  Observable social traits determine how we interact in society and remain
pervasive even in our globalized world. While a popular hypothesis states that
they may help promote cooperation, the alternative explanation that they
facilitate coordination has gained ground in recent years. Here we explore this
framework and present a model that investigates the role of ethnic markers in
coordination games. We consider fixed markers characterizing agents that use
reinforcement learning to update their strategies in the game. For a wide range
of parameters, we observe the emergence of a collective equilibrium in which
markers play an assorting role. However, if individuals are too conformists or
greedy, markers fail to shape social interactions. These results extend and
complement previous work focused on agent imitation and show that reinforcement
learning is a good candidate to explain many instances of ethnic markers.
