Emergence of two-phase behavior in markets through interaction and   learning in agents with bounded rationality
  Phenomena which involves collective choice of many agents who are interacting with each other and choosing one of several alternatives, based on the limited information available to them, frequently show switching between two distinct phases characterized by a bimodal and an unimodal distribution respectively. Examples include financial markets, movie popularity and electoral behavior. Here we present a model for this biphasic behavior and argue that it arises from interactions in a local neighborhood and adaptation & learning based on information about the effectiveness of past choices. 
Sitabhra Sinha and S. Raghavendra