Evolution of social networks and body mass index for adolescence

Abstract

We hypothesized that social norm for BMI has effect on the evolution of social networks. The goal of the present study is to analyze the evolution of friendship network and body mass index (BMI) for adolescent in 3 different classes-boys’ and girls’ class, boys’ class, and girls’ class. A network survey was carried out in classrooms of high schools. The participants came from 3 classes. Sociometric data were collected by having each student nominate up to 16 intimate classmates. Panel data was collected 7 times across 2 semesters from Sep. 2008 to Jun. 2009. The program SIENA was applied to estimate the models for the evolution of social networks and BMI. The result showed that BMI has effect on girls’ class, but not boys’. In conclusion, the different composition of gender in a class will construct social norm about BMI and exerts different effect on network evolution. It is helpful for intervention plan focused on norms.