Bubble Effect Induced by Recommendation Systems in a Simple Social Media Model

We investigate the influence of a recommendation system on the formation of communities in a simulated social media system. When the recommendation system is initialized with a limited number of random posts, and there is strong selection of correlated users, and therefore communities, not present when examining the internal factors of participating people, arise. This happens even when people are immutable, but are exposed only to messages coming from people that are correlated to them, according to past messages. When people are let free to evolve, reducing their cognitive dissonance, true isolated communities appear, causing the filter bubble effect.