called hairy dendritic sprouting. During adolescence, there is a massive spurt in the number of connections in the brain, as if it is readying itself for one last gasp effort in preparing the soon-to-be adult carrying it around for whatever life may throw it at it. This is then followed by a significant period of neural pruning as the brain starts to mould itself to what is effectively going to be the life it’s going to lead (and remember that in the millions of years it has taken for this process to evolve, delaying the onset of adulthood by ‘having a year out’ is a recent addition).
    As the brain starts to ‘equip’ itself for the years ahead, the teen years become a wonderful opportunity