Teenage years are trying times for kids as well as their parents. Nothing seems to make sense, and for a long time the strangeness of this phase of life had been attributed solely to hormones going wild. But the hormones are not the only major changes taking place. Modern imaging techniques have revealed that the brain undergoes a huge transformation during adolescent years and understanding these changes may help us understand teens better.
All done before it has even begun?
A few years ago I was looking for a preschool for my older daughter. At that time, one school emphasized that 95% of brain development happens by age 5. So if you don’t pick the right preschool and curriculum you could be dooming your child for life. I am paraphrasing of course, but you get my drift, right? Then I found the same subtle threats in a two minute advertisement for some chocolate malt flavored additive for milk. Does that mean that everything you can ever make of your life is determined by age five, long before you have any experience or proper decision making abilities?
Is your brain abilities limited entirely by how your parents cared for you in those first five years while they struggled with sleep deprivation and the terrible twos? That did not sit right with me.
So were these advertisements lying? Well, not exactly, but as it is with advertisements, they were misdirecting and playing on the insecurities of their target market, in this case parents. Some research on the subject indicated that over 90% of the brain weight is indeed reached by age 5 and a lot of brain development does happen by then. But a bulk of that involves simply learning to walk and talk.
Besides brain development is not merely about brain weight, or fat head would not be an insult, now would it ;) There is another crucial component to brain development, and that is the connectivity between various sections and regions of the brain.
Network, Network, Network!
It’s not about how big you are, but how well connected you are. This is definitely true about your brain.
Better connectivity is associated with improved learning abilities. The connectivity between the different regions of the brain rapidly grows during the teenage years. So, no, life is not over at 5 as some preschools would like to have you believe.
In fact, the side effects of the rapid growth in brain connectivity and intense brain development in the teenage years manifest through a number of classic teenage traits, like lack of self-control, heightened tendency towards risky behavior, lack of foresight etc.
It’s the growing brains that cause the growing pains.
Far from being fully developed, merely with less mileage than an adult brain, during the early teenage years, the bulk of the wiring in the brain is in its infancy. According to this time magazine article, the teenage brain has a lot of plasticity so it can adapt and respond to its environment. Even mental abilities are not set in stone, and between the ages of 12 and 20, IQ can either improve or deteriorate.
According to this paper, a surge of synaptogenesis occurs during adolescence and it is one of the most dynamic periods of brain development, second only to infancy. During this period white matter, which acts like insulation upon neural wiring and improves the speed and efficiency of signal conduction in the brain, significantly increases, thus improving the ability to learn.
Sex hormones during puberty are responsible for activating and connecting various sections of the brain.
The Imbalanced Teenage Brain
Teenage behavior is often blamed upon an underdeveloped prefontal cortex. But that’s not the whole picture. For example, a child’s prefontal cortex is less mature than that of a teenagers. So, why is the prefontal cortex blamed for the unique teenage problems?
There is a flurry of activity going on in the teenage brain with growing connectivity. But this wiring process begins at the back of the brain and works its way forward reaching the prefontal cortex last of all. So the teenage brain is imbalanced, with parts of it far more connected and developed than others. The prefontal cortex in the teenage brain is relatively less connected than other parts of the brain, especially the emotional and motivational sub-cortical sections. It is this imbalance that manifests itself in classic teenage behavioral patterns of lack of self control and susceptibility to peer pressure.
As an effect of the advanced wiring of the back of the brain as compared to the front, teens tend to be unusually susceptible to peer pressure. The interesting thing is that studies show that peer pressure can be very subtle.
For example teen decisions on risk taking are influenced simply by them believing they are being watched by peers, even if those peers are strangers! Teens are also unusually sensitive to positive social and emotional cues from their peers, and their behavior, sometimes even without realizing it, is strongly modified in the presence of peers.
Risk taking behavior in teens is comparable to that in adults when they are alone, however teens show significantly higher propensity towards risky behavior in the presence of peers.
Among adolescents the reward seeking part of the the brain in highly sensitive causing them to crave rewards and seek novelties and thrills. This makes them susceptible to nicotine, alcohol and drug addictions. Add to this, dopamine (the neurotransmitter for pleasure) levels fall during adolescent years. So adolescents need to have higher levels of stimulation to achieve the same levels of pleasure, which drives them to take greater risks.
Adolescents are more likely to develop alcohol use disorder than adults even at lesser exposure to alcohol. Although the exact effects of drugs on brain development are not known, there is mounting evidence that drug use has adverse effects on learning.
But it is important to remember that risk taking is a normal part of adolescence as it helps in self discovery, discovery of the world at large and to develop new skills. However increased propensity for risky behavior makes adolescents 200% more likely than children, to put themselves in harms way.
Adolescence in an exciting and turbulent time when the body and brain gear up for independence and struggle to establish an identity. Novelty and thrill seeking risky behavior help teens experiment, learn, and acquire new skills, but also results in an increase in danger of injury, harm, substance abuse disorder and death.
In their quest for independence adolescents are on a journey of self discovery and looking to find their place in society and the world at large. Increased sensitivity to emotional and social cues from peers can help them with these goals ,but peer pressure also pushes them towards more risky behavior.
This time of transition is fraught with emotional land-mines, but the body being in its prime and heightened reward sensitivity also lends a feeling on invulnerability. One has to take the good with the bad, but it may help teens and those responsible for them to understand why teens behave the way they do, to help them address the many problems of adolescence as effectively as possible.
Growing Pains is a young adult novella about school, friends, siblings, family, illness and a first crush.