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  • Writer's pictureKaylyn Kim

The Affect of Peer Influence on Adolescents

Updated: Mar 23

Written in January 2024 by Kaylyn Kim

This essay strives to answer the question, "How and Why Does Peer Influence Affect Adolescents?"

Peer influence “…involves changing one’s behavior to meet the perceived expectations of others”. This phenomenon primarily affects adolescents—“the age between puberty…and the age at which you [they] attain a stable, independent role in society”—because of structural metamorphoses in the brain. Understanding why peer influence occurs and analyzing its effect on adolescents can help juvenile facilities create environments where adolescents can learn from their mistakes and grow. 

Recently, the University of Chicago Press conducted a study where adolescents were randomly assigned into peer groups to study together for an exam. The organization initially measured a student’s work ethic by four categories: how determined they were in the face of challenges, how confident they were of their academic skills, how anxious they were about their future success, and how prone they were to “engage in risky behavior”. Results of the experiment showed how studying with more persistent peers raised one’s overall GPA, whereas studying with risk-prone students had the opposite effect. 

Yet, the extent of peer influence lies far beyond how adolescents perform at school. To elaborate, Dr. Laurence Steinberg from Temple University created the “Spotlight Game”—an online game where an adolescent within a Magnetic Resonance Imaging (MRI) scanner must decide to stop or go at a yellow-light intersection. The first time, the participant plays, assuming no one is watching them. The second time, however, the adolescent hears their friends’ voices through a speaker and is notified that their friends are observing them. Adolescents had more car accidents in the virtual game when informed of their peers' presence.

To explain this phenomenon, Sarah-Jayne Blakemore, a Psychology and Cognitive Neuroscience professor at the University of Cambridge, studied how the social brain—“the network of brain regions that are involved in understanding other people”—undergoes a rapid transformation during adolescence. First, the limbic system—the brain region that triggers human reward systems—is sensitive in adolescents because there is an increase in chemicals that heighten pleasure from risk-taking. In other words, adolescent brains directly view social acceptance from their peers as a reward for their risky behavior. Furthermore, the prefrontal cortex—the brain region that affects “… judgment, impulse control, and planning”—develops much later than the limbic system, explaining why adolescents rely more on emotions than reasoning. 

Consequently, this raises the dilemma of how adolescents should be punished for crimes. In the United States, two-thirds of juvenile facilities are correctional-style, meaning that adolescent criminals are confined from society when they commit a crime. Yet, since adolescent behavior changes with different peer influences, Michael Corriero—the founder of the New York Center for Juvenile Justice—advises that the primary goal when addressing juvenile crimes “…should be that of rehabilitation and not a punitive one”. 

As explored in this essay, peers have an increasing presence in one’s habits and decision-making skills during adolescence because of their developing limbic system and prefrontal cortex. While there is still debate on how to address juvenile crimes, examining the effect of peer influence on adolescents can eventually design a world that leads adolescents one step closer to adulthood.



Brains on Trial with Alan Alda: Peer Influence and Adolescent Behavior [online video], Brains on Trial, 26 September 2013,, (Last Accessed: 30 December 2023)

Burns A. and Darling N., “Peer Pressure Is NOT Peer Influence”, The Education Digest, 82:1 (2002): 4-6

Department of Psychology, “Professor Sarah-Jayne Blakemore”, University of Cambridge, [ Last Accessed: 30 December 2023]

Golsteyn B. H. H., Non A., and Zölitz U., “The Impact of Peer Personality on Academic Achievement”, Journal of Political Economy, 129:4 (2021): 1052–1099

How friendship affects your brain – Shannon Odell [online video], TED-Ed, 16 September 2022,, (Last Accessed: 30 December 2023)

Jones T., “Brain Development During Adolescence”, Lumen Learning, [ Last Accessed: 30 December 2023]

Sarah-Jayne Blakemore: The mysterious workings of the adolescent brain [online video], 18 September 2012,, (Last Accessed: 30 December 2023) 

The juvenile system is broken. Here’s what actually works. [online video], PBS NewsHour, 29 October 2021,, (Last Accessed: 30 December 2023). 

The Neuroscience of the Teenage Brain—with Sarah-Jayne Blakemore [online video], The Royal Institution, 22 August 2018,, (Last Accessed: 30 December 2023).

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