Statistical mechanics of ants

I like to say that the IT model looks at human behavior as so complex that it looks like randomness at the micro level. Basically, there is so much going on that statistical mechanics kicks in (most of the time [1]) and the macro behavior is well-described by a gas or fluid.

In this video (article here) from Georgia Tech, the behavior of individual ants is very complicated, but at the macro level the ants behave as a fluid (or more accurately a state that has properties of solids and fluids):

The decision process in each tiny (but still too complex to model with a computer!) ant brain of what force level to let go and "play dead", to stick together or not, is aggregated into a single number: a viscosity coefficient.
Footnotes:
[1] Recessions and other mass coordination events are the exception, but most of the time, the economy is not in a recession.