“She’s a teenager, what do you expect?” That was how my mom used to explain my rowdy behavior. Why do adults say things like that? Is there something wrong with teenagers? What’s going on in the teen brain? As you move from childhood to adulthood, your brain changes in a way that makes it possible for you to strike out on your own. But be careful! The same changes tend to make you impulsive and reckless.
Studying the brain
Did you know? Some of the myelinated axons in your brain can transmit information at 400 kilometres per hour. That is faster than a race car.
Until recently, the human brain was hard to study. To look inside someone’s skull, you had to use high-energy radiation like X-rays. But these rays can give people cancer, so doctors only used them only when absolutely necessary. And researchers couldn’t risk making people sick just to look inside their heads.
But things changed about in the 1990s with the arrival of Magnetic Resonance Imaging (MRI). MRI machines can take detailed pictures of the brain without the need for X-rays. So they’re safe to use, even on children. They can even be used to see how different parts of the brain develop and communicate with each other over time. As a result, brain research is expanding fast. And scientists are getting a much better idea of what’s going on in the teen brain.
Between puberty and adulthood, people change dramatically. During this time, children become capable of living independently of their parents. It’s when you mature and develop your own identity. This is crucial to the survival of the human species. If you and your peers never became adults capable of building your own lives and families, humans would die out pretty quickly. But growing up is a difficult process. Is the human brain designed to overcome these difficulties? Maybe it is...
The teenage brain explained (2014)
The human brain is made up of many interconnected parts. Each of them has its own function. Different things you do—such as seeing, moving, smelling, loving, or thinking—are run by different parts of the brain. And these different parts need to talk to each other to coordinate their actions.
However, during childhood, there is less focus on communication between different parts of the brain. The important thing is to get each part working properly. But at puberty the focus shifts. For you to independently explore the unfamiliar and learn how to stand on your own feet, your brain needs to improve its communication system.
What changes in the teen brain to give it an increased capacity for networking? Scientists think it’s the accumulation of a white, fatty substance called myelin. Brain cells whose wiry extensions (axons) are wrapped in myelin communicate information faster and more frequently. They are also better at coordinating with other brain cells. Myelinated cells form the brain’s white matter, which expands in the teen years. This could explain why teens are so good at adapting and learning.
Losing grey matter
However, the unmyelinated portion of the teen brain—the grey matter—actually shrinks. This is surprising, since grey matter contains synapses. These are the structures that your brain cells use to connect with each other. So how could cutting down on the number of synapses help your brain mature?
Rather than getting rid of important material, it seems the teen brain is simply cleaning house. During childhood, your brain forms synapses easily. It builds up a lot of them as the amount of grey matter grows. But the teen brain must become more effective and specialized. To accomplish this, it gets rid of unused or broken synapses and strengthens the ones it uses frequently. The net result is fewer but better connections—and a more mature brain.
Did you know? The prefrontal cortex is the last part of your brain to mature. It only fully develops around age 25.
But there’s a catch: the different parts of your brain don’t all get upgraded at the same time. This helps explain why teens are so often impulsive and reckless. The area in charge of emotions (the limbic system) matures early. The one that regulates behavior and the ability to make decisions (prefrontal cortex) matures late. As a result, teens are capable of deep and complex emotions over which they may have little control.
Is there a purpose to this? Let’s assume teens’ capacity to judge risks and consequences was fully developed. Would it be as easy to get them to leave the security of their parents’ homes and explore new territories? Probably not. This may be why emotions override judgment in the teen brain. It pushes you out of your comfort zone and into the unknown while your brain is still highly adaptable and has lots of room to improve.
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Is the teen brain up to no good? Far from it! In fact, it is up to great things. The potential for learning and creativity is at its peak. But so is the risk of physical injury and mental illness. Still, it’s empowering to understand what’s going on up there, isn’t it?
Articles and websites discussing how the brain develops during adolescence:
Articles and websites with general information on the human brain and nervous system: