The last decade has yielded an unprecedented amount of new science relating to the unique strengths and weaknesses of the adolescent and young adult brain. It is now crystal clear that when it comes to the brain, adolescents are not simply adults with fewer miles on them. In fact, the brain is the last organ in the body to mature, and is finally completed in most people in the mid to late twenties.
As a mother of two teenage sons, with a day job as a neurologist and neuroscientist, I marveled at the transformation that overcame my children as they crossed the threshold into adolescence. Being a neuroscientist, I was also well equipped to delve more deeply into the literature. What I uncovered was nothing short of astonishing. After sharing my synthesis of the literature in a series of Teen Brain 101 talks, I compiled this knowledge into a recently published book.
The newly discovered facts about the adolescent brain have application to parenting, the legal system, and mental health, but the most relevant domain for this information rests in the field of education - specifically in high school and college.
It turns out that the teen brain is essentially a "learning machine." That is, it has greater "synaptic plasticity" - the ability of the synapses responsible for learning to be modified, or molded, by experience - than the adult brain.
But the increased synaptic plasticity is only one of the teen brain's defining features. Research shows that adolescent brains are not yet as fully internally connected as in adulthood and that the last place to fully connect is the frontal lobe area, which is the brain region devoted to executive function, impulse control, empathy, and judgment. Neurons connect across brain regions by sending long processes from region to region. In order for the signals to conduct rapidly, these tracts have to be insulated much like electrical wires in our households. The insulation that nature uses is a fatty substance called myelin. Functional magnetic resonance imaging (fMRI) and other advanced imaging have shown that this process gradually proceeds from the back of the brain to the front over the course of the first two-and-a-half decades of life. Thus, we know, the risk-taking behavior of teens is largely due to the lack of rapid access to the modulating influence of the frontal lobe.
On the other hand, the emotional areas of the brain, which sit further back and include the amygdala and limbic system, are indeed almost fully connected in the teen years, resulting in a relative overbearing influence of the emotional areas without full impulse control of the frontal lobes.
Another unique issue for the adolescent is the sleep cycle. Sleep deprivation can negatively affect learning and synaptic plasticity, yet teenagers are notorious for keeping late hours and being nearly impossible to rouse the next morning. There is a biological basis to this behavior: the circadian clock sets itself a couple of hours later during the adolescent years. Melatonin release in the brain triggers sleepiness, and this release occurs closer to midnight in teenagers compared with earlier in adults. Because a sleep-deprived brain functions less well than a well-rested brain, this knowledge raises questions about the value of early morning academic endeavors - even about the starting time of school.
The high school and college years are an incredibly important time in brain development, when the "scaffolding" for later life is being constructed. Research has shown that even your IQ can change in your teen years. However, this enhanced plasticity may have a downside. It is somewhat ironic that teens' ability to reflect, to have clear insight, is not well developed at this point in life, and this results in young people taking risks that can imperil their brain health. Indeed, substance abuse, such as binge drinking and daily cannabis exposure, can cause more injury to the adolescent brain and leave long-lasting effects compared with the adult brain. Furthermore, neuroscience reveals that adolescents can get addicted more easily than adults.
This is only a partial list, of course. But I hope the point is clear: As parents and educators, the more we know about the teen brain, the more we can help teens thrive in this crucial stage of development. Through my research, it also became clear that teenagers are highly data-driven and have a great deal of respect for facts. They won't necessarily follow a request, but it is important to show them "the data." This was a central impetus for me in writing my book. Having real data and facts to back up one's discussions with teenagers about healthy development is essential as we help them navigate through to adulthood.