Peer Influence Shapes Teens' Behavior in Distinct Ways

New study finds best friends impact emotional well-being, while popular peers influence social media use and appearance

Published on Mar. 2, 2026

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A longitudinal study from Florida Atlantic University reveals that peer influence is not a monolithic process - different types of peers exert influence over distinct domains of a child's life. The findings indicate that best friends primarily shape a child's internal emotional state and academic behavior, while popular peers set the standard for public image and social media engagement.

Why it matters

This research provides vital insights for intervention, as it shows that uniform solutions to address peer pressure may fail. The source of influence matters, and targeting the wrong peer dynamic could miss the problem entirely. Understanding how different peer groups shape adolescent behavior is crucial for developing effective strategies to support youth development.

The details

Researchers followed 543 students ages 10 to 14 in Lithuania, examining self-reports of academic performance, emotional well-being, problem behaviors, social media use and concerns about weight. The study found that 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. In contrast, popular peers shaped behaviors performed in view of others, such as social media use and weight concerns.

  • The study was conducted over the course of a semester, following students in middle school (grades 5-8) in Lithuania.

The players

Brett Laursen

A professor of psychology in FAU's Charles E. Schmidt College of Science and co-author of the study.

Mary Page Leggett-James

The lead author of the study and an associate researcher at Gallup, who completed this research as part of her doctoral dissertation at FAU.

René Veenstra

A professor of sociology at the University of Groningen in the Netherlands and a co-author of the study.

Goda Kaniušonytė

A professor at the Institute of Psychology, Mykolas Romeris University and a co-author of the study.

Florida Atlantic University

The university where the study was conducted.

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What they’re saying

“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, Professor of Psychology (FAU)

“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.”

— Mary Page Leggett-James, Lead Author and Associate Researcher (Gallup)

“Friendships are powerful because they are private and emotionally intense. 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.”

— Brett Laursen, Professor of Psychology (FAU)

“Peer influence is powerful, but it is not one-size-fits-all. 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.”

— Mary Page Leggett-James, Lead Author and Associate Researcher (Gallup)

What’s next

The researchers suggest that future interventions should target the specific peer dynamics that are shaping different types of adolescent behavior, rather than using a one-size-fits-all approach.

The takeaway

This groundbreaking study demonstrates that peer influence is a nuanced and specialized process, with best friends and popular peers exerting distinct impacts on a teen's internal emotional state, academic performance, social media use, and appearance concerns. Understanding these differences is crucial for developing effective strategies to support healthy adolescent development.