‘Being a teenager … is incredibly intense and every moment is invested with ferocious importance.’ Ol Parker

For literally centuries, the older generations have despaired of the behaviour of teenagers. They seem to forget that they were teenagers once too! Since being discovered by scientists over 100 years ago, for decades sex hormones have been blamed for the seemingly wild and confounding behaviours observed in teenagers. While hormones and the onset of puberty do play a big part, massive leaps in neuroscience over the past 30-odd years show us that there's a lot more going on and it’s happening in the brain.

Advances in brain imaging technology mean that scientists are continuing to learn more and more about how the living brain changes in structure and function across the human lifespan. Being able to actually look inside the living human brain and track what is happening has been truly enlightening: it turns out that it is effectively being remodelled throughout the period from around 12 to 25 years of age!

In this blog, we’re going to discuss some of these neuroscientific understandings about how the teenage brain works, covering the following areas:

the science of brain development
why teenagers’ emotions feel so intense
the social brain - the importance of peer approval
risk-taking behaviour

In our next blog, we’ll continue this topic, looking at how the developing teenage brain is affected in relation to sleep, attention, focus, learning and studying. We’ll also look at how we might harness this understanding of brain science to actually help optimise our growth and development.

So, what is going on inside the amazing teenage brain?

Brain science

The human brain is incredible! This first section contains some scientific facts about the brain that will help you understand what’s going on in the teenage years.

Your brain contains between around 85 and 100 billion nerve cells - neurons - which send super-fast messages to each other, allowing all sorts of things to happen including thoughts, actions, memories and decisions. It’s like an amazingly complicated web of branches. Each neuron has a long ‘tail’ called an axon. From the centre of the neuron (nucleus) sprout many branches, which are known as dendrites. Communication between the neurons happens by electrical currents being sent along the axon of one neuron and across miniscule gaps - known as synapses - into the dendrites of other neurons. Literally every single thing your body does throughout your life is because of these neurons firing off the right messages through this complex web.

Babies are born with neurons, but as there are so few dendrites and synapses, they can’t do much at first! Their brains develop so fast though, that within the first few months and years of life, thousands of these connections are made. These allow each child to learn how to move, speak and think. The more you repeat the same thing - action, thought, recall - the stronger and more established that particular connection within the brain becomes. If you don’t use a connection very much, then it can die off. That’s how you can forget to do something if you don’t do it for a long time. To learn or re-learn anything, you have to practice - practising means that the specific connection in your brain gets stronger again. It’s like watering and feeding a tree to help it grow.

Mirror neurons are neurons within our brain that fire up when we watch someone else doing something. For example, if you watch your woodwork teacher use a saw a few times, before trying it yourself, it might be easier for you than if you hadn’t watched first. It’s like your mirror neurons have already practised it inside your brain - your brain is that fast! This helps to explain how we learn all sorts of things by imitation.

The part of the brain that sits highest within your skull, is called the cortex - this is the part that thinks, reflects, perceives, remembers, plans, makes decisions, weighs up options, and many other important executive functions. The front part of this - known as the prefrontal cortex - develops very quickly during babyhood and childhood, and even more dramatic changes take place there during adolescence.

The limbic system is the area of your brain that controls emotional and unconscious or reflex behaviour. Sometimes it’s referred to as the ‘reptilian’ brain or the ‘chimp’ brain. It is driven by feelings and instincts. It is the oldest part of the brain, and is, for example, what fuels babies’ behaviour to cry before they start developing neural connections and learn how to say what they need. The amygdala is a tiny part of the limbic system, but it plays a big role in processing emotions, particularly the fear and the stress response.

Teen Brain Development

Around the onset of puberty, there is a significant increase of grey matter in the prefrontal cortex. This means that there is sudden sprouting of even more neural connections at around the ages of 10-12 years in the darker essential tissue of your brain. There are then too many of them, and they need to be cut back, or ‘pruned’ - which is what happens inside the brain over the next few years.

During the pruning years - early adolescence - a significant amount of grey matter is lost from the brain. It’s almost as if the brain is deciding which connections are worth keeping hold of and which ones to let go of - there isn’t room for them all. Then, in late adolescence and early adulthood, the connections or branches that remain are strengthened and built up through a process called myelination. The brain coats the membranes of the interconnected neurons with myelin, which is a sheath that enables the faster and more coordinated flow of information. In this way, the brain is effectively ‘remodelled’, so that it can work in more efficient, effective and complex ways once you become an adult. Dan Siegel writes that the brain’s aim of adolescence is integration: after being remodelled, all of the different parts of the brain can communicate with each other in a fluid, balanced way, which supports all the vital brain functions of planning, reflection, empathy, decision-making, and awareness of self and of others.

During this time of tremendous upheaval within the developing brain, there are lots of things that may be more challenging about living life for adolescents than for adults. You may be beginning to look like an adult on the outside, but the inside of the brain is still very much under construction! Let’s dive in and look at some of the parts of life that are affected by these brain developments.

Emotions: intensity and drama

When your prefrontal cortex is in the vulnerable state of being pruned, it works less effectively for you in some situations. This means that it can be harder to access the executive brain functions of reasoning, planning, logic and accurate perception, among others. You might find yourself suddenly becoming angry or emotional in circumstances that wouldn’t have affected you like that when you were a little younger.

At the same time, your emotional lower brain - the limbic system including the amygdala - is more activated during adolescence. As you’ve also temporarily lost some of the calming effects of the prefrontal cortex during this remodelling phase, it’s no wonder that emotions are felt so rapidly and intensely! This will be especially so when you are tired, not eating well, and feeling the pressures of teenage life. Those pressures may include:

Friendships and fall-outs
Pressure at school
Exams
Part-time jobs
Caring responsibilities
Fears for the future

You’ve probably noticed that stress makes all humans more prone to being snappy, grumpy and moody, and this is even more pronounced in the teenage brain.

From an adult’s perspective, it can appear a bit like the teenager is reverting to their earlier toddler/preschool behaviour. The teenager’s outbursts and subsequent door-slamming or similar can feel a lot like those earlier tantrums! It can help adults to understand what’s going on inside your brain, so that they can try to support you just like they did when you were little.

Another factor that can affect emotions is that studies have shown that teens - and particularly younger teens - are generally less able to interpret facial expressions as accurately as older teens and adults can. The good news about this is that the ability to read facial expressions generally does improve as you get older! But while it’s trickier for you, this is because your amygdala is being activated - the part that feels gut reaction and raw emotion, and doesn’t actually ‘think’ at all. Here are a couple of examples of situations and facial expressions that you might decipher inaccurately:

Another kid at school gives you a blank expression or bumps into you in the school hallway. You may feel that they are being intentionally rude or aggressive, but it could actually be neutral or an innocent mistake, and not about you at all.
Mum comes into your room to ask you how you’re getting on with maths revision for your test this week. She asks if she can help, and you erupt in anger and tell her to get out of your room, that you’re doing it yourself. You’ve interpreted her questions and offers as coming from anger and distrust in you; from her perspective, she’s worried and concerned about how you are getting on with your studies and offers to help because she loves you and wants to support you.

All of this may explain why friendship dramas and bullying, and of course other life events that can happen within families during teenage years, such as parents’ separation, death of a pet or family member, illness etc can feel that much more intense than they may do for an adult. Of course, all humans of whatever age are upset by these things happening. But when your brain is literally still under construction, it’s felt that much more deeply and painfully, and without the fully developed cortical functions to help you make sense of your feelings. So, it’s entirely normal to feel deeply and fiercely at this stage of life.

Throughout adolescence, you are experiencing things for the first time consciously, making important memories as your brain is being re-wired for adulthood. Everything is more intense the first time it happens to you - fall-outs, crushes, exams, interviews, relationships and so on. At the same time, you are undertaking the vital task of growing up that has been experienced by humans for millennia - separating from your parent/carer protection and becoming more self-aware. These two factors are also relevant to our next two topics.

‘When you are in your teenage years you are consciously experiencing everything for the first time, so adolescent stories are all beginnings. There are never any endings.’ - Aidan Chambers

The social brain: peer approval matters!

As you begin the task of growing up and separating from your family, your friends and social life can feel more important than anything else. Peer approval - having people like you and want to hang out with you - really does matter to the teenage brain. Often it can feel like it matters much more than whether you please your parents. Getting that respect from friends and potential friends is compulsive. You have a very strong human desire to fit in with those around you because from a human evolutionary perspective, being part of the group is the safest place to be. These days we are not usually in a group to actually protect ourselves from wild predators, but our brains still operate in a similar way even though our environments are so different. Our biology drives us to make these social connections for support, collaboration, relationships and fun. Intense social engagement is a fundamental part of adolescence.

Neuroscientists have also discovered that teenagers are more sensitive to social embarrassment and peer opinions than other age groups. The feeling of caring so much about what other people think can also be felt very intensely, but this does tend to diminish as we get older and have more life experiences.

Some teenagers may also notice an internal conflict between wanting to fit in and not be noticed, yet somehow at the same time stand out as special and be a bit different. This internal tussle may be experienced alone or with a tight group of friends, and may be why friendship group styles develop - everyone is trying to find a place to fit in, whether it’s mainstream or counter-culture, so they seek like-minded folks to be with.

You may have noticed that you are spending more time with friends than you used to, and more time communicating with them. In the olden days of the 1990s - pre-mobile phones! - this looked like spending all day together at school, walking home together and then spending hours chatting on the landline phone later on in the evening. Parents would wonder what on earth there was to talk about for that long! Nowadays some of the in-person chatting has been replaced by messaging on social media and messaging apps. The fear of missing out (FOMO) coupled with the teenage brain’s less effective prefrontal cortex means it’s almost impossible not to keep checking your phone to see what’s happening! Adults often say that teenagers are addicted to their phones, and there is brain science that backs this up. Social media especially taps directly into the reward drive in the adolescent brain, which is increased compared to that of other age groups.

During the teenage years, there is a surge in the activity of the neural connections using dopamine, which is the neurotransmitter that creates your desire for reward. This means that teen brains are actively searching for stimulation and novelty - something which social media can provide in abundance. This increased drive for reward can also affect other areas, as we’ll see below.

‘The inability to resist risky behaviours, coupled with the heightened sensitivity to stress, results in impulsive actions with immediate reward - an inherent teenage pathology.’ - Kenneth S. Rosen

Risky behaviour

The operation of dopamine within the brain explains why teens alternately feel elated or bored depending on what they are doing - again, more extreme, intense feelings than other age groups typically experience. Neuroscientists have found that dopamine in the teen brain starts at a lower baseline than for adults, and then is released to a higher level than for adults when they engage in new, exciting things. Teens can feel so powerfully alive when this happens, that they want to seek out the feeling again. This, combined with their prefrontal cortices being less effective at weighing up risks and dangers, is why teens are more likely to try new things - the positive reward is the draw, and the potential risks may be barely considered, if at all.

Risk-taking in general isn’t negative: lots of good things happen in life as a result of taking a risk. Asking someone out on a date, trying a new sport or hobby, applying for a job or course of study, travelling - these are all examples of where taking a risk could enhance the quality of your life. However, these kinds of risks are usually made following some kind of weighing up of pros and cons, benefits and downsides of each option. In contrast, during the teenage period when the brain is under construction, you are also much more likely to make impulsive decisions. This is acting without any kind of pause. Depending on the situation, this could be very fun and/or extremely dangerous! And when the social brain meets the reward driven brain, anything can happen. You may do certain things within a social group that you would never think of doing while alone - for example, jumping off a cliff into the sea without any safety measures, or taking an illegal drug at a party.

Although there are negative associations with reward-driven risk-taking behaviour, such as an increased vulnerability to developing addictions and an inability to consider the bigger picture, there can certainly be positive sides to it too. It can be really great to step out into the world and try new things: think of all the great art, music and technological advances in our world that originated from teens trying something new! The pushing away of ‘old ways’ and the seeking out of new solutions leads to incredible creativity and innovation.

In our next blog, we’ll look at ways to harness these amazing teen brains, and build good habits that optimise growth, development and brain integration.

‘When I was a teenager I felt like we were always being stereotyped as being really intense and dramatic and passionate and hopelessly romantic and excitable, now in retrospect I think I need to let you know those things are amazing. I hope you never lose those things.’ - Taylor Swift

Asking for help

If you are feeling different than you used to now that you are a teenager and getting older, and it’s hard to understand why you are feeling and behaving the way you are, do consider talking about this with a trusted adult. A parent, guardian, older sibling, friend, relative or teacher may be able to listen and provide valuable support - after all, they were all teenagers once too, even if that was a long time ago and seems hard to believe! Try to choose someone who you know is a good listener.

Some things you might like to discuss:

what are the particular problems you are having with being a teenager?
whether you need some support with some specific aspects of your life
what does the trusted adult recall about how it felt to be your age?
whether the adult has any useful advice or guidance to give you

If you are struggling to identify someone in your personal life to have this discussion with, get in touch with us!

Our challenge to you

This week, try to notice how you are doing in relation to the three main topics we have covered in this blog: emotions, social connections and risk-taking. Maybe use a notebook to jot down some observations. Some aspects to consider include:

What emotions have you felt very intensely this week? Did other people treat you as if you were over-reacting? Have you ‘flipped your lid’ this week? Or do you keep your emotions to yourself?
Do you have a fear of missing out? If so, what kinds of behaviours does that fear lead to, both online and in real life? Do you feel accepted by your peers? What aspects of being a teenager and spending lots of time with friends do you most enjoy and why?
Have you made any impulsive or reckless decisions this week? What things have you done as a teenager that you would not have considered doing when you were younger? Did doing these things - or does the idea of doing them - feel exciting, scary or perhaps a combination of both?

‘*It takes courage to grow up and become who you really are*.’ - E.E. Cummings

Further resources