Exploring how best friends and popular peers influence adolescent behavior

As children enter adolescence, peers become a dominant force in their lives. With adult supervision waning, teens look to agemates for guidance on how to act, think and fit in. But who matters most –friends or the popular classmates? A groundbreaking longitudinal study from Florida Atlantic University reveals that peer influence is not a monolithic process. Instead, different types of peers exert influence over entirely different domains of a child's life.

Researchers at FAU and collaborators at Mykolas Romeris University (Lithuania) conducted a long-term study to directly compare these two sources of influence. The study, published in the journal Development and Psychopathology, is the first to simultaneously compare the relative impact of best friends versus classroom norms, which are driven by popular classmates. The findings indicate that while best friends primarily shape a child's internal emotional state and academic behavior, popular peers set the standard for public image and social media engagement.

The investigators followed 543 students ages 10 to 14 (middle school in Lithuania is fifth through eighth grade) across a semester, examining self-reports of academic performance, emotional well-being, problem behaviors, social media use and concerns about weight. Participants also identified their best friends and classmates they considered popular. Popularity norms described classmate behaviors in each domain, weighted by popularity scores.

This is the first study to put best friends and popular peers in the same model and ask, 'Who matters more, and for what?,'"

Brett Laursen, Ph.D., professor of psychology in FAU's Charles E. Schmidt College of Science

The findings revealed a striking pattern. Best friends primarily shaped a child's internal emotional states and academic behaviors, whereas popular peers set the standard for public image. Specifically, best friends were the primary influencers for behaviors reflecting internal dysfunction and maladjustment, including emotional problems, lack of emotional clarity, problem behaviors, and low school achievement. Popular peers, by contrast, shape behaviors performed in view of others. Teens emulate high-status classmates in terms of social media use and weight concerns.

"Peer influence is too often treated as a broad, undifferentiated force, but our findings show it is actually highly specialized. Adolescents are discerning; they look to their inner circle for emotional support and to the influencers and class leaders for social cues on how to present themselves to the world," said Mary Page Leggett-James, Ph.D., lead author and associate researcher at Gallup, describing results from her doctoral dissertation at FAU. "Put differently, in the social economy of a middle schooler, best friends deal in the 'private currency' of emotions and adjustment, while popular peers control the 'public market' of social media and appearance."

The study suggests that adolescents use different mental calculations to navigate their social world. Friendships are based on reciprocity and intimacy, which promote shared experiences and emotional states. In contrast, peer groups are organized hierarchically. Conformity through public-facing behaviors like social media use and body image are important to maintaining status in the group. Thus, youth are not just blindly following others, they are using social strategies tailored to specific social settings.

"Friendships are powerful because they are private and emotionally intense," Laursen said. "Teens confide in their best friends. That closeness can provide support, but it can also amplify struggles. Anxiety, disengagement from school, or acting out can spread between friends and have a snowball effect. Appearance and online behavior play out on a public stage. Popular students set the standard. Others follow because that is what earns approval in the wider peer group."

The research offers vital insights for intervention. Because different peers shape different forms of maladjustment, uniform solutions may fail.

"Peer influence is powerful, but it is not one-size-fits-all," said Leggett-James. "Too often we treat peer pressure as if it comes from one place. But the source of influence matters. If we target the wrong peer dynamic, we risk missing the problem entirely. To reduce emotional distress or academic problems, we need to focus on friendship dynamics and help adolescents build positive peer connections – not try to ban or break up friendships. At the same time, issues tied to social media and body image require shifting status norms. When popular students display healthier, more realistic standards, they can redefine what classmates consider normal."

Co-authors are René Veenstra, Ph.D., professor of sociology at the University of Groningen, Netherlands; and Goda Kaniušonytė, Ph.D., professor at the Institute of Psychology, Mykolas Romeris University.

The research was supported by the European Social Fund under a grant agreement with the Research Council of Lithuania, and the state budget-funded project Establishment of Centers of Excellence at Mykolas Romeris University, implemented under the Centers of Excellence Initiative of the Ministry of Education, Science and Sports of the Republic of Lithuania.