  This paper proposes a general model for synchronized crowding behavior. An
order parameter is introduced to quantify the level of synchronization which is
shown a function of percentage of agents in reactive state. Further,
synchronization is shown to be driven by the most active agents with the
highest volatility. A tipping point is identified when crowd becomes
self-amplifying and unstable. By applying this model, financial bubbles, market
momentum and volatility patterns are simulated.
