"Late development of the frontal cortex in teenagers" or "Why does my teenager act brain-dead sometimes?"

Anyone who is the parent of a teenager has undoubtedly at times searched their memory to identify any incidences of dropping them on their heads as infants. What else could possibly explain their behavior? I'm convinced my own teenager, must have played bumper cars with the kitchen cabinets using his head (all on his mother's watch of course).

Turns out there's a perfectly valid reason that teenagers act the way they do. To understand it, we have to understand a little about evolutionary brain development.

Inside our skulls is a story of our evolution displayed the pigment of neurons (nerve cells) and their connections. Three distinct layers of brain structures trace a history of brain development. The "Reptilian Brain" which mainly consists of the brain stem. The "Mammalian Brain" which consists of mainly the Thalamus (a sensory relay station) and the Limbic System which is the seat of our emotions. Finally is the "Neocortex" or "new brain" which is where we humans come in. In this Neocortex the biggest portion (and the part that separates us from the "beasts of the field") is the Frontal Lobes. All of your executive reasoning, logic, and planning takes place in these frontal lobes.

From the time we are conceived till adulthood, our brain development retraces our evolutionary trail. Before and at birth, the reptilian brain is developed first, which controls our heart rate, breathing, digestion and an array of primitive reflexes for our protection and survival. With parent interaction comes the development of the mammalian brain with regulation of emotions, and non-verbal communication. The next step is walking and talking and development of the neo-cortex which continues and is refined throughout our lives.

Herein lies the rub, dear readers. Seems that the frontal lobes don't fully finish maturing until early to mid 20's. Which means a teenager is like a jet fighter plane, with a full tank of jet fuel (hormones) and the pilot is asleep at the wheel.

So the next time your teenager does something that makes you swear they were dropped on their head, respond with a little patience that only a fully developed frontal lobe can provide.