understanding the teen brain


Brain Maturation
In contrast to other animals, humans are characterized by being born very immature and are nearly helpless for many years.  At birth the human brain in particular is immature and only 25% of adult size.  By age one the brain is still well below adult size.  Humans have a long childhood during which the brain continues to develop and language and culture are assimilated.  In contrast, apes have a brain that is almost adult sized by their first birthday and they are self-sufficient at an age when human children remain dependant on parental care.

If the slow brain development of a long childhood separates us from apes, what are the implications of what we now know about brain development for successfully traversing adolescence and attaining emotional and social maturity?

Studies of child and adolescent cognitive development reveal that different areas of the brain mature at different rates.  The prefrontal cortex area that controls executive functions is the last part of the adolescent brain to fully develop with changes occurring through age 25 or older.  The prefrontal cortex regulates the most sophisticated areas of cognitive function including: planning, setting priorities, organizing thoughts, suppressing impulses, and weighing the consequences of one’s actions.  In childhood through the late teens there is both growth and pruning of brain connections with unused connections being discarded and those that have been developed, e.g. for language, music, mathematics or playing video games, becoming more abundant and efficient.

Early, Middle and Late Adolescence
Recognition that the adolescent brain is not fully adept at making mature judgments and controlling emotional reactions can help us devise strategies to assist teens to successfully move through early, middle and late adolescence.

Rapid physical growth and the beginning of sexual maturation characterize early adolescence (approximately age 11-13).  Typical concerns relate to the emergence of sexual feelings, body-image and looks, and concerns and worries about normalcy.  Early adolescence is a time when social interaction with parents declines, strong peer group relationships develop, often with the same sex, and the boundaries of independence are tested.  Cognitive functioning is characterized by concrete rather than abstract thinking, a focus on self and personal situation, unrealistic career goals, risk taking, lack of impulse control, testing the limits of authority, and beginning to develop a value system.

In middle adolescence (approximately age 14-18), peer groups are highly important and identification with them helps to affirmation self-image.  This is often a time of peak conflict with family values and demands.  The importance of peer group relationships may take the form of conformity in values, dress, behavior and the joining of groups, e.g., clubs, teams, and gangs.  Teens whose friends engage in deviant and risky behaviors such as smoking, drinking, or taking drugs are more likely to take part in those same unhealthy behaviors.  In middle adolescence there is increased preoccupation with sex, testing of ability to attract partners, pairing off, sexual experimentation and risk taking that tends to be self-centered and exploitative. 

Cognitive functions in middle adolescence are characterized by more ability for abstract thought, increasing intellectual activity and competence, more realistic vocational aspirations, more realistic perception of long-range consequences, but an increased sense of competence and invulnerability may lead to increased risk taking. 

In late adolescence (approximately age 19-24), teens cognitive abilities are characterized by more capability of abstract thought, ability to set limits, delay gratification and compromise.   They should have a better-developed conscience, more self-discipline, be more practical and future-oriented, and have greater realism in setting educational and vocational goals.  Late adolescents should have less concern about, and more comfort with, their body image.  Interpersonal relationships with family are likely to improve, peer group relationships become less important but more comfortable and individual relationships become more stable, caring, committed and less exploitative.

The heightened levels of hormones in adolescence intensify emotions and lead teens to seek stimulation and excitement.  Thrill seeking, together with an immature ability to make safe considered choices (especially when influenced by other teens), may lead to risky behavior relating to drugs, sex, and driving.  Brain development proceeds independent of hormones in that delayed puberty does not slow it nor does early puberty speed up brain development.

Use of some drugs may have adverse consequences for brain development and functioning.  There is evidence that early teenage use of marijuana impairs brain cognition and makes driving risky.  Young adults who became users before they were age 16 performed poorly on tests assessing the executive brain functions that are responsible for planning and abstract thinking as well as understanding rules and inhibiting inappropriate behavior.  Early and heavy use of marijuana is also associated with IQ loss.

Implications: What’s an Adult to Do
Dr. Joan Adler, Director of Adolescent Medicine and Family Planning at Temple Children’s Hospital in Philadelphia advises adults to help add what the teen brain lacks: structure, organization, time management and good decision-making.  Inappropriate behaviors should be disciplined with immediate consequences but love, patience and understanding are needed too.

An excellent introduction to adolescent brain issues is available at the U.S. Department of Health and Human Services, Office of Population Affairs, Office of Adolescent Pregnancy Programs (OAPP), Adolescent Family Life (AFL) OAPP Self-Directed Modules > OAPP Adolescent Brain Development available at: (

Family and community support and good communication with teens is fundamental to helping them go through adolescence and successfully attaining emotional and social maturity.  The following advice about communication is excerpted from the OAPP Adolescent Brain Development section “Creating a Safe Environment to Encourage Communication.”

Establishing rapport, providing clear boundaries, and allowing the adolescent control to make autonomous decisions, helps build trust with adolescents and sets a positive environment for sharing. Some useful strategies to encourage communication are:

  • Be an "active listener" and comment on what you think you heard. Ask open-ended questions that do not convey judgment.

  • Demonstrate an understanding of the adolescent's culture.

  • Be positive and have an upbeat tone of voice.

  • Be clear and detailed when giving instructions or providing information.

  • Demonstrate an understanding of the adolescent’s culture.

  • Promote self-esteem and self-respect. Teens with positive self-worth are less likely to be influenced by negative peer pressures.

  • Offer guidance that addresses the adolescents’ problem, behavior, or concern

Regarding the last point, develop an action plan to help the teen change any bad behavior. Ask the teen for input. Also, talk to the teen about strategies they can use in difficult situations. Discuss hypothetical scenarios such as what he/she can do if they are in a group and someone offers them drugs, alcohol, or cigarettes; they are pressured to have sex; or offered a ride by someone who has been drinking or using drugs. Helping the adolescent come up with a plan before they get into a situation will improve their chances for making better decisions; and hopefully avoid getting into dangerous situations.

A Word of Caution
Although the teen brain is thought to lead to high-risk behavior, for example in sports, driving and drug use, experts observers caution against blaming all adverse teen behavior on brain immaturity, noting that everyone is responsible for his or her own actions. Epstein asserts that teen turbulence is not inevitable, and that it is a creation of modern culture. (See Epstein, Robert. "The Myth of the Teen Brain." referenced below.)  According to Epstein “…we also know from extensive research both in the U.S. and elsewhere that when we treat teens like adults, they almost immediately rise to the challenge.  We need to replace the myth of the immature teen brain with a frank look at capable and savvy teens in history, at teens in other cultures and at the truly extraordinary potential of our own young people today.” 

Dahl has pointed out that “Puberty itself seems to increase the appetite for a specific type of emotional experi­ence: surges of arousal and cravings for exhilaration…”

“Fortunately, these emotional and motivational changes at puberty-these igniting passions-do not lead only to bad outcomes: Sex, drugs, loud music, and reckless behavior are not the only ways to activate the kinds of high-intensity feelings that are so appealing to adolescents. The efforts necessary to achieve a goal or to face a challenge can also become sources of positive, high-intensity feelings. And strug­gling to overcome adversity or to master a skill can also lead to inspired actions and the high-intensity feeling that can come from achieving a much-desired goal.  So these igniting passions can be aligned in healthy ways-in the service of high­er goals.” (See Dahl RE. Adolescent Brain Development: a Period of Vulnerabilities and Opportunities referenced below.)

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Additional Resources on Adolescent Brain Development

The Search Institute has identified 40 Developmental Assets that can serve as building blocks for healthy development that are available at:

Adolescent Growth and Development, Virginia Polytechnic Institute Publication 350 – 850, 2008: This website explores adolescent growth and development in three different areas: physical development, cognitive development and psycho-social development.

Developing Adolescents: A Reference for Professionals, American Psychological Association, 2002: This reference, takes an in depth look at many areas of Adolescent Development, including physical, cognitive, emotional, social and behavioral development.

The Adolescent Brain: A Work in Progress: National Campaign to Prevent Teen Pregnancy: This online document focuses on the Adolescent Brain and includes information on the physical changes the brain experiences during Adolescent development.

Brain Basics: Know Your Brain, National Institute of Neurological Disorders and Stroke: This illustrated website takes an in-depth look at the human brain and covers topics ranging from brain geography to a more specific look at the individual parts of the brain and their function.

Anatomy of the Brain, American Association of Neurological Surgeons: This in-depth, online resource from the American Association of Neurological Surgeons, covers brain anatomy by listing all of the brain’s parts and discussing their roles within the brain.

Brain Facts: A Primer on the Brain and Nervous System Society for Neuroscience: Steinberg L. Risk Taking in Adolescent: What Changes and Why? Ann NY Acad Sci 1021:51-58, 2004. This document covers the anatomy of the brain, the health problems found in the brain and the diagnostic methods that have been found to treat those challenges, among other things.

Building a Better Teenager: A Summary of What Works in Adolescent Development: This Child Trends research brief summarizes “what works” in adolescent development by examining the influences of their peer group and family during adolescence.

Ways to Promote Positive Development of Children and Youth: This Child Trends Research to Results Brief explores ways to promote the positive development of children and youth by examining the “5 Cs of positive youth development.”

McLean Study Shows Greater Cognitive Deficits in Marijuana Users Who Start Young This study is by Staci A. Gruber, PhD.

This article reports on a study that showed that young adults who started using the drug regularly in their early teens performed significantly worse on cognitive tests assessing brain function than did subjects who were at least 16 when they started smoking.

In this study by M. H. Meiera, et. al., in Proceedings of the National Academy of Sciences of the United States of America, persistent cannabis users show neuropsychological decline from childhood to midlife:

Cheryl L Sisk & Douglas L Foster, The neural basis of puberty and adolescence, Nature Neuroscience  7, 1040 - 1047 (2004.)

Giedd JN, Blumenthal J, Jeffries NO, et al. "Brain development during childhood and adolescence:
a longitudinal MRI study." Nature Neuroscience, 1999; 2(10): 861-3.

Baird AA, Gruber SA, Fein DA, et al. "Functional magnetic resonance imaging of facial affect recognition in children and adolescents." Journal of the American Academy of Child and Adolescent
38(2): 195-9. 1999.

Frontline: Inside the Teenage Brain. PBS. WGBH Educational Foundation. 2002. Available at:

Dahl RE. Beyond Raging Hormones: The Tinderbox in the Teenage Brain. Cerebrum:
The Dana Forum on Brain Science
. 5 (3):7-22. 2003.

Dahl RE. "Adolescent Brain Development: a Period of Vulnerabilities and Opportunities."

Casey BJ, Jones RM, Hare TA. "The Adolescent Brain." Ann NY Acad Sci 1124: 111-126. 2008.

Walsh D. "Why do they act that way? A survival guide to the adolescent brain for you and your teen." New York: Free Press, 2004.

Giedd JN. "Structural Magnetic Resonance Imaging of the Adolescent Brain." Ann NY Acad Sci 1021:77-85. 2004.

Sylwester, R. (2007) The Adolescent Brain: Reaching for Autonomy. Corwin Press.

Blakemore, Sarah-Jayne. "Brain development during adolescence." Education Review. Spring 2007.

Epstein, Robert. "The Myth of the Teen Brain." Scientific American. June 2007.

Goudarzi, Sara. "Study: Why Teens Don't Care." LiveScience. Sept. 7, 2006. (Aug. 12, 2008)

Hotz, Robert Lee. "Teenage Brains Seem Set for Recklessness, Yet Tend to Avoid Risk." Wall Street Journal. Nov. 30, 2007.

Hotz, Robert Lee. "Teenage Brains Seem Set for Recklessness, Yet Tend to Avoid Risk." Wall Street Journal. Nov. 30, 2007.

Kotulak, Ronald. "Teens Driven to Distraction." Chicago Tribune. March 24, 2006.,0,6601169.story

Kowalski, Kathiann M. "What's Inside the Teenager Brain." Current Health. November 2000.'S%20INSIDE%20THE%20TEENAGE%20BRAIN.html

Leimbach, Dulcie. "For Teenagers, a Tweak on 'Just Say No'." New York Times. June 20, 2005. (Aug. 12, 2008)

"Parents Just Don't Understand Lyrics." Sing365. (Aug. 12, 2008).'s-Just-Don't-Understand-lyrics-Will-Smith/147028ACAB35DB3C48256BCD00086EAF

Suplee, Curt. "Key Brain Growth Goes on Into Teens." Washington Post. March 9, 2000. (Aug. 12, 2008).

“Teenage Brain:  A Work in Progress”, National Institute of Mental Health, NIH Publication No. 01-4929, January 2001.

Wallis, Claudia. "What Makes Teens Tick?" Time. May 10, 2004. (Aug. 12, 2008).,9171,1101040510-631970,00.html

Weinberger, Daniel R. "A Brain Too Young for Good Judgment." New York Times. March 10, 2001. (Aug. 12, 2008).

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