  We study how information transmission biases arise by the interplay between
the structural properties of the network and the dynamics of the information in
synthetic scale-free homophilic/heterophilic networks. We provide simple
mathematical tools to quantify these biases. Both Simple and Complex Contagion
models are insufficient to predict significant biases. In contrast, a Hybrid
Contagion model -- in which both Simple and Complex Contagion occur -- gives
rise to three different homophily-dependent biases: emissivity and receptivity
biases,and echo chambers. Simulations in an empirical network with high
homophily confirm the existence of these biases. Our results shed light into
the mechanisms that cause inequalities in the visibility of information
sources, reduced access to information, and lack of communication among
distinct groups.
