The Teenage Brain: A Neuroscientist's Survival Guide to Raising Adolescents and Young Adults

Neuroscience is the study of the nervous system and how it works. It combines various areas of science, including biology and psychology. Branches of neuroscience include cognitive (how neural responses affect psychological functions), affective (the neural responses involved in emotions), behavioral (the connections between the brain, behavior, and environment), and developmental (how the brain and nervous system develop). In recent years, technological innovation has led to significant advances in neuroscience. The development of brain imaging equipment, such as functional magnetic resonance imaging (fMRI) scanners, has enabled neuroscientists to learn more about the brain’s structure and function. Brain activity can be mapped, revealing how different areas connect with one another. Consequently, scientific understanding of brain processes such as memory, learning, behavior, and perception has improved.

Until recently, neuroscientific research has largely focused on the brains of infants and the elderly. The first few years of life are recognized as a crucial stage of learning and brain development. The brain rapidly changes as infants absorb new stimuli and achieve key developmental milestones such as walking and talking. Meanwhile, research into the elderly brain has sought a better understanding of degenerative brain processes, such as Alzheimer’s disease. It is only in the past few decades that more attention has been given to the adolescent brain. As a result, neuroscientists have identified unique chemical and structural features. They now recognize adolescence as a crucial stage of brain development, comparable to infancy.

Adolescents have long had a reputation as a challenging and difficult age group. However, advances in neuroscience have prompted a reevaluation of teenagers and their behavior. The traits that make teenagers appear deliberately contrary and oppositional are now recognized as the natural result of changes taking place in the brain. The adolescent brain is in a constant state of flux and activity as it prepares an individual for independence and adulthood. The brain works toward greater efficiency through synaptic pruning: a process where unused synaptic connections are eliminated. Myelination also takes place, insulating axons in order to speed up neural signals. Brains develop from the back to the front, and in adolescents, fMRI scans show that the frontal lobes and their connections to the rest of the brain are still developing. Also, as the teenage brain is primed to learn, it exhibits greater plasticity with increased sensitivity to experiences and the environment.

Neuroscientific research has also explained the reputation that teenagers have for staying up late and sleeping in. Scientists now know that teenagers release melatonin—the hormone that induces sleepiness—several hours later than adults. This delay affects the circadian rhythm, meaning that teenagers are wakeful for longer and still have melatonin in their systems at the time when most adults wake up. As Jensen points out in The Teenage Brain, teenagers are not inherently lazy. It is rather that early school start times force them into a routine that does not suit their bodies and brains. Consequently, they often suffer sleep deprivation.

A greater scientific understanding of the processes in the adolescent brain suggests that society needs to adjust its perception of teenagers. Adolescence is a key developmental stage during which teenagers cannot be expected to act like adults. Jensen and many other neuroscientists believe that more strategies should be created to support teenagers during these crucial years.