Why Your Teen Thinks They Know Everything

Posted February 2, 2015 by

As a parent of a teen, you try to help your son or daughter make good decisions.  You provide guidance. You give your child facts.  You explain the pros and cons. You talk to other parents. You think about how you felt when you were a teen, and the consequences you suffered when you made poor decisions. You think you have set your teenager up for success.

But then you find out that your teen has taken none of your advice and has done exactly what they wanted to all along!  Moms and dads, while this is frustrating and upsetting, there is a reason teens behave this way.  A significant part of your teenager’s brain, the prefrontal cortex, is undeveloped.

In fact, the prefrontal cortex is not fully developed until age 25! This is why, even after you explain the dangers and consequences, your teen may still make poor choices.  Her prefrontal cortex isn’t helping her, and so she all too often makes impulsive, “Woo-hoo, this sounds like fun,” decisions.

What is the Prefrontal Cortex?

The prefrontal cortex is typically referred to as the “CEO of the brain.”  Another way to think about it is like the brakes on a car.  The thing with teens is that they get the gas (the impulses), but they have a faulty brake system (an undeveloped prefrontal cortex).

The prefrontal cortex is responsible for:

1. Planning Ahead

Developed prefrontal cortex: “I have a lot going on this week; I better not schedule anything else.”

Undeveloped: Your son asks you if he can go to two concerts this week. He has two tests on Friday, a term paper due, and a big history project. Obviously, he is not planning ahead.

2.  Managing Emotions and Delaying Responses

Developed: You’re driving and someone cuts in the lane before you. You feel like ramming into their car, but you control yourself.

Undeveloped: You’re making dinner, and your daughter walks past. She had a tough day at school. You ask her if she wants a salad. She yells back, “Whatever, MOM!” and slams the door. She is not managing her emotions or delaying her responses.

3.  Empathy

Developed: You’re having lunch with a friend; you can tell she is exhausted and discouraged before she even opens her mouth.

Undeveloped: You’ve had a long day. You walk in the door, and tell your son that you are exhausted and need help with dinner. Because he is 14, he does not accurately read or understand the emotions of others; so he says, “Mom, I always help you. Why are you so mad?” when you are not mad at all—you just want help making dinner.

4.  Self-awareness

Developed: You come home from work and snap at your daughter. Twenty minutes later, you apologize because you realized that you were tired and took out your frustration on her.

Undeveloped: You are trying to have a discussion with your son. You calmly ask about his weekend plans. He gets all worked up and responds, “I don’t know, Mom!” You ask one more question, and he blows. You say, “Why are you so upset?” He yells, “I’m not upset; you’re the one who’s upset!” He is not aware how he comes across.

5.  Morality/ Conscience

Developed: You get pulled over for speeding, and the police officer asks you if it’s an emergency. You hesitate for a second, and then say no.

Undeveloped: Your daughter wants to go to the party because a guy she likes is there. You ask her if the parents are going to be home. She lies and says yes. She does not feel bad that she lied. She only feels bad if she gets caught. Morality and conscience are flaky during the teenage years, especially when opportunity knocks.

6.  The Big Picture/ Cause and Effect

Developed: You know that if you are going to be successful in work, you need to be reliable and trustworthy. You know that if you do not follow through with a client, you will lose that client.

Undeveloped: Teenagers often don’t consider the big picture—the cause and effect—so they act impulsively. Megan is angry with Lisa because Lisa likes her ex-boyfriend. She spreads gossip about Lisa all over school. Megan didn’t think about how that could backfire on her. Now, Lisa is spreading rumors about Megan. And Megan’s friends stop calling and start hanging out with Lisa.

Even though your teenager thinks they can make grown-up decisions on their own, they can’t. There are some major holes developmentally. Your teenager needs you to help them think through all of their actions and consequences.

Don’t let the grown-up body fool you. Your teenager is still a work in progress and their brain is still developing.  They need your guidance and protection throughout these critical years.


Colleen O’Grady specializes in encouraging and empowering mothers of teenagers, especially teen daughters, to live their highest and best life. From her coaching programs to her therapy sessions, she has helped thousands of mothers and teenage girls uncover their true purpose in life, create more happiness, and move to a place of inner peace. Find out more at www.poweryourparenting.com.

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