credit: http://commons.wikimedia.org/wiki/File:Boy_driving.jpg
You’ve been stuck in traffic forever and are waiting in a long lineup at a red light. The light finally turns green and you start slowly moving, only to find that the light turns yellow as soon as you approach the intersection. Do you go for it and run the yellow (or maybe red!), or stop and wait again? And how does that decision change if a colleague or friend is in the car?
For adolescents, the attitude of a peer in the car dramatically changes the decision-making process. New research finds that differences in how individual teens’ brains control their inhibitions predict safer driving when a cautious peer is present in the car but the reverse is not true: Individual differences in response inhibition do not change risky behavior when a risky peer is present.
The new study – one of two new studies on adolescent risk-taking in the Journal of Cognitive Neuroscience – seeks to understand how individual neural differences interact with social pressures. Previous research has suggested that teens are more prone to risk-taking due to the rapid development of the brain’s emotional processing system while the cognitive control system is still immature. Specifically, teens show a range of activity within the right inferior frontal gyrus, a component of the prefrontal cognitive control system.
“The adolescent brain handles risky decision-making in similar ways to adults and children, generally relying on the same regions and processes,” says Jennifer Pfeifer of the University of Oregon. “However, the degree to which certain regions and processes are engaged during risky decision-making seems to vary, both with development and between individuals of the same age.”
The current models of adolescent risk-taking have not been able to fully interpret how these differences translate into patterns of decision-making, and are only just starting to directly consider the role of social context. The two new studies both use driving simulator tasks to better understand how adolescents handle risk.
Balancing peer pressure
“Slower development of cognitive control regions may not be the entire reason teens are prone to risk-taking; social context also seems to play an important role,” says Christopher Cascio of the Annenberg School of Communication at the University of Pennsylvania, the lead author of one of the new studies. “For example, teens may be prone to risk-taking in front of their friends but not in front of their parents. Therefore, we were interested in how social context interacts with the response inhibition network to predict adolescent risk-taking.”
Working with colleagues, including his adviser Emily Falk, Cascio recruited male adolescents, 16 to 17 years old, to take part in a driving simulator experiment. “The driving simulator was unique in that it allowed us to experimentally manipulate the social context while maintaining a real-world driving environment,” Cascio says.
First, the participants completed a test of their response inhibition – how well they can stop responding to a stimulus – while undergoing fMRI and also completed a survey about their susceptibility to peer pressure. A week later, they performed a series of simulated drives, during which an actor displayed either risky or cautious behavior. Additionally, the researchers “primed” the participants to think about risk norms.
“The male teen actors posing as one of the study participants arrived late to the study where they gave a risky or safe excuse for being late that involves their driving behavior,” Cascio explains. Then, the participants viewed a set of safe and risky driving videos with the teen actors and were asked to answer some questions. “The actors would prime the social norm by giving an answer that suggested that they were either a risky or cautious driver,” Cascio says.
The researchers found that increased activity associated with response inhibition lead to less risk-taking in those participants who had a more cautious peer in the simulator with them. But with the more risky actors, increased activity in the prefrontal control network did not reduce risky behavior. “Overall, it was a very interesting finding that indicates that both individual differences and social context are important predictors of risk,” Cascio says.
The research team was specifically interested in when teens drove through intersections with yellow and red lights. On average, participants drove through intersections while the light was red 21% of the time when they were driving with a peer, but the behaviors varied. Extremely cautious teens did not drive through any of the intersections during a red light, while the riskiest teen drove through intersections during a red light 63% of the time when he was driving with a peer. And participants drove through the red light significantly more when they drove with a risky peer (27%) compared to with a cautious peer (15%).
“From the perspective of a parent with adolescents, these results highlight the importance of social cues and risk-taking, which adolescents may not be consciously aware of,” Cascio says. “One potential intervention may be to teach adolescents to better recognize social situations or cues that lead to emotionally driven risk-taking, which may allow them to consciously engage cognitive control resources in order to make better decisions.”
An important next step for the research, Cascio says, is to examine neural activity associated with both response inhibition and reward within subjects and map that activity onto future risk-taking. The other study just published in the Journal of Cognitive Neuroscience begins to tackle that issue – looking at how neural responses to risky decision-making evolve over time.
Evolving risky behavior
“While some risk-taking is normal and even adaptive in adolescence, if parents are concerned about unhealthy levels or types of risk-taking, our research suggests that it would be best to intervene early – before patterns of risky decision-making become relatively more automatic and engrained.” – Jennifer Pfeifer
“A popular hypothesis about adolescent risk-taking is that heightened sensitivity to reward during adolescence leads teenagers to be more vulnerable to making bad or suboptimal decisions when faced with real-life gambles, like choosing to drink and drive, due to a disproportionately developed ‘hot’ motivational system compared with an underdeveloped ‘cold’ cognitive control system,” says Lauren Kahn of the University of Oregon. She and colleagues, including Jennifer Pfeifer, wanted to better understand what happens in the teen brain right before they make decisions, and how that might change over time.
Similar to in the Cascio et al., study, their team recruited teens, 14 to 16 years old, to complete a computer-based driving simulation game while undergoing fMRI scanning. The researchers instructed participants to drive as fast as they could as though they were trying to get to a party before their friends left. In each of a series of five runs, the drivers encountered 10 stoplights that turned yellow as they approached.
They had to then make a decision: whether to drive through the light and risk waiting a 6-second penalty for crashing, or to safely stop and wait the guaranteed 3-second penalty for stopping. “Importantly, this kind of split-second decision may recruit different processes than the ones which support more planned decision-making,” Pfeifer explains.
The researchers were specifically interested in brain activity in reward-processing regions such as the ventral striatum, as well as in right inferior frontal gyrus, which is associated with controlling and inhibiting behavior. The research team found that activity in the ventral striatum preceded risky decisions, while activity in the right inferior frontal gyrus preceded safe decisions.
This activity reflects the tradeoff between risk and reward. When faced with a risky decision, “self-regulation helps you override the attractiveness of the reward and choose the less risky option,” Pfeifer says. “Parents should realize that each decision their teenager makes reflects this competitive process, and presents an opportunity for them to choose wisely, especially if given the extra resources to engage self-regulation when necessary.”
It also means, she says, that when resources are running low, whether due to poor sleep or distraction, teens (like adults) may be less likely to self-regulate. Although in this study teens were making decisions alone, Pfeifer echoed the results from the Cascio et al., study, saying the presence of peers can dramatically alter the decision-making process.
For example, other recent research in her lab has found that after being socially excluded by peers, teens made more risky decisions when they thought those same peers were watching. In that case, more activity in the right temporal-parietal junction, a region associated with perspective-taking, was associated with increases in risky behavior.
Importantly, in the current study the researchers also found that over successive games played alone, activity in the right inferior frontal gyrus decreased when choosing to run the yellow light. “Our findings suggest the accumulation of experience with a particular kind of decision changes how the brain responds the next time you have to make that choice,” Pfeifer says. “As adolescents gain experience making similar decisions, over time the brain regions that support self-regulation are recruited less and less during risky choices.”
This has important implications for real-world decision-making. “While some risk-taking is normal and even adaptive in adolescence, if parents are concerned about unhealthy levels or types of risk-taking, our research suggests that it would be best to intervene early – before patterns of risky decision-making become relatively more automatic and engrained,” she explains.
Pfeifer and her team are currently studying risky decision-making across social contexts in early adolescents who have a history of adverse childhood experiences. “In general, early adolescent risk-taking has significant implications for long-term health outcomes,” Pfeifer says.
Youth who have experienced high levels of early adversity, such as those in the child welfare system, have disproportionately high rates of engagement in health-risking behaviors including drug use and risky sex,” she says. “By looking at brain activity during risky decision-making across social contexts, we hope to be able to enhance our understanding of which neurocognitive processes are most directly involved in reducing – or amplifying – risk-taking.”
-Lisa M.P. Munoz
