# Becoming as Open‐Minded and Organized as My Classmates? Peer Effects on Self‐Reported Personality Trait Development in the Classroom

## TL;DR

This study explores how classmates' personalities influence adolescents' personality development, finding that classroom openness and conscientiousness do not support individual growth in these traits.

## Contribution

The study provides empirical evidence on peer effects in personality development using multilevel structural equation modeling with German adolescents.

## Key findings

- Individual personality levels remained stable over time.
- Higher classroom openness was linked to lower individual openness at a later measurement.
- Classroom-level personality composition showed no systematic positive effects on individual trait development.

## Abstract

How does a student's personality development relate to the personality of their classmates? The school class builds a pertinent comparison group during adolescence that has been identified as a critical factor in students' development of abilities and self‐perceptions. This study empirically tests the impact of classroom personality composition on changes in adolescents' Big Five personality traits. We hypothesized positive associations between class‐level openness and conscientiousness and the individual development of these traits given their role in academic performance.

To test these hypotheses and explore additional composition effects, we employed three approaches of multilevel structural equation modeling on two large longitudinal samples of German adolescents (N
1 = 5470; N
2 = 788).

Our analyses yielded two principal findings: First, individual personality levels remained highly stable across different time periods. Second, contrary to our hypotheses, baseline class‐level openness and conscientiousness were not positively linked to individual personality development. Instead, there were some indications that higher class‐level openness was negatively linked to individual openness to experiences at the second measurement point.

We discuss the absence of systematic composition effects at the classroom level and consider methodological challenges in investigating these effects.