Formation of homophily in academic performance: students prefer to change their friends rather than performance

TL;DR

This study reveals that in academic settings, students tend to reconfigure their friendships based on performance levels rather than changing their grades to match their peers, highlighting a selection-driven homophily process.

Contribution

The paper provides empirical evidence that academic homophily results from social selection rather than socialization, using detailed longitudinal data and a simple dynamic model.

Findings

Students reorganize friendships according to performance levels.

No evidence of students improving grades due to peer influence.

Homophily is driven by network reshaping, not grade adaptation.

Abstract

Homophily, the tendency of individuals to associate with others who share similar traits, has been identified as a major driving force in the formation and evolution of social ties. In many cases, it is not clear if homophily is the result of a socialization process, where individuals change their traits according to the dominance of that trait in their local social networks, or if it results from a selection process, in which individuals reshape their social networks so that their traits match those in the new environment. Here we demonstrate the detailed temporal formation of strong homophily in academic achievements of high school and university students. We analyze a unique dataset that contains information about the detailed time evolution of a friendship network of 6,000 students across 42 months. Combining the evolving social network data with the time series of the academic performance (GPA) of individual students, we show that academic homophily is a result of selection: students prefer to gradually reorganize their social networks according to their performance levels, rather than adapting their performance to the level of their local group. We find no signs for a pull effect, where a social environment of good performers motivates bad students to improve their performance. We are able to understand the underlying dynamics of grades and networks with a simple model. The lack of a social pull effect in classical educational settings could have important implications for the understanding of the observed persistence of segregation, inequality and social immobility in societies.