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

“So take the lead, take control, and try to think for your teenage sons and daughters until their own brains are ready to take over the job.”

Throughout the book, the author emphasizes the importance of active parental involvement in the adolescent years. Jensen argues that as teenagers’ brains are not fully developed, parents cannot step back at this crucial stage of development. Adolescents need guidance until they are capable of full responsibility and independence. The imperative verbs in this sentence epitomize the didactic tone of much of the book, and they suggest that Jensen sees parents as in need of almost as much guidance and direction as teenagers.

“Our best tool as they enter and move through their adolescent years is our ability to advise and explain, and also to be good role models.”

Jensen asserts that parents play a key role as mentors and guides to their teenagers. The author suggests that modeling good behavior and regular communication are essential tools in Supporting Healthy Brain Development During Adolescence. Her repeated use of the word “our” makes her seem part of the collective in an attempt to establish a connection between herself and her fellow parents.

“This is the last part of the brain to develop, and that is why you need to be your teens’ frontal lobes until their brains are fully wired and hooked up and ready to go on their own.”

As the frontal lobes are responsible for executive functioning, such as reasoning, assessing consequences, and organizing, adolescents tend to be lacking in these skills. Consequently, parents should anticipate these weaknesses and compensate for them through help and guidance. Jensen substitutes the role of parent for the frontal lobe using a literary technique known as metonym. By using the parent as a metonym for the frontal lobe, Jensen attempts to relate the parent-reader to the neuroscientific processes described in the book, both to enhance their understanding and to keep them engaged.

“Sex hormones are particularly active in the limbic system, which is the emotional center of the brain. That explains in part why adolescents not only are emotionally volatile but may even seek out emotionally charged experiences.”

Jensen explains that it is not simply an excess of hormones that causes typical teenage traits. Rather, it is the impact of those hormones on the highly-sensitive limbic system—the area of the brain responsible for emotions. Jensen uses the technique of polyptoton by repeated use of the words “emotion” and “emotionally,” with the effect that the most relatable element of this explanation is imparted to the reader, making the description of the limbic system more easily digestible.

“In order to understand why teenagers are moody, impulsive, and bored; why they act out, talk back, and don’t pay attention; why drugs and alcohol are so dangerous for them; and why they make poor decisions about drinking, driving, sex—you name it—we have to look at their brain circuits for answers.”

This passage highlights the book’s theme of Adolescence as a Misunderstood Development Stage. The language is highly sensational and moralizing and attempts to draw in a reader experiencing the same bewilderment that Jensen describes at the beginning of the book. The insertion of “you name it” invites the reader to project their own personal experiences alongside those worries described here, seemingly tailoring the book to their own lives, even while the advice remains general.

“The teenage brain is almost like a brand-new Ferrari: it’s primed and pumped, but it hasn’t been road tested yet. In other words, it’s all revved up but doesn’t quite know where to go.”

This simile highlights the power of the adolescent brain with its accelerated potential for learning and simplifies neuroscientific concepts for the non-expert reader. However, the author also implies that teenagers are like learner drivers who lack the ability to control the vehicle of which they are in charge.

“The frontal lobes are the seat of our ability to generate insight, judgment, abstraction, and planning. They are the source of self-awareness and our ability to assess dangers and risks, so we use this area of the brain to choose a course of action wisely.”

Jensen describes the crucial role the brain’s frontal lobes play in executive function. She asserts that the immaturity of the frontal lobes in teenagers explains their risky behavior, impulsivity, and lack of organizational skills. These emotive descriptions of “danger” and “risks” are deliberately juxtaposed with the image of a “wise” course of action. The use of the word “wisely” establishes a characteristic of Jensen as parental sage in the book.

“Multitasking is not only a myth but a dangerous one, especially when it comes to the teenage brain.”

The author suggests this misconception among teenagers is “dangerous” for more than one reason: Multitasking inhibits learning capacity when studying, but it can also prove fatal when adolescents are driving. This sentence is therefore an example of the sensationalizing that Jensen projects through the book. Seemingly innocuous activities are often transposed to the extreme of death, a pattern designed to keep the reader engaged.

“As a brain chemical messenger, dopamine helps motivate, drive, and focus the brain because it is integral to the brain’s reward circuitry. It’s the ‘I gotta have it’ neurochemical.”

Jensen frequently uses colloquial language to attempt to relate to the reader, as demonstrated with the use of “I gotta have it.” This example is particularly notable since it adopts the language of teenagers themselves, preempting Jensen’s recommendations to readers to teach their own teenagers the concepts described in the book.

“What scientists tell us is that insight depends on the ability to look outside oneself, and because that skill arises in the frontal and prefrontal lobes, it takes time to develop.”

Here, the author explores the way the immaturity of adolescents’ frontal lobes means that they are unable to see the wider picture. This is directly juxtaposed with the wide-ranging scope of the book. While the teenagers in question do not “look outside oneself,” the book ranges from neuroscience to the legal system to educational curriculum reform.

“Teenagers may look like adults, they 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 behavioral limitations are—is critically important.”

Exploring the theme of society’s misunderstanding of adolescents, Jensen highlights a misconception. The author believes it is essential to understand what adolescents are not capable of doing in order to protect them from danger and understand their mistakes. Her conclusion about what is “critically important” is an example of Jensen using subjective language to add a narrative to previously-established neuroscientific ideas about cognition, emotion, and behavior.

“‘Frequency’ and ‘recency’ are the key words here—the more frequently and the more recently we learn something and then recall it or use it again, the more entrenched the knowledge, whether it’s remembering the route between home and work or how to add a contact to your smartphone’s directory.”

Describing the learning process of the brain, Jensen explains how neural pathways become stronger the more we use them. Consequently, it is easier to retrieve information that we have recently used more than once. This passage employs meta references to the book’s own aims since it describes the process of learning while attempting to teach the readers at the same time. The author suggests parents should utilize this fact when they talk to their teenagers about potential dangers, while structuring the book such that readers themselves learn with “frequency” and “recency.”

“This is the time to identify strengths and invest in emerging talents. It’s also the time when you can get the best results from remediation, special help, for learning and emotional issues.”

Throughout the book, Jensen highlights the positive aspects of adolescence as well as its dangers. The teenage years are presented as a period of great learning potential. The positive nouns of “strengths” and “talents” establish a tone of optimism for a reader that remediates the sensationalist narratives about death and danger elsewhere.

“The growth of synapses makes teens sensation-seeking learning machines, but the fact that their brain signals can also easily slide off the tracks makes those growth spurts somewhat dangerous.”

Here, the author highlights the paradox of the teenage brain, which lends itself to the theme of adolescence as misunderstood. Adolescents are designed to seek out new information and experiences to eventually gain independence. However, the impulses that make teenagers learn also make them prone to experimentation with risky behavior or addictive substances. The image of sliding off the tracks calls back to the comparison of a teenage brain with a Ferrari, suggesting the risks of the Ferrari being “road tested.”

“The chief predictor of adolescent behavior, studies show, is not the perception of the risk, but the anticipation of the reward despite the risk.”

Jensen asserts that the highly reactive reward circuitry in teenagers’ brains is largely responsible for risky behavior. The inclusion of “studies show” provides an example of Jensen inserting objective fact into behavioral narratives throughout the book. The author explains that teenagers’ intense craving for pleasure outweighs the fear of “negative consequences.”

“The chilling realization about drug use and adolescence is this: The same brain processes that make negotiating the teen years so difficult make substance abuse more likely. An immature prefrontal cortex means less control over impulsive behavior, less understanding of the consequences, and fewer tools to stop the behavior.”

Here, Jensen explains that the immaturity of the prefrontal lobes means teenagers are less able to resist addictive substances and more likely to become addicted to them. By beginning the sentence with the word “chilling,” Jensen injects the ensuing discussion of “brain processes” with an emotionally-charged narrative that makes otherwise potentially bland explanations of a “prefrontal cortex” more engaging.

“Today’s teenagers and twenty-somethings make up the first generation of young people exposed to such a breathtaking number of electronic distractions, and they are therefore susceptible to a whole new host of influences.”

Difficulties in focusing are likely to be exacerbated by a diverse range of digital “distractions.” By describing the number of these as “breathtaking,” Jensen emphatically exits the realm of scientific explanation by inserting her own emotional response into the narrative.

“The compulsive need to be digitally connected happens on two levels, behaviorally and biochemically. Every ring, ping, beep, and burst of song from a smartphone results in an “Oh, wow” moment in the brain. When the new text message or post is opened, the discovery is like a digital gift; it releases a pleasurable rush of dopamine in the brain.”

Jensen explains the compelling nature of digital devices such as smartphones by explaining their effect on the brain using onomatopoeia (“ring, ping, beep”) that recreates the aural sensation for the reader. The “pleasurable rush of dopamine” she describes is similar to the impact of tobacco, drugs, or alcohol.

“Behavioral addictions are just as insidious as chemical addictions because they make use of the same brain circuits. This is why, whether it’s gambling, interacting on social media, or snorting coke, teenagers are particularly susceptible to the rush of good feelings that comes with stimulating the brain’s reward centers.”

The author explores the theme of unhealthy brain development by describing how addictive substances or habits create neural pathways in the brain. Her examples move from a seemingly ordinary situation of social media to a visceral description of “snorting coke” to once again alert the reader to the idea of a teenager “sliding of the tracks.” Jensen again emphasizes that teenagers are particularly vulnerable to addiction due to their brains’ highly reactive reward centers.

“Teenagers have always committed careless, impulsive acts, but the digital tools now at their disposal have exponentially magnified the dangers and certainly the consequences of those careless, impulsive acts.”

The idea of what teenagers “have always” done contributes to the occasional generalizations in the text (of teenagers as a homogenous group) for the purpose of simplifying the book’s conclusions for the reader. When teenagers unwisely post online, the results are seen by a wider audience, often resulting in more serious consequences. Her repetition of the words “careless, impulsive acts” attempts to emphasize this point to the reader.

“Over the past few years, scientists have slowly begun to realize that brain damage can result even from nonconcussive blows to the head. All it takes are repetitive strikes of moderate intensity. In other words, thousands of kids playing contact sports who have never had to sit out a game because of a concussion could be at risk of brain damage—brain damage that is going undetected and undiagnosed and will be likely to cause cognitive impairment later in life.”

The author clarifies that teenagers can suffer concussions without obvious accompanying signs such as blackouts. Consequently, the author suggests that many adolescents may have brain damage without realizing it. This adds to a litany of examples throughout the book of creating dangerous narratives about quotidian situations, emphasized here by the cautionary yet casual tone of the phrase “[a]ll it takes.”

“Teens, we now know, engage the hippocampus and right amygdala when faced with a threat or a dangerous situation—this is why they are prone to being emotional and impulsive—whereas adults engage the pre-frontal cortex, which allows them to more reasonably assess the threat.”

In her discussion of juvenile crime, Jensen explains that adults use their prefrontal lobes to moderate their “fight or flight” response in adrenalin-inducing scenarios. This passage exemplifies how Jensen simplifies scientific concepts for her reader: She transposes technical information into easily understood concepts of emotion and threat assessment.

“We know that because of their still-maturing frontal lobes, adolescents have trouble understanding the consequences of their decisions, and therefore they are impaired in their ability to assess things such as their representation, and the consequences of plea bargaining.” 

In her discussion of the criminal legal system, the author explains why it is important to have different processes for juveniles. Her use of the collective pronoun “[w]e” is designed to engage the reader in the processes of knowledge acquisition in the book, since it makes the assumption of shared knowledge between reader and author. Jensen points out that teenagers’ lack of executive functioning makes it difficult for them to make considered decisions during the trial process.