Peer Influences on Adolescent Decision Making

Abstract

Research efforts to account for elevated risk behavior among adolescents have arrived at an exciting new stage. Moving beyond laboratory studies of age differences in "cool" cognitive processes related to risk perception and reasoning, new approaches have shifted focus to the influence of social and emotional factors on adolescent neurocognition. We review recent research suggesting that adolescent risk-taking propensity derives in part from a maturational gap between early adolescent remodeling of the brain's socio-emotional reward system and a gradual, prolonged strengthening of the cognitive control system. At a time when adolescents spend an increasing amount of time with their peers, research suggests that peer-related stimuli may sensitize the reward system to respond to the reward value of risky behavior. As the cognitive control system gradually matures over the course of the teenage years, adolescents grow in their capacity to coordinate affect and cognition, and to exercise self-regulation even in emotionally arousing situations. These capacities are reflected in gradual growth in the capacity to resist peer influence.

Figure 1. The Stoplight driving game

In the Stoplight driving game, participants are instructed to attempt to reach the end of a straight track as quickly as possible. At each of 20 intersections, participants render a decision to either stop the vehicle (STOP) or to take a risk and run the traffic light (GO). Stops result in a short delay. Successful risk taking results in no delay. Unsuccessful risk taking results in a crash, and a relatively long delay. Summary indices of risk taking include (a) the proportion of intersections in which the participant decides to run the light, and (b) the total number of crashes.

Figure 2. Differential susceptibility of adolescents to peer influences on Stoplight task performance

Mean (a) percentage of risky decisions and (b) number of crashes for adolescent, young adult, and adult participants when playing the Stoplight driving game either alone or with a peer audience. Error bars indicate the standard error of the mean.

Figure 3. Brain regions showing an age by social condition interaction during Stoplight task performance

(a) Brain regions exhibiting an age by social condition interaction included the right ventral striatum (VS, MNI peak coordinates: x = 9, y = 12, z = -8) and left orgitofrontal cortex (OFC, MNI peak coordinates: x = -22, y = 47, z = -10). (b) Mean estimated BOLD signal change (beta coefficient) from the four peak voxels of the VS and the OFC in adolescents (adols.), young adults (YA), and adults under ALONE and PEER conditions. Error bars indicate standard errors of the mean. Brain images are shown by radiological convention (left on right), and thresholded at p < .01 for presentation purposes.

Figure 4. Behavioral and self-report correlates of Stoplight-related activity in the right ventral striatum (VS)

Resistance to Peer Influence correlated with Stoplight-related activity in the right ventral striatum (VS). Estimated activity was extracted from an average of the four peak voxels in the VS region of interest. Scatterplot of activity in the VS indicating an inverse linear correlation between self-reported resistance to peer influence (RPI) and the neural peer effect (i.e., the difference in average VS activity in peer relative to alone conditions, or βpeer − βalone).