We can all agree that the teenage years don't necessarily have the best reputation in terms of angst and confusion and just general hormonal chaos. But why is that exactly? When a teenager is going through all those bodily changes, it might be easy to overlook the busyness that is the teenage brain, but taking a closer look will surely explain many teenagers' sometimes seemingly strange behavior.
Scientists now know that while our brains are already about 95% full size when we are just six years old, the connections in a mature brain don't come around until our early twenties! That means all those neuron paths that allow us adults to make decisions by evaluating consequences and outcomes, haven't quite reached that development stage in teenagers yet. Furthermore, the connections are slow, physically speaking, because during the teen years axons are starting to form thicker myelin sheaths, which allow those neurons to pass messages back and forth faster. Teenagers' brains are also going through a stage called synaptic pruning, which has also been called a "Use it or Lose it" phase. Hence the argument for all those extracurricular activities!
Teenagers' mood swings and the infamous rebellion and risk-taking phases might be explained not only by their hormones but by the fact that they use their amygdalas, which are responsible for gut reactions, instead of their prefrontal cortices (more rational thinking) to determine emotional situations. One study showed that teens even judge the facial expressions of adults differently from how other adults perceive them. That could explain a lot of miscommunication!