Understanding the Adolescent Brain
What is Adolescence?
‘Adolescence,’ as an entity, did not exist until the Great Depression of the 1930’s when child labourers lost their jobs. Because they needed to be productively occupied, fourteen to seventeen-year-olds in North America were enrolled in high schools (Jensen, p. 17). Prior to this, the transition from late childhood to young adulthood was marked by sexual maturation or ‘puberty’, and the assumption of adult roles and responsibilities, although most young adults remained in close proximity to their parents, slowly acquiring social and economic independence.
As the years of education have been further extended by the complexities of modern jobs, so too has the period of adolescence. Today, teens and young adults have many years of increasing independence without much parental oversight, and without many responsibilities. This has brought new challenges and new dangers for young people, as well as considerable conflict with their parents.
Although there are significant challenges for parents, teachers, teens, and young adults during the adolescent years, there is also much to celebrate, including passionate debates, new friends, new ideas, energy, vitality, and creativity. Understanding the developmental imperatives of this stage may help to offset the frustrations.
Neuroscience
Researchers have studied adolescence extensively, examining sexual and social behaviour, and mental health, but it is only in the past ten years or so, that scientists have been studying the neuroscience of adolescence. They have discovered that the adolescent brain is in a period of distinct growth and development, that it is qualitatively different than the child or adult brain, and that this physiological developmental phase spans the ages of twelve and twenty four.
There is a certain irony in the fact that we thought adolescence was a socially constructed, modern phenomenon, whereas, it now appears to be a significant developmental process, guided by evolutionary requirements.
Hormones
While academics have discussed adolescence in sociological terms, there has been a popular myth that hormonal changes in puberty or ‘raging hormones’ are to blame for everything from teen explosiveness, to lack of focus, poor judgement, thrill seeking, and rebelliousness. Although there is an increase in sex hormones in puberty, these are now thought to be somewhat less significant and explanatory than other events taking place in the teen brain.
So what’s going on in the teen brain?
An overabundance of grey matter
According to Frances Jensen, a neuroscientist at the University of Pennsylvania and former Professor of Neurology at Harvard Medical School, the teen brain has an abundance of grey matter which is “the neurons that form the basic building blocks of the brain” (Jenson, p. 26). It also has an excited limbic system which is the part of the brain affected by hormones and adrenaline, and is involved in sexual and emotional behaviour, language and memory. Excitation is a key element of learning (Jensen, p. 56), as well as of sexual arousal and explosiveness (Jensen, p. 46). The abundant and supercharged grey matter, together with the sensitive and excited limbic system means that teens have an extraordinary capacity to learn, to be engaged in new experiences, to be curious, inventive, and creative.
Teens and young adults are the generation that brings new ideas and innovation to the world. They are best equipped to adapt to change, and it makes sense, in terms of evolution, why the powerful teen brain has developed to undertake these tasks.
The brain is the only organ that changes as it matures, rather than just getting bigger. This is because the brain has plasticity, which means it is changed or molded by experience. Significantly, the experiences and subsequent changes to the brain in adolescence, have a powerful impact on adult ways of thinking, feeling, and engaging with the world.
An undersupply of white matter
While the teen brain has an abundance of grey matter, it has an undersupply of white matter (myelin), “the connective wiring that helps information flow efficiently from one part of the brain to the other” (Jensen, p. 26). In addition, the brain matures from back to front and it is the frontal lobe which governs executive function, judgment, insight, planning, and impulse control. This is the “source of self-awareness and our ability to assess dangers and risk” and “choose a wise course of action.” The frontal lobe is the last to develop and is, therefore, least mature and least connected. The teen brain “is only about 80% of the way to maturity” (Jensen, p. 36).
Jensen writes, “the mood swings, irritability, impulsiveness, and explosiveness, inability to focus, or follow through, the temptation to use drugs and alcohol and engage in other risky behaviour are due to the immaturity of adolescents’ brains-they are, in fact, not firing on all cylinders” (p. 37- 38).
In addition, teens and young adults are frequently unable to respond to crises in helpful ways. They sense danger but panic, and are unable to react appropriately. They can’t problem solve, especially when they have been consuming alcohol and drugs. “Cross the immature limbic system with a teen’s loosely connected frontal lobe, and you have a recipe for potential disaster” (p. 46). Given this information, it isn’t surprising that accidents are the leading cause of death in children aged fifteen to nineteen.
Four Qualities of the Adolescent Mind
According to Dan Siegel, a professor of psychiatry at UCLA School of Medicine, brain changes in adolescence set up four qualities of mind which are very different from childhood, which are necessary to create new ways of being in the world, but which have negative possibilities (Siegel, p. 7). If adolescence is positively and fully realized, it can set a healthy and dynamic course for adult life. If not, the consequences can be catastrophic.
Novelty seeking: an increased drive to try new things and engage more fully in life creates an openness to change, a fascination for living, and a desire to design unique ways of doing things; there is also a potential for “sensation seeking and risk taking,” which result in dangerous behaviour.
Social engagement: there is a “drive for social connection” which can lead to the creation of supportive peer relationships; if these peer relationships are additions to important relationships with parents and other adults, it’s a very positive development, but if peer relationships result in a rejection of adults, and their knowledge and wisdom, there is a large potential for serious problems.
Emotional intensity: with the “enhanced vitality” and energy of the teen brain, adolescents can acquire enormous learning and skills but if there is intense emotion which is unchecked, it can produce “impulsivity, negativity, and a resistance to change.”
Creative exploration: adolescents’ “new conceptual thinking and abstract reasoning allow them to think ‘out of the box,’ to innovate, and to question the status quo” which can lead to a lifetime of exploration, creativity, and zest but can also lead to “a crisis of identity, vulnerability to peer pressure, and a lack of direction and purpose” (Siegel, pp7-9).
How to reduce the risks?
Dr. Jensen says, “teenagers may look like adults, may even think like adults in many ways, and their ability to learn is staggering but knowing what teenagers are unable to do-what their cognitive, emotional, and behavioural limitations are-is critically important” (p. 64).
Communicating with adolescents is the key to modifying and influencing their behaviour and inclinations; engaging them, enjoying them, and appreciating them will make a difference.
Teens and young adults need to be constantly reminded of danger.
Realize that the college years are still years of vulnerability; don’t overestimate their abilities and judgment; keep connected.
Get to know your teen’s friends; make them welcome in your home.
Problem solve, review possible situations, and what to do.
Remind them frequently to call you if they are in trouble, no matter what they have done.
TIP
Every trained swimmer and life guard knows that, when facing a current or undertow, you don’t attempt to fight it head on, but swim at a 45 degree angle to reach the shore. It saves energy, and increases the probability of success.
Resources:
Frances E. Jensen, M.D., with Amy Ellis Nutt, The Teenage Brain, A neuroscientist’s survival guide to raising adolescents and young adults, Collins, 2015.
Daniel J. Siegel, M.D., Brainstorm: The power and purpose of the teenage brain, Penguin, New York, 2013.
About the Author
Janet Morrison, M.A., C. Psych Assoc. is a psychological associate in private practice and a senior lecturer at the Factor-Inwentash Faculty of Social Work, University of Toronto. Over the past 30 years she has assessed, treated and supervised treatment of children in long-term care, as well as, consulted for Children's Aid Society and group homes across Ontario.