That, or something close to that, is what a teenager said to me about her peers. She was the narrator in a young-adult fiction book I was reading the other day (no, not Twilight). I was instantly pulled out of the narrative of the book, and found myself ruminating on the fact that those sentences would never have been included in any book – young-adult fiction or other – a little more than a decade ago.

When scientific findings or philosophical theories trickle down to matter-of-fact inclusion in young-adult fiction, it’s clear they’ve reached critical mass. Those findings or theories, and all the possible implications have, rightly or wrongly, become a given. They have become unquestioned reality.

I have a problem with the assumption that’s quickly become accepted ‘truth’ about teenage brains: that they are underdeveloped in a couple of critical areas, and that teenagers are, therefore, biologically inferior and less-than-capable. But my road to this conceptual push-back took several years. So it might be helpful to step back a few years and fill you in on the nexus and my journey of trying to understand scientific findings about teenage brain development, and the implications for youth ministry. 

“I wanted to tell them that they’re not capable of making good decisions, because that part of their brain isn’t developed yet. That, I guess, is the whole irony of being a teenager: you need to make good decisions, but you can’t.” 



For hundreds, maybe thousands of years, the human brain was assumed – by the entire medical community and all of its off-shoots – to be fully developed by early childhood. Sure, it would continue to grow in overall size, and it needed tons of additional data inputs and experience. But that was understood as a qualitative change, not a quantitative change – a tweaking and maturation, not a substantive leap. 

Brain Fact #1: Your brain keeps developing until your late 40s. 

You’ve probably heard of a Swiss dude named Jean Piaget. In the middle of the 20th Century, Piaget developed his theory of cognitive development. Based on years of research in the new field of developmental psychology, Piaget suggested that the human brain goes through a handful of marked stages in how it processes and understands information. Or, one might say, the stages provide different means of knowing things.

For youth workers, the important stage to understand is the last one – the move from concrete to abstract thinking (or, as Piaget put it: from ‘concrete operational thinking’ to ‘formal operational thinking’).

This shift from concrete, black-and-white thinking to the ability (if not always the practice) of thinking abstractly, completely re-wires the worldview of teenagers. They are, for the first time, able to perceive themselves from a third-person perspective (critical for identity formation). They’re truly able to speculate, considering possible outcomes of various choices. They’re able to entertain paradox, and empathise (as opposed to merely sympathising), and, well, think about thinking.

Of course, this has massive implications for faith development. In order to move from an inherited faith to an owned faith, abstract thinking provides the rails to run on. Most young and middle teens aren’t experienced at abstract thought – but the capability is there. I’ve contended for decades that my middle school ministry peers need to be superintentional about helping teenagers speculate about themselves, God, and the world. When we ‘take them to the shores of speculation’, we help them exercise their speculation muscle (it’s not really a muscle, but you understand), and further their faith development. In short: I’m convinced that a healthy understanding of the move to abstract thinking is the most important developmental reality, with the deepest implications, for youth workers to understand and integrate into our practice.

However, all of this developmental psychology stuff was still built on the assumption of a fully formed human brain, ready for action. And if we were misinformed about brain stuff, it was because it was considered unethical to study the brains of healthy children and teenagers. 

Brain Fact #2: When awake, the human brain produces enough electricity to power a small light bulb. 



For a long time, scientists have been studying adult brains – alive and dead, healthy and ill. But other than studying the brains of children and teenagers during autopsies, and the occasional brain surgery, very little was actually known about the processes of healthy pre-adult brains. All of that changed with the development and acceptance of the MRI (Magnetic Resonance Imaging). MRIs create slices or three-dimensional views of brains with no intrusion. First introduced in the mid-70s, the MRI was finally deemed a completely safe way to study healthy brains in the late 90s and an explosion of new discovery began.

A bunch of scientists started studying teenage brains. One of the leading scientists in this field is a guy named Jay Giedd (his findings, and others, are reported in an easy-to-read book I still recommend to all youth workers, called The primal teen: what the new discoveries about the teenage brain tell us about our kids, by Barbara Strauch). In his role as the chief of the unit on brain imaging in the child psychiatry branch at the National Institute of Mental Health, Giedd gets to look at child and teenage brains all day, every day. And in that context, he made a remarkable discovery that overturned hundreds of years of assumed reality: the human brain is not fully developed until after the teen years. In fact, the brain isn’t fully developed until the mid-20s. The areas which are significantly underdeveloped – missing, really – from the teenage brain, happen to coincide with the most frustrating aspects of teenage behaviour.

There’s more to the new discoveries on teenage brains than the ‘missing bits’, though. So let’s come back to those in a few paragraphs, and quickly cover some of the other stuff.



Neurons are the wiring of the brain. They’re the streets, overpasses and alleyways on which electrical charges travel, moving, in a very real sense, information around the brain. Without neurons, the brain is just a grey blob of useless gunk.

One of the new discoveries of the teenage brain is a better understanding of how neurons work. Important to this is the sheathing stuff called myelin. Simply put, myelin is a coating, or insulation, on the neurons that increases their conductivity. Children don’t have myelin on their neurons, adults do. You can do the maths on when the process of getting myelin – a process called myelination – occurs.

About six years ago, a group of middle school youth pastors I meet with annually asked an adolescent brain specialist to join us for a day. This was a guy who had studied hundreds of teenage brain MRIs, first-hand. He presented a bit of stuff (mostly about the effects of drugs on brain development); but we mostly peppered him with questions for hours. I remember very clearly one question and answer with this brain doc. I asked him: ‘We’ve all heard about myelination, and how it occurs in the young teen and middle teen years. And we all understand that myelination increases the speed at which information moves around the brain via neurons and neural pathways. But, could you give us a sense of what that increase would be?’

He was reluctant to answer my question, because he didn’t have a definitive response. So I gave him some multiple-choice options: ‘Well, would it be, like, a 50 per cent increase, or, like, a 100 per cent increase?’

His response: ‘Oh, no! It’s like a 200-times increase!’ (The maths: a 200-times increase is about a 20,000 per cent increase!). That’s some serious acceleration, baby! That little finding festered in my thinking for years, as I watched the assumed reality of incapable teenagers becoming commonplace in our cultural understanding. And now that I have a better sense of the difference between capability and norms, I’m finding some hope in the God-invented beauty of myelination.

Before I start sounding like too much of a science geek (‘too late!’ some are crying), let me connect all of this with the next finding, which has massive youth ministry implications. Ooh, I’m starting to get excited.



Like I said, neurons are the wiring of the brain; and together, they form neural pathways, which are the information superhighways of the mind. It’s pretty tough to count the neurons in a brain, but one estimate puts the number somewhere around 100 billion. (Seriously, doesn’t that make you want to give God a high-five?)

Here’s the crazy thing: in the couple of years leading up to puberty, the brain kicks into a neuron growth frenzy. Millions of additional neurons are added – way more than are needed, and way more than will be present when the brain reaches adulthood. At puberty, a toggle switch is flipped, and the process reverses itself. It’s almost as if some scythe-swinging meanie forages through the brain, slicing away millions of neurons, bringing the number back to the normal, adult quantity.

The truly fascinating thing about this is not the proliferation and winnowing themselves, but the process by which neurons are ‘chosen’ for elimination. Giedd calls it the ‘use it or lose it’ principle. In other words, the neurons used in the few years after the onset of puberty get to stay and play; and those neurons that aren’t used go to neuron heaven. They actually, literally, disappear (their parts repurposed or discarded).

In fact, Giedd – a scientist, not normally given to grandiose and hyperbole – goes as far as saying that by the end of the teen years, the brain is ‘hard-wired’ (his words, not mine) for how it will process information for the rest of its life. Dude! Seriously. Is this scientific finding not the encouragement   you need about the absolute importance of youth ministry? (And, from my little corner of the youth ministry world, it’s a pretty big affirmation of the importance of young teen ministry.) Hard freakin’ wired.

It’s this finding that has caused me to start saying that we youth workers need to be ‘champions of neural pathways’. What I mean by this is: we get to play a role in hardwiring the brains of teenagers in a way that will be locked in (at least to some degree) for the rest of their lives. So, what would have more life-long impact: learning faith facts, or learning to think about faith?

Really, this finding alone is enough to tell us that stuffing teenagers full of information is not the best use of our limited time and influence. Being a ‘champion of neural pathways’ means we are intentional about helping teenagers use those parts of their brains that will ‘hard-wire’ them for a lifetime of sustainable growth, inquiry, reflection and integration. 

We get to play a role in hard-wiring the brains of teenagers in a way that will be locked in (at least to some degree) for the rest of their lives 



Finally, the under-developed bits. Certainly, I’m boiling this down in a way that oversimplifies the depth of the findings. But, in general: the two most under-developed parts of the brain, prior to the mid-20s, are the temporal lobes, and the pre-frontal cortex (drop those words in at your next parents meeting, and you can sound fancy).

The temporal lobes are (duh!) behind the temples – just forward and up from the ears. They’re responsible, among other things, for emotional interpretation. They’re underdeveloped in most teenagers, and more under-developed in the average guy than the average girl.

The implication of this is that there’s a physiological reason for teenagers’ pervasive lack of emotional understanding and sensitivity (or, EQ, as some now call it). This lack of emotional understanding extends externally and internally. In other words, they are limited in their interpretation of others’ emotions, as well as their own.

Then there’s that big dog, the pre-frontal cortex (more commonly referred to as the frontal lobe). Often called the brain’s CEO, or the decision-making centre of the brain, the frontal lobe is responsible for a host of functions we associate with maturity: wisdom, decisions, prioritisation, self-regulation and self-governance, impulse control.

It’s easy to make quick deductions here: now we have a reason for why teenagers are so notoriously sucky at all those functions. Picture a stereotypical, archetypal teenager in your mind – lacking wisdom, making stupid decisions even when good data is available, acting on whims and impulses even when they know the results could be disastrous. It’s the teenager who drinks and drives, or texts while driving. It’s the teenager who has unprotected sex. It’s the teenager who chooses an action with horrible long-term results based merely on their want of a possible short-term, temporary benefit. And now we can say, ‘Well, of course! They’re not capable of anything else!’

Or can we? 

Brain Fact #3: Violent homes have the same effect on children’s brains as combat on soldiers. 



In the face of this adolescent brain development, a somewhat lone voice started pushing back. Dr. Robert Epstein, the former editor of Psychology Today, published a book called Teen 2.0 (originally released as ‘The case against adolescence’). Epstein raises questions about the assumptions behind all these new realities.

Essentially, Epstein questioned the implicit assumption of Giedd and others (an assumption that is clearly present in The primal teen) that teenage brains have always been the way we’re currently discovering them to be. Do teenagers act the way they do because of the limitations of their brains? Or, are teenage brains the way they are because our culture does not expect (or allow) them to use their brains like adults? It’s a chicken vs egg question, and the age-old nature vs. nurture debate.

Epstein even equates the nature assumption – that teenage brains have always been this way – with the kind of profiling that makes a certain grouping of people inferior based on their physiology, rather than their competency. He draws parallels to the once normal but now abhorrent assumptions about Jews, people of African descent, and women, who were assumed to be inferior based on their physiology (the average smaller brain size of women was used as a basis for the presumption that women were inferior to men, and less intelligent, which we now know is simply not the case). He contends that we’re already seeing findings of teenage brain development resulting in more isolation of teenagers from the adult world, more limitations on their freedoms, and more infantilisation (treating them like children).

It’s possible that Epstein is right. My two cents: I’m interested in pushing back. While I have no interest in living with my head in the sand, I want to see teenagers live into their capabilities and reach their full potential. 

Brain Fact #4: “Sphenopalatine ganglioneuralgia” is the scientific term for brain freeze. 



So where does all of this leave us, as youth workers who are trying to be responsive to the needs and lives of real teenagers?

Not long ago, I heard Andy Stanley give a talk on leadership where he proposed that leaders need to know the difference between problems to be solved and tensions to be protected. I don’t know that the tensions I’ve unpacked here need to be nurtured per se, but I do think we need to live in the tension.

In other words: I want to be paradoxically committed to being both counter-cultural, and to doing ministry in the real world that teenagers are living in. That means I study this stuff. I learn about brain development and its implications (particularly on faith development). I allow for bad decision-making (even creating space for it, since bad decision making is one of the best classrooms), plan for a lack of impulse control, and am gracious towards poor emotional interpretation. And I’m present to real teenagers living with real, under-developed, teenage brains.

But I don’t assume it has to be this way, or always will be. I hold onto hope and create space for teenagers to make good decisions. I provide opportunities and expectation for meaningful responsibility (the single-most influential factor in moving into adulthood, according to Epstein). I’m trying to move away from infantilisation, even in my language (not saying ‘kids’).

All of these new discoveries about teenage brains are fascinating. I welcome anything that can help me know and understand better the teenagers I’m called to. But I’m committed to doing ministry in the tension of reality and skepticism. Living in that tension keeps me on my toes, reminds me to be dependent on God, and drives me toward curiosity rather than blind assumption. 

Additional facts sourced from King’s College, London