Friendship Network Evolution and Health Behavior of University Students

The change rate of friendship network increased in the early stage, and kept steady in later stages. The reciprocity and transitive triplets played important role in the maintenance or friendship. During initial stage, the behaviors of exercise, breakfast-eating, internet and night snack were important.

While in later stage, smoking and drinking behavior became important. The conclusion is that the characteristics of behaviors as visible or invisible would be determined by the social norm. In the early stage, the behaviors accepted by social norm would be as visible and determine change in network, whereas the behaviors not accepted by social norm would be invisible.

And the invisible behaviors would become visible in the later stage.