Who Really Shapes Teen Behavior: Best Friends or the Popular Crowd?
Ask a parent what worries them most about their adolescent's peer relationships and they will probably name one of two things: the wrong crowd or a bad influence best friend. What they may not realize is that these two sources of social pressure operate through completely different psychological channels - and targeting the wrong one could make an intervention miss entirely.
A longitudinal study published in Development and Psychopathology followed 543 students between ages 10 and 14 across a semester in Lithuania, simultaneously measuring the influence of both close friends and popular classmates. The findings show a clear division: best friends primarily shape internal emotional states and academic behaviors, while high-status peers set the public-facing norms that govern social media use and body image concerns.
A Split in Peer Influence That Previous Research Missed
Most studies of peer influence in adolescence treat it as a single force - kids conform to peers, full stop. This study is the first to put both sources of influence into the same statistical model and ask which matters more, and for what.
"This is the first study to put best friends and popular peers in the same model and ask, 'Who matters more, and for what?'" said Brett Laursen, professor of psychology at Florida Atlantic University's Charles E. Schmidt College of Science.
Participants identified their best friends and the classmates they considered most popular. Popularity norms for each domain - academic performance, emotional well-being, problem behaviors, social media use, and weight concerns - were calculated from classmate reports, weighted by each classmate's popularity score.
The researchers then tracked changes across the semester, looking for evidence that each student moved toward the behaviors of their best friends versus the behaviors of the popular kids in their class.
Private Currency vs. Public Market
The pattern that emerged was consistent across the sample. Best friends were the primary drivers of emotional problems, lack of emotional clarity, problem behaviors, and lower school achievement. Popular peers, by contrast, dominated outcomes that play out in front of an audience - specifically social media use and weight concerns.
Lead author Mary Page Leggett-James described the dynamic in economic terms: "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 logic behind the split is grounded in how each type of relationship functions. Friendships are built on reciprocity and intimacy. When a close friend struggles with anxiety or disengagement from school, those states can transfer through the emotional closeness of the bond. "Anxiety, disengagement from school, or acting out can spread between friends and have a snowball effect," Laursen said.
Popular peers operate differently. Status hierarchies in adolescent peer groups reward public conformity - wearing the right clothes, maintaining the right online presence, having the right body. Teens who want to be accepted by the high-status group signal that acceptance by adopting visible behaviors. They do not need to be close friends with popular students to be influenced by them; observation from a distance is enough.
What This Means for Intervention
The practical implications are substantial. Programs targeting adolescent emotional health or academic disengagement should focus on friendship dynamics, not popularity hierarchies. Attempting to break up a friendship that is reinforcing negative emotional patterns may backfire; instead, interventions that help adolescents build positive peer connections within their existing social circles are more likely to help.
Social media use and body image concerns require a different approach. "Issues tied to social media and body image require shifting status norms," said Leggett-James. "When popular students display healthier, more realistic standards, they can redefine what classmates consider normal." That finding points toward interventions that engage high-status students as change agents rather than trying to reach every individual separately.
The study was conducted in Lithuania, which raises questions about how well the findings generalize to other cultural contexts where adolescent social hierarchies may be structured differently. The semester-long follow-up period is also relatively short - it captures influence over weeks, not years. Longer-term studies would help clarify how these effects compound over the full arc of adolescence.
The research was supported by the European Social Fund and the Research Council of Lithuania. Co-authors include Rene Veenstra of the University of Groningen and Goda Kaniusonyte of Mykolas Romeris University.