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Teens

The Teenage Brain

Published: 11 Jul 2022
Teenbrain

Today it is common knowledge that teenage brains are neurologically immature. Essentially everyone recognises and accepts that the teen brain is “under construction”, “lacks brakes”, or is "controlled by emotions". Almost anyone can - and likely will - tell you that teens are so emotional and unpredictable - and crazy - because the emotional part of the brain (limbic system) is fully online, but the thinking part of their brain (prefrontal cortex) is still being developed. 

But this is not entirely true, and not particularly helpful. 

That is… it might be common knowledge, but these ideas need some modest modifications. I’ll share, in this article, what’s actually going on in your teenager’s brain, specifically as it relates to:

  • their challenging behaviours around risk, and
  • their lack of concern for anyone but themselves. 

Then I’ll explain what this actually means for us as we raise our teens.

Everything happens so much

One of the most famous Twitter memes of all time comes from the @Horse_ebooks account, and states that “everything happens so much”. 

Everythign happens so much twitter

No truer statement, however bad the grammar, could apply to the teen years. This period brings specific and important developments, socially, psychologically, cognitively, academically, romantically, physically, emotionally, neurologically. 

A lot happens. All at once. SO. MUCH.

One key area is the impact that peers have on adolescent behaviour. Compared with adults, teenagers who are around their friends (or who simply have an audience) are more likely to:

They think they’re the centre of the world and that everyone is watching them! Adults are relatively unimpacted by having peers around them in each of these conditions, but teens… wow.

What does this mean - in practical terms - for us, as parents?

It means that teens can be completely sensible and adult-like when they’re on their own or with adults. But when they’re with friends and peers, their filter is removed. In these circumstances, many teens follow the crowd, push for popularity by doing outlandish (and often unsafe) things, and fail to consider how others might feel about their actions. 

At the same time as these psychosocial changes, there are tremendous biological shifts in the form of hormonal and physical changes that characterise puberty. Plus there’s the ongoing and substantial development of the brain. 

In the days before brain scans…

The idea that the adolescent brain is under development is a relatively new concept. It’s only been in the last three decades that we’ve understood the degree to which the brain continues to develop beyond childhood. In fact, even the concept of teens is kind of a new thing. 

The term, adolescence, didn’t exist until a man who later became head of the American Psychological Association wrote about it in 1904. G. Stanley Hall claimed that this phase he called “adolescence” could be identified due to three central elements: 

  • mood disruptions, 
  • conflict with parents, and 
  • risky behaviour. 

Hall argued that this developmental period of adolescence was a time of “storm and stress” and that society needed to “burn out the vestiges of evil in their nature”. I guess it’s fair to say Hall didn’t like what he saw in emerging adults.


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So we started talking about adolescents in the early 1900s. But this age group was recognised as trying as far back as Shakespeare (at least). Romeo and Juliet was a tale of two kids who risked it all and died tragically because of their impetuous nature as teens! And the Old Shepherd in Shakespeare’s The Winter’s Tale, lamented:

I would there were no age between ten and three-and-twenty, or that youth would sleep out the rest; for there is nothing in the between but getting wenches with child, wronging the ancientry, stealing, fighting—Hark you now! Would any but these boiled-brains of nineteen and two-and-twenty hunt this weather?

The issues of misguided priorities and faulty decision-making has been a hallmark of the teen meme for centuries! 

But teens really came into their own during the 1950s and onward. (They were initially called teeners but that didn’t stick.) During the 50s, participation in high school until Grade 10 became the expected norm. Large groups of teens hung out together, and, according to a writer in the New Yorker in 1958, marketers began to see them as a specific audience with disposable income to be exploited by businesses. Building on classical concepts from Shakespeare and psychological ideas like those of Hall, the Rebel without a Cause concept caught on, and created an archetype of rebellious and rambunctious teen culture that has remained resilient over the past 70 years.

How the brain develops

As brain imaging techniques have advanced, theories have emerged to explain why teens can be so difficult. Studies show that this is what happens as our children’s brains develop (and this is seen across cultures): 

  1. During childhood we see grey matter (commonly termed brain cells or neurons) increase enormously fast. 
  2. This makes the cortex become thicker and more voluminous up until the early teen years. 
  3. But as the teen years progress, the number of brain cells and neuronal connections decline (and cortical thickness and volume diminish) at a vanishingly fast rate, eventually levelling off as our children arrive in their mid-20s. 
  4. While this reduction of grey matter (brain cells) occurs, the development of cerebral white matter (myelin) increases through a process known as myelination.

Let’s go deeper on this for a moment:

From childhood, the brain has way more neurons and way more connections (synapses) between those neurons than it needs. They develop because the brain collects information through experience and holds onto all that it can. As the brain matures, it has to prune excess cells and synapses to make the brain circuitry more efficient. Loads of those cells and synapses made during childhood aren’t being used, but they’re taking up space. They’re slowing things down. They need, therefore, to be pruned.

Think of it like your broadband connection. It works great until everyone is using the WiFi. Once you’ve got five phones, three laptops, and two TVs all downloading content, it can’t keep up. Too many connections! So in the same way that you start shutting a few of those devices down to keep the signal going where you need it most, the brain starts pruning cells and connections to improve connectivity and efficiency. It keeps what gets used a lot. It gets rid of connections that aren’t deemed as important.

As the grey matter (neurons) disintegrates and deletes itself, the white matter (myelin) begins to develop. Myelin acts as an insulator. Essentially the myelin wraps itself around the grey matter to make the process of sending and receiving signals more efficient. This myelin works the same way that the rubber or plastic wrapped around an electrical wire works. It directs the signal from A to B without it diffusing into the environment. And it speeds the signal up! 


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One further point: it is widely recognised that girls’ neurological development is, on average, around two years ahead of boys’ neurological development by the end of the teen years. Boys catch up by around age 25. (This explains, at least in part, why girls seem more mature than boys - although there are many other factors at play here too.) As an example of why this matters, this study on cognitive control highlights female maturity as an advantage over male immaturity. 

 A variety of other factors impact how the brain develops but they’re a little outside of the scope of where this article is headed.* 

Why does this matter?

Think about what happens when the road network in your area is being upgraded and redeveloped. It usually means delays. It requires you to go slowly and work through the gridlock with patience and understanding, knowing that in time, the works will be completed and traffic will flow better than ever.

Right now, your teen’s brain is like that road network. And it’s going to take a few years of upgrades before they’re where you want them to be. The important thing to remember is that we can help these developing brains by keeping things level and balanced. Be willing to patiently go slow. It’s this willingness that allows your child the space she or he needs to figure things out, work through challenges, and keep developing healthily.

Risk-taking in adolescence

The common narrative that we consistently hear is that adolescent decision making is compromised because of the differential between limbic system development (where emotions are) and prefrontal cortex development (where thinking occurs). It’s this developmental discrepancy that explains unsafe, unhealthy, and unwise choices in adolescence. (The figure below shows this neurodevelopmental gap, which purportedly results in increased risk-taking behaviour in adolescence.)

But this isn’t exactly accurate for a number of reasons. What we know is this: 

Risk taking increases with the onset of puberty due to increased reward seeking behaviour. This is exacerbated by social factors. Kids want to be seen a certain way by their peers and so they seek the reward that comes from appearing brave or strong, or perhaps just a bit wild. During this time, the brain is remodelling its reward connectivity (dopaminergic system) within the socioemotional system (limbic and paralimbic areas of the brain) and these unsafe, unhealthy decisions suddenly seem like a smart idea.

However…

While risk taking isn't confined to the teenage years, the inclination for risk-taking behaviour actually peaks in late adolescence. That is, kids start doing “dumb” stuff young, but their desire to do risky things peaks in the later teen years. And peak risk-taking behaviour occurs in early adulthood! They start really acting on those desires around age 19-21. 

But if we look at the age where our young people are experiencing the most misalignment in neural development, it is around the age of 13-15 years. In the figure above, that’s the time where the gap between prefrontal cortex development and limbic system development is greatest. So theoretically we should be seeing more risk-taking inclination and behaviour in those early teen years than at any other age.

Instead, kids in their early teen years aren’t generally engaging in risky behaviours nearly to the same extent that kids in their late teens or early twenties are. 

Risky behaviour and gender

Similarly, while males show greater real-world risk taking behaviours, there is no significant difference in risk-taking propensity between genders. That is, girls are just as likely to have the desire to engage in risky behaviour, but they don’t follow through like boys do. For reference, these were the risks looked at in the study linked in this paragraph:

Health-related risks: drinking alcohol, getting in the car with a drunk driver, smoking cigarettes, and having unprotected sex

Antisocial risks: vandalising, stealing, fighting, walking through a dangerous neighbourhood, and threatening someone.

This disparity is most likely due to the difference in opportunity between males and females to engage in real-world risk taking behaviour. Guys simply have more chances (and take more chances) than girls.

In the same way that gender expectations are associated with real-world risk taking, we can argue that curiosity and a desire for experience combine with opportunity in later teen years to create risky behaviours. After all, 13 year olds can’t engage in risky driving, alcohol abuse, or cigarette use and vaping (at least not legally) in the same way that an 18 year old can.

Moreover, some research suggests that challenging teen behaviour is a result of self-fulfilling prophecy. Studies have shown that teens who agreed with more negative statements about the developing adolescent brain showed increased risk-taking behaviour when compared with teens who didn’t agree with those statements. 


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There are tremendous individual differences when it comes to unsafe, unhealthy behaviour by teens. Even kids in your local community show enormous differences in the degree to which they push boundaries and engage in unsafe, unhealthy behaviours. If it were really their brain development, all kids would be doing the same unsafe, unhealthy things. But they’re not. In fact, many don’t.

Risky adolescent behaviour, it seems, is less about brain development and more about the combination of curiosity, peer influence, status seeking, opportunity, and self-fulfilling prophecy that leads our kids up the proverbial garden path when it comes to their challenging behaviours.

Empathy in adolescence

Cognitive empathy, or the mental ability to take others' perspectives, begins rising steadily in girls at age 13, according to a six-year study published in Developmental Psychology. This capacity is processed in the prefrontal cortex; the executive of the brain that is relatively underdeveloped (meaning too many brain cells and not enough myelin) during adolescence. Curiously, we don’t see similar gains in perspective-taking (cognitive empathy) in boys until age 15. 

Not only do our teen boys lack cognitive empathy, but that same research found that from ages 13 through 16 boys’ affective empathy drops; which is the ability to recognise and respond to others' feelings. It does recover in later adolescence. But for girls, it’s always there: stable and high. 

Let’s restate this clearly: 

  • Boys don’t experience cognitive empathy gains (ability to take another person’s perspective on emotional things) until around age 15. 
  • And boys experience a reduction in affective empathy (feeling what someone else feels) from age 13 through 16.

Meanwhile:

  • Girls experience a steady rise in cognitive empathy from age 13.
  • And girls experience stable, high levels of affective empathy throughout their adolescent years.

The brain is implicated in empathy development. But the evidence suggests that there are no specific differences in patterns of neural activity between the sexes for empathy, even though females score higher on pretty much all measures of empathy. 

This tells us that empathy is less about brain development and more about social conditioning. We accept girls displaying emotions across the spectrum. Boys, not so much. (And even if “we” do, many in society do not.)

The summary

We make a really big deal - consistently - about how we need to better understand the brain so we can better understand ourselves and our teens. While it’s fascinating to learn and discover how our brains work, my view on this is different:

While advancements in the field of neuroscience are helping us develop targeted treatments for depression and even helping paraplegics walk again, you don't need a PhD in neuroscience to be a good parent. In fact, as we saw earlier, having an incomplete or overly simplified view of brain development can even make parenting harder. Ultimately, whether something is happening in our children’s brains or not, we still need to work out how to navigate what life sends our way. Brain research can inform parenting practice in general, but it doesn't tell us what to do or how to do it in the moment.

At this point, what we do know is this: 

  1. The teen brain remains neurologically immature because it is still developing in important ways. 
  2. Issues with emotional and behavioural regulation tend to improve with age.
  3. Sensation-seeking and risk-taking behaviours that put our children in unsafe, unhealthy situations tend to be more about socialisation practices, expectations we place (or don’t place) on kids, their natural curiosity, and other personality characteristics than neurodevelopment per se.
  4. Empathy development, while it has a neurological foundation, is likely to be more related to how we socialise boys versus girls, and appears to be more culturally determined than neurologically based.

All of this brings us to the final question:

What can we do as parents?

I could write entire books about the smartest ways forward for parents of teens. (Well, I have written one!) Instead, I’ll share just three ideas to guide your interaction with your teen when it comes to brain development, and then three ideas to guide your relationship with your teen when times are tough, regardless of whether adolescent brain development is implicated in these things or not.

1. Remember that there are positive and negative dimensions of risk taking behaviour, with impulsivity separating the two. And very little of this has to do with the brain. Most of it is related to your child’s desire to experience life and all it has to offer. The real question is whether they’ll be enticed by their peers’ less safe, less healthy choices, or by alternative options.

It is possible to satiate teenage curiosity and desire for excitement in safe ways. Healthy risk taking is 

  • Socially acceptable
  • A necessary part of adolescence 
  • Something that allows teens to explore and develop their own identities, and 
  • Something that gives teens practice making their own decisions. 

By practising taking healthy risks, teens have an opportunity to develop their cognitive control system, narrowing the developmental gap between reward seeking and self-regulation. Our job is to talk with our teens about controlling their risks, and ensuring that they’re healthy risks, and safe, wise risks. This is where supporting their autonomy becomes vital.


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2. "Boys will be boys” is no excuse for poor behaviour. Don’t be so quick to excuse gender differences as being due to brain differences. While this plays a very small part, it can also give boys in particular an excuse for suboptimal behaviour, or weaponised incompetence. Our boys can do better and should be held to a higher standard without the fallback to “my brain is just too immature.”

3. Instead of focusing on ‘deficits’ of the adolescent brain (which can excuse suboptimal behaviour), focus on the benefits (greater flexibility and plasticity allowing for greater learning possibilities). Teens have more brain cells than adults, they are better able to build synapses between neurons, and this means that they are able to learn easier and quicker. Let them know this, and point your expectations towards development and growth rather than foolishness, risk, and disrespect.

And to maintain and strengthen those bonds, try these three reminders:

  1. Emphasise connection over correction and direction. Make sure they feel seen, heard, and valued. This is vital. Your teen should know that you have high expectations, but that you love them. Say it. Regularly. And remember the three critically important words that come next: No. Matter. What .
     
  2. Practice supporting your teens’ autonomy. This means that when there is a decision to be made, pause and invite them to explain what they’re thinking. Explore why this is their approach. And empower them to choose wisely, safely, and healthily.
     
  3. If your teen confesses to doing (or seeking to do) something unsafe, unhealthy, and unwise, avoid shame. Stay away from power trips. And dissuade yourself from self-recriminations. Show compassion for your teen and invite discussion: “I would like to know more about your thoughts. And I would like to share some things that persuade me that there may be alternative choices that would be more helpful.” A continuing discussion where we are curious, not furious, can make a difference.

Raising teens can be tough. But the good news is that the vast majority of them make it through their adolescent years without any major mishaps, health issues, or trauma. This doesn’t mean we won’t experience stress and strain, and plenty of mild anxiety attacks. But it should give us hope. Regardless of what is happening in their brains, we know that the basics work when it comes to our relationships with our teens, starting with connection. 
 


*Other factors that impact brain development

The amount of sleep, the way the media is used, the quality of diet, the experience of friendship vs bullying and ostracism… so many factors play into how the brain develops. 

Money and education matter too. For example, in one cross-sectional study of 1099 participants aged between three and 20 years, number of years of parental education was associated with larger cortical surface area in many brain regions involved in language, reading, social cognition, executive functions and spatial skills. In short, better educated parents seem to have kids whose brains develop more than parents with less education. (Other studies show similar results.) It seems that socioeconomic factors have a meaningful influence on how the brain develops and reacts to difficulty.

And different cultures have different expectations of how a teen should behave… and they’re right! Teens from cultures where family obligations were stronger and becoming independent at a young age was expected showed different (and better) brain responses when their brains were monitored during risk-taking and prize-winning activities.
 

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