Linking Risk-Taking Behavior and Peer Influence in Adolescents

BOSTON—Researchers have shed light on how peer influence may increase risk-taking behavior in adolescents at the neural level, as reported at the 54th Annual Meeting of the American Academy of Child and Adolescent Psychiatry.

“One of the hallmarks of adolescent risk taking is that it is much more likely than that of adults to occur in groups,” said Jason Chein, PhD, Assistant Professor in the Department of Psychology at Temple University in Philadelphia. “There’s a peer influence that seems to play an especially important role in this heightened period of risk taking during adolescence.”

Risk-taking situations, Dr. Chein explained, prompt the need for deliberative thinking. In these situations, neuroimaging studies have revealed a common set of engaged brain regions, namely the anterior cingulate cortex, regions of the lateral prefrontal cortex, and regions of the posterior parietal cortex. These regions have been shown to be associated with cognitive control—working memory tasks, logical reasoning, planning, and regulating impulses. When these brain regions have been more highly activated, participant decisions tend to favor rational, utilitarian outcomes.

However, in situations that prompt the participant to engage in some form of emotional thinking, the medial prefrontal cortex, posterior cingulate cortex, and medial orbitofrontal cortex are activated. These brain regions are closely tied to the actions of the brain stem’s neurotransmitter systems and have been linked to the processing of emotions, of social information, and of the consequences of reward and punishment. When these regions are relatively greater in activation, the outcome of decision making tends to be in favor of reward-based demands rather than those that are purely rational.

With these data, Dr. Chein presented a simplified framework for decision making in adult brains composed of two networks: a highly interconnected cognitive control network that biases decisions in favor of rational outcomes and a socioemotional network that biases decision making toward reward-based demands. The cognitive control network can regulate the behavior of the socioemotional network, allowing adults to often make decisions that favor utilitarian outcomes. However, neither of these systems is fully matured during adolescence, and each one develops along different timetables, Dr. Chein stated. Therefore, these two underdeveloped networks and their differing rates of development pave the way for heightened risk taking during adolescence, which is further compounded by the influence of peers.

HEIGHTENED RISK TAKING DURING ADOLESCENCE

Dr. Chein explained that in the MacArthur Foundation’s Juvenile Culpability Study, led by Laurence Steinberg, PhD, of Temple University, 935 individuals ages 10 to 30 were tested on a variety of basic intellectual functioning measures. The researchers found a gradual and monotonic development of the cognitive control system during the course of two decades. In contrast to easy tasks, in which there was no difference in the amount of time persons took to plan their actions, difficult problems resulted in an increasing amount of time spent planning as participants aged. In addition, a self-report measure showed that impulse regulation increased with age, while impulsivity decreased with age.

“This linear, gradual development of the cognitive control network can be differentiated from the way in which it appears that the socioemotional system develops,” Dr. Chein stated. “The socioemotional system looks like it undergoes major change right at the onset of early adolescence. This probably has to do with the proliferation of dopamine receptors in the limbic system and the hormonal changes at the onset of puberty. Unlike the pattern of the cognitive control system, we think this system shows a curvilinear, quadratic trend, with increasing arousal into midadolescence, which then turns into decreasing arousal as you move from midadolescence onward into adulthood.”

PEER INFLUENCE COMPOUNDS EFFECT

Dr. Chein also posited that social feedback arouses the socioemotional network during adolescence, which further biases decision making in favor of rewarding, social-processing outcomes, rather than rational, cognitive outcomes. A self-report measure in the MacArthur study, which asked whether it was easier or harder for peers to change one’s mind, found an increasing resistance to peer influence with age.

Dr. Chein and colleagues developed a simulated driving experiment called the stoplight driving task. Participants were encouraged to drive through a series of intersections as quickly as they could to reach a radio station that was giving out money, with the knowledge that their peers were either present or absent.

Two versions of this study were conducted, the second being different from the first in that fMRI was used to detect the neural underpinnings of the participants’ decisions, the intervals between successive intersections were varied, and the participants were told that their peers were either evaluating their progress from another room or not present at all.

All other measured factors being equal, there were no age-related differences between adults and solitary adolescents with respect to riskier driving decisions in the first version of the simulated game. However, adolescents found themselves in simulated car crashes more often when they performed the task with their peers present than when they performed the task alone. This difference was not as great, but it reached an intermediate level among college-age participants, and no difference was observed in crash rates between adults either in the presence or in the absence of their peers.

One clue that points to a link between peer influence and the socioemotional network during adolescence is that the same brain regions involved in the processing of reward, punishment, and emotion are also engaged in social contacts that are devoid of any obvious reward or emotional component, Dr. Chein said. A second clue relates to pubertal hormonal changes and social processing.

“At the onset of adolescence, there’s a rise in gonadal hormones,” Dr. Chein stated. “This stimulates a proliferation of receptors for oxytocin—perhaps best known for its role in pair bonding and social bonding. And so we might argue that the increase in oxytocin during early adolescence stimulated by pubertal hormonal changes may increase the salience of their peer social relations. This thereby might affect how the socioemotional network will be aroused in the context of peers.”

In addition, preliminary results from the fMRI study showed that brain regions that make up the cognitive control network were activated in both the peer presence condition and in the peer absence condition, while brain regions associated with the socioemotional network were activated more strongly in the peer presence condition.

—John Merriman

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