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Why are teenagers so impulsive?

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📓 The short answer

Teenagers are more impulsive because their brains are still developing faster access to the parts responsible for self-control, while emotion and reward systems are already firing on all cylinders. Hormone spikes, limited life experience, and peer pressure also contribute to increased impulsivity.

📚 The long answer

Acting on impulse can lead to some dangerous outcomes — and some funny ones too:

Teenagers are well-known for acting impulsively. Maybe you made some regrettable choices as a teen, like drinking alcohol to excess, driving way too fast, or getting a tattoo you regret.

Here are some leading reasons why researchers believe teenagers act so impulsively:

Reason #1: The teenage brain isn't fully developed yet.

You've probably heard that the brain doesn't finish developing until your 20s, but let's dig a little deeper into what exactly that means.

Acting impulsively means you take action quickly with little thought into all the potential outcomes. But before you act, you've got to decide to act. At risk of oversimplifying the human brain, making good decisions comes down to weighing the reward (with your striatum) and weighing the risks (with your prefrontal and frontal cortexes).

The striatum tracks how much you like something, i.e. how much reward you get for doing something.

• Example brain thought: "I like eating sugary cereal."

The prefrontal and frontal cortexes help you consider the future outcomes of doing things, i.e. how they might affect others and your future goals.

• Example brain thought: "If I eat three bowls of cereal, I'll get a stomachache and none will be left for my little sister."

You can see how the prefrontal and frontal cortexes are critical for good judgement. And, to be clear, teenagers have access to good judgement — but their challenge is that the pathways between these reward and risk centers of the brain aren't well-connected yet.

Neurons send and receive signals from one another. Signals are received at the dendrites, move along the axon, and pass to the next neuron via the terminal buttons.

In teenage brains, this "wiring" hasn't been fully developed. Specifically, not all their neurons have been insulated with fatty substance called myelin, which allows signals to travel faster throughout the brain.

Myelination happens throughout development, from the back of the brain to the front. That makes the prefrontal and frontal cortexes among the last areas of the brain to undergo myelination. So even if a teen knows something is a bad idea, their brain might not deliver that insight fast enough to stop them.

Additionally, parts of the brain responsible for emotions, like the amygdala, develop earlier. That means strong emotions like fear, excitement, and anger more accessible than calm, rational thinking.

This "maturational gap" theory suggests that teenagers are more sensitive to immediate rewards and emotions and less sensitive to the parts of their brain that provide long-term thinking and self-control.

Reason #2: Hormonal changes promote reward-seeking behaviors in teenagers.

Hormonal changes that influence impulsive decision-making in teenagers.

Testosterone levels, especially in males, spike dramatically during puberty. It's linked with increased impulsivity, sensation-seeking, and risk-taking. Just check out this striking set of graphs that highlight the correlation between arrests per 100,000 by age (top) and testosterone levels in males by age (bottom).

Dopamine, a key neurotransmitter in the brain’s reward system, is also very active in teenagers. The teenage brain is more sensitive to dopamine than adults, making teens more likely to seek out dopamine-releasing activities, like alcohol and drug use, reckless driving, and unprotected sex.

Reason #3: Teenagers lack common sense due to inexperience.

The teenage years are a time of significant learning and exploration as the adolescent begins to flex their independence, explore passions, and seek new experiences. As a result, the brain is designed to encourage more risk-taking.

But teenagers haven't been on Earth that long, so they have less life experience to draw upon when making decisions. So part of teenager impulsivity may come down to a lack of wisdom.

Reason #4: Social desires to fit in with a group can lead teenagers to make impulsive decisions.

Teenagers' strong desire to be a part of a group also influences their impulsive natures.

Teens often surround themselves with peers that share common interests. The presence of friends amplifies activity in the brain's reward centers, making risk-taking adventures, like drug use and fast driving, seem more exciting. In moments like that, it's hard to pump the breaks on an impulsive decision when your friends are egging you on.

Teens lacking strong social bonds with friends, teachers, and parents have also been shown to be more impulsive. When teenagers lack supportive, positive relationships with their peers, they may end up making less thoughtful decisions. Teens aged 13–15 who report negative feelings toward their teachers also show higher levels of impulsivity. Finally, lacking support and having a negative relationship with a parent is also associated with increased impulsivity and lower self-control.

--- Thanks for reading this week's newsletter! If you have any thoughts, questions, or favorite GIFs, my inbox is always open. Just hit reply to send me a note! :) ​ All my best, Caitlin ​Click here to read five facts about Caitlin​

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​Sources for this week's newsletter​

🌐 Wikipedia article of the week

​Mooning​

"Mooning is the act of displaying one's bare buttocks by removing clothing, e.g., by lowering the backside of one's trousers and underpants, usually bending over....

Moon has been a common shape metaphor for the buttocks in English since 1743, and the verb to moon has meant 'to expose to (moon)light' since 1601. As documented by McLaren, "'mooning', or exposing one's butt to shame an enemy ... had a long pedigree in peasant culture" throughout the Middle Ages, and in many nations."

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👀 Catch up on other curious questions

• ​Why do humans kiss each other?​​
• ​Why can't chickens fly?​​
• ​What causes the "butterflies in your stomach" feeling?​​

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