We’ve all been there. “I’m leaving home and I’m never coming back!” “It’s not just a phase, Mum.” Slammed doors. Smashed plates. My Chemical Romance t-shirts and “bold” eyeliner. If you haven’t guessed already, I’m referring to those golden teenage years. Whilst we may have given our parents a hard time, we may not be completely responsible for that increased phone bill.
When we’re born, our brains aren’t fully formed so the first few years of our existence involve an expansion of connections – synapses – between cells. Approximately 10,000 different connections are made between the hundred billion brain cells you were born with by the time you are six-years-old!
But during our teenage years, these numerous connections are trimmed down; the brain decides which connections are important enough to keep, and which can be let go, depending on how frequently each neural link is used. This process is called synaptic pruning. This process actually continues well after we stop calling people “teenagers” – some researchers believe this only ceases in our mid twenties, sometimes later! But sometimes this process can go wrong, leading to important connections being lost which could lead to psychiatric disorders such as schizophrenia.
The synapses that are kept are then subjected to a process called myelination, where the synapse is given a sheath that helps them transmit signals more quickly. That is why the teenage years are so critical to your future development! Skills and habits laid down at this point are likely to stay in the long run.
Interestingly, the prefrontal cortex is the last part of the brain to fully mature (or finish pruning). However, this is the part that allows us to be an adult – it controls our emotions and helps us to empathise with others. Therefore, if your prefrontal cortex isn’t functioning fully, you tend to be impulsive and insensitive to other people’s feelings. Sound familiar? Don’t worry though – as teenagers mature, the prefrontal cortex is used a lot more when making decisions, showing that they start to consider others when making choices.
What about that stereotype that teenagers are “hormonal”? Well stereotypes usually come from some truth! Teenagers are hypersensitive to pleasure; rewards such as the neurotransmitter dopamine release is at its peak during adolescence. Any action that causes dopamine release is positively reinforced, but the actions that cause the most dopamine release are usually associated with a stereotypical teenager – reckless driving, drug taking, and/or risk taking. Or in my case, 7 hours of dungeons and dragons on a Friday night – please don’t judge. This reward system is also closely harmonious with the brain’s social network, which uses oxytocin, a neurotransmitter that strengthens bonding between mammals. This causes teenagers to strongly associate social interactions with happiness and so constantly seek out social situations. This explains why we usually see a dynamic shift from kids being close to parents to teenagers having friends being their emotional centres.
So the next time the teenager in your life is threatening to throw a chair at you, just remember that parts of their brain are literally being destroyed. Cut them some slack, bro.