Explanations for historical chain shifts tend towards the teleological using abstract ideas like balance and equilibrium as the organizing principles of a languages sounds. This paper investigates whether there are more basic phonetic principles governing the behavior of sound categories with respect to one another. Using a computational simulation of agents communicating with each other, I show that vowel chain shifts fall out naturally from an exemplar-based model of sounds. This suggests that no overarching teleological mechanisms are required to account for chain shifts and that the self-organizing behavior of exemplar-based categories provides an adequate explanation.