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April 1, 2005
Vol. 62
No. 7

The Biology of Risk Taking

For help in guiding adolescents into healthy adulthood, educators can look to new findings in the fields of neuroscience and developmental psychology.

The Biology of Risk Taking- thumbnail
I celebrate myself,And what I assume you shall assume,For every atom belonging to me as good belongs to you.—Walt Whitman, Leaves of Grass
Adolescence is a time of excitement, growth, and change. Whitman's words capture the enthusiasm and passion with which teenagers approach the world. Sometimes adolescents direct this passion toward a positive goal, such as a creative essay, an art project, after-school sports, or a healthy romance. At other times, they divert their passions to problematic activities, such as drug experimentation, reckless driving, shoplifting, fights, or school truancy.
Why do adolescents take risks? Why are teens so passionate? Are adolescents just young adults, or are they fundamentally different? Advances in developmental psychology and neuroscience have provided us with some answers. We now understand that adolescent turmoil, which we used to view as an expression of raging hormones, is actually the result of a complex interplay of body chemistry, brain development, and cognitive growth (Buchanan, Eccles, & Becker, 1992). Moreover, the changes that teenagers experience occur in the context of multiple systems—such as individual relationships, family, school, and community—that support and influence change.
Educators are in a pivotal position to promote healthy adolescent growth. Understanding the biological changes that adolescents undergo and the behaviors that result can provide the foundation for realistic expectations and effective interventions.

The Impact of Puberty

The hormonal changes of adolescence are often considered synonymous with puberty. The word puberty comes from the Latin term pubertas, meaning “age of maturity.” As implied by the word's etymology, the changes of puberty have long been understood to usher in adulthood; in many cultures, puberty and the capacity to conceive continue to mark entry into adulthood. In contrast, puberty in modern Western culture has become a multistep entry process into a much longer period of adolescence (King, 2002).
Hormonal changes of adolescence include adrenarche, gonadarche, and menarche (Dahl, 2004; King, 2002). Adrenarche refers to the increased production of adrenal hormones and occurs as early as age 6–8. These hormones influence skeletal growth, hair production, and skin changes. Gonadarche refers to the pulsatile production of a cascade of hormones and contributes to driving the growth spurt and genital, breast, and pubic hair development. Menarche refers to the beginning of girls' menses, which generally occurs late in girls' pubertal development.

The Stages and Ages of Puberty

The clinician J. M. Tanner developed a system for classifying male and female pubertal growth into five stages (Tanner I–V). In the 1960s, he identified a trend of progressively earlier age at menarche across cultures (1968). Since then, investigators have identified similar trends of earlier arrival of other markers of puberty, such as breast and pubic hair development (Herman-Giddens et al., 1997). These trends have diverged across race in the United States, with proportionately more African American girls experiencing earlier-onset puberty than white girls. The implications of these trends have ranged from debates over the threshold for premature puberty to investigations into factors that contribute to earlier-onset puberty (Kaplowitz & Oberfield, 1999).
Boys who enter puberty at an earlier age experience certain advantages, including higher self-esteem, greater popularity, and some advances in cognitive capabilities (King, 2002). These same boys may also be more likely to engage in risk-taking behavior, possibly because they often socialize with older boys (Steinberg & Morris, 2001). Girls, on the other hand, often have more problems associated with earlier entry into puberty, including lower self-esteem and elevated risk for anxiety, depression, and eating disorders. These girls are also more likely to engage in risk-taking behaviors, including earlier sexual intercourse.

Don't Blame It On Hormones

In the past, hormones were believed to be in a state of great flux, which presumably caused adolescents to be dramatic, erratic, intense, and risk-prone. Evidence suggests, however, that only minimal association exists between adolescent hormone levels and emotional/behavioral problems (Buchanan et al., 1992; King, 2002). Youth with higher levels of hormones do not appear to be at higher risk for emotional or behavioral problems (Dahl, 2004).
Today, adolescent specialists view emotional intensity and sensation-seeking as normative behaviors of adolescence that are more broadly linked to pubertal maturation than to hormone levels. Pubertal stage rather than chronological age is linked to romantic and sexual pursuits, increased appetite, changes in sleep patterns, and risk for emotional disorders in girls. One group of investigators studying teen smoking and substance use found that increased age had no correlation with increased sensation-seeking or risky behavior (Martin et al., 2002). Instead, they determined that pubertal maturation was correlated with sensation-seeking in boys and girls, which, in turn, led to a greater likelihood of cigarette smoking and substance use.
Pubertal stage was clearly linked to difficulties that Derek began experiencing in school. He had been a solid student in 6th grade who scored in the average range and generally turned his homework in on time. He socialized with a group of same-age friends and was teased occasionally because he was skinnier and shorter than his peers. By 7th grade, however, he had begun his growth spurt. He was now a few inches taller and had developed facial hair. Although he appeared more confident, he also seemed more aggressive and was involved in several fights at school. He began to spend part of his time with a few 8th grade boys who were suspected of writing graffiti on a school wall.
A teacher who had a good relationship with Derek took him aside and spoke with him about the change in his behavior from 6th to 7th grade. Derek was able to talk about his own surprise at the changes, his wish for more respect, and his ambivalence about entering high school—he was worried about what teachers would expect of him. Derek and the teacher agreed to talk periodically, and the teacher arranged for Derek to meet with the school counselor.

The Adolescent Brain

Neuroscientists used to believe that by the time they reached puberty, youth had undergone the crucial transformations in brain development and circuitry. Data obtained through available technology supported this view, identifying similar brain structures in children and adults. The adolescent brain seemed entirely comparable to the adult brain.
This view of adolescent brain development has undergone a radical shift during the last decade, with the identification of ongoing brain changes throughout adolescence, such as synaptic pruning and myelination. People have the mature capacity to consistently control behavior in both low-stress and high-stress environments only after these neurobiological developments are complete. This maturation does not take place until the early 20s.
Synaptic pruning refers to the elimination of connections between neurons in the brain's cortex, or gray matter. In the 1990s, researchers determined that during adolescence, up to 30,000 synapses are eliminated each second (Bourgeois & Rakic, 1993; Rakic, Bourgeois, & Goldman-Rakic, 1994). The removal of these redundant synaptic links increases the computational ability of brain circuits, which, in turn, enhances a function intricately connected to risk taking: the capacity to regulate and rapidly stop activity. Myelination, which refers to the wrapping of glial cell membranes around the axon of neurons, results in increased speed of signal transmission along the axon (Luna & Sweeney, 2004). This facilitates more rapid and integrated communication among diverse brain regions.
Synaptic pruning and myelination, along with other neurobiological changes, facilitate enhanced cognitive capacity as well as behavioral control, also known as executive function. Executive function is the ability to interact in a self-directed, appropriate, organized, and purposeful manner. The prefrontal cortex plays a vital role in guiding executive function, which is also influenced by such areas of the brain as the hippocampus (which coordinates memory), the amygdala (which coordinates emotional processing), and the ventral striatum (which coordinates reward-processing). The prefrontal cortex is less mature, however, in young adolescents than in adults.
Given these three factors—an inability to completely regulate and refrain from certain activities, an absence of fully integrated communication among the various regions of the brain, and a less developed prefrontal cortex—it is not surprising that adolescents biologically do not have the same capacities as adults to inhibit their impulses in a timely manner.

Biology and Thrill-Seeking

By their mid-teens, adolescents appear to have achieved many decision-making abilities seen in adults (Steinberg & Cauffman, 1996). In fact, studies have found that teens can identify the same degree of danger in risky activities that adults can—driving while intoxicated, for example (Cauffman, Steinberg, & Woolard, 2002). However, certain methodological flaws in studies of adolescents may have prevented investigators from accurately assessing adolescent risk taking (Steinberg, 2004). These flaws include evaluating teens individually rather than in the context of a group, within which most risk-taking behavior occurs; asking teens to evaluate theoretical situations, which may not sufficiently represent the challenges of actual situations; and evaluating teens in settings that reduce the influence of emotion or induce anxiety rather than generate the exhilaration associated with risk taking.
One result of these flaws may be that measures of adolescents' cognitive abilities—particularly their evaluation of risk—do not adequately reflect their actual cognitive and emotional processes in real time. Consequently, teens appear to have the cognitive capacities of adults yet continue to engage in more risky behaviors.
The emotional lives of adolescents also appear to shift during these years. Adolescents seek more intense emotional experiences than children and adults do. They appear to need higher degrees of stimulation to obtain the same experience of pleasure (Steinberg, 2004). Developments in an area of the brain called the limbic system may explain this shift in pursuit and experience of pleasure (Spear, 2000).
Ongoing cognitive development and emotional shifts result in a biologically based drive for thrill-seeking, which may account for adolescents' continued risk taking despite knowledge of the accompanying hazards. Some interventions attempt to reduce the potential for risky behavior through external means—laws and rules, for example—rather than placing sole emphasis on the practice of educating teens in risk assessment (Steinberg, 2004). Others have considered teens' ability to reason well in “cool” circumstances but their failure to do so when in “hot” situations that arouse the emotions. Providing adolescents with sufficient scaffolding, or a good balance of support and autonomy, may be particularly important (Dahl, 2004).
This kind of scaffolding would be especially effective with a student like Shauna. Shauna raised the concerns of school faculty soon after she started 9th grade. Her attendance, class participation, and assignment completion were erratic. She had also run away from home during the summer and received a warning for shoplifting. The school counselor learned that Shauna's parents had separated over the summer and that her mother was struggling to set limits in the absence of Shauna's father. The school counselor, several teachers, and the vice principal decided to meet with both of Shauna's parents.
Although tension between the parents was evident, both parents agreed that Shauna should come home immediately after school instead of going to the mall, which she had recently started to do. Both parents also felt strongly that she needed to regularly attend school and complete assignments. The parents arranged to meet with Shauna together to discuss their shared expectations for her. The parents and teachers agreed to stay in contact with one another regarding Shauna's attendance and homework. The group also decided that a home-based reward system might encourage Shauna's success at school. The reward system would involve outings to the mall and to friends' homes, with incrementally less adult supervision and more autonomy as she continued to succeed.

The Role of Educators

  • Ensure that schools provide adolescents with vital support. School bonding provides a protective influence for youth. The mentorship of a teacher can make the difference in a teen's course.
  • Keep a long view. Researchers have found that the benefits of successful interventions may disappear for a few years in adolescence to reappear in later adolescence (Masten, 2004). Other teens are late bloomers whose troubled earlier years are followed by success.
  • Prioritize your concern. The junior who has never been a problem and gets into trouble once is at a different level of risk than the 7th grader who has a long history of worrisome behaviors, such as fights, school truancy, mental illness, exposure to trauma, loss of important adult figures, or absence of stable supports. Act early for adolescents with long histories of risk taking.
  • Remember that puberty is not the same for all teens. Some adolescents enter puberty earlier than others, giving them a perceived social advantage as well as possible disadvantages. There may be a biological drive to risk taking in teens, which is expressed by individual teens at different ages.
  • Remember that teens are not adults. Having the scientific evidence to support the view that teens are not adults can be helpful to educators working with families, adolescents, or other professionals who may have un-realistic expectations for adolescents.
  • Take advantage of adolescent passion. Direct adolescents' enthusiasm toward productive ends. A teen's passion can become a bridge to learning about such topics as music theory, history, politics, race relations, or marketing.
  • Reduce risk with firm structure. Although teenagers dislike rules, they generally thrive in reasonable, supportive environments that have a predictable, enforced structure. For example, an authoritative stance in parenting—which reflects firmness coupled with caring—has repeatedly been found to be the most effective parenting strategy. Continue to maintain school rules and expectations, even when an adolescent continues to break the rules.
  • Collaborate to solve problems. Working with risk-taking adolescents can be demanding, taxing, and worrisome. Talk regularly with colleagues for support. Contact appropriate consultants when your concern grows. Teens who see teachers collaborate with other adults benefit from these healthy models of problem solving.
It's important for educators to keep in mind that up to 80 percent of adolescents have few or no major problems during this period (Dahl, 2004). Remembering that most adolescents do well can encourage the positive outlook that educators need to effectively work with youth during this exciting and challenging time in their lives.

Bourgeois, J-P., & Rakic, P. (1993). Changes of synaptic density in the primary visual cortex of the macaque monkey from fetal to adult stage. Journal of Neuroscience, 13, 2801–2820.

Buchanan, C. M., Eccles, J. S., & Becker, J. B. (1992). Are adolescents the victims of raging hormones? Psychological Bulletin, 111, 62–107.

Cauffman, E., Steinberg, L., & Woolard, J. (2002, April 13). Age differences in capacities underlying competence to stand trial. Presentation at the Biennial Meeting of the Society for Research for Adolescence, New Orleans, Louisiana.

Dahl, R. E. (2004). Adolescent brain development: A period of vulnerabilities and opportunities. Annals of the New York Academy of Science, 1021, 1–22.

Herman-Giddens, M. E., Slora, E. J., Wasserman, R. C., Bourdony, C. J., Bhapkar, M. V., Koch, G. G., et al. (1997). Secondary sexual characteristics and menses in young girls seen in office practice. Pediatrics, 99, 505–512.

Kaplowitz, P. B., & Oberfield, S. E. (1999). Reexamination of the age limit for defining when puberty is precocious in girls in the United States. Pediatrics, 104, 936–941.

King, R. A. (2002). Adolescence. In M. Lewis (Ed.), Child and adolescent psychiatry (pp. 332–342). Philadelphia: Lippincott Williams & Wilkins.

Luna, B., & Sweeney, J. A. (2004). The emergence of collaborative brain function: fMRI studies of the development of response inhibition. Annals of the New York Academy of Science, 1021, 296–309.

Martin, C. A., Kelly, T. H., Rayens, M. K., Brogli, B. R., Brenzel, A., Smith, W. J., et al. (2002). Sensation seeking, puberty, and nicotine, alcohol, and marijuana use in adolescence. Journal of the American Academy of Child and Adolescent Psychiatry, 41, 1495–1502.

Masten, A. S. (2004). Regulatory processes, risk, and resilience in adolescent development. Annals of the New York Academy of Science, 1021, 310–319.

Rakic, P., Bourgeois, J-P., & Goldman-Rakic, P. S. (1994). Synaptic development of the cerebral cortex. Progress in Brain Research, 102, 227–243.

Spear, P. (2000). The adolescent brain and age-related behavioral manifestations. Neuroscience and Biobehavioral Reviews, 24, 417–463.

Steinberg, L. (2004). Risk taking in adolescence: What changes, and why? Annals of the New York Academy of Science, 1021, 51–58.

Steinberg, L., & Cauffman, E. (1996). Maturity of judgment in adolescence. Law and Human Behavior, 20, 249–272.

Steinberg, L., & Morris, A. S. (2001). Adolescent development. Annual Review of Psychology, 52, 83–110.

Tanner, J. M. (1968). Early maturation in man. Scientific American, 218, 21–27.

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