The Teenage Brain – Under Construction

I just finished The Teenage Brain by Dr. Frances E. Jensen, and if you’re raising or working with teenagers, it’s one of those books that helps everything make a little more sense.

Jensen is a neuroscientist and the mother of two teenage boys. Her book combines the science of adolescent brain development with the lived experience of navigating mood swings, risky decisions, and selective hearing. Her main point is both reassuring and challenging: teenagers are not mini adults. Their brains are still very much under construction, with the frontal lobe (responsible for planning, decision-making, and impulse control) not fully developed until the mid-twenties.

Teenagers are capable of incredible things: creativity, idealism, deep friendships, and rapid learning. But they are also more prone to take risks, struggle with impulse control (I call this “making bonehead decisions”), and misread social cues. Not because they’re lazy or reckless, but because their brains are literally still wiring themselves together.

This book reminded me that when a student forgets their homework three days in a row or makes a poor decision with friends, it’s not always defiance. Sometimes it’s biology. That doesn’t mean we let everything slide. But it does mean we lead with understanding.

Jensen also emphasizes how much the teenage brain is shaped by experience. Habits formed now — sleep routines, screen time, social interactions, substance use — have a lasting impact. Which means that even when it feels like they’re tuning us out, they’re still learning from what we model and what we reinforce.

One of the best things we can do for teenagers is to help them establish structure in the areas of their lives that are still developing. Clear expectations. Boundaries with tech. Space to talk without being judged. And a steady adult presence that says, “I understand that you are still developing… and I’m here for you.”

This year, I’m planning to share a few quick takeaways from The Teenage Brain — and also from The Anxious Generation by Jonathan Haidt — in my weekly emails to parents throughout the fall. I will try to include a short insight and a couple of practical action steps or discussion prompts. My goal is to help us support our teens through a season of growth.