Communication systems reliably self-organize in populations of interacting agents under certain conditions. The various fields which model this - game theory, cognitive science and evolutionary linguistics - make different assumptions about the learning and behavioral processes which are responsible. We created an exemplar-based framework to directly compare these approaches by reproducing previously published models. Results show that a number of mechanisms are shared by the systems which can construct optimal communication. Three general factors are then proposed to underlie any self-organizing learned system.