Swarm theory

Call it the wisdom of crowds, or crowdsourcing, or mass collaboration. How collectively, stupid units with only a few rules can display intelligent behavior. Each individual unit collects only local information from a neighbor and never sees the big picture, but impressive results are achieved.
We see such self-organization in resource collection of ants and bees, and in the movement of fish schools and bird flocks. There are applications to human group behavior, too. To my knowledge, it is the basis of AI. I mean, really, how intelligent is an individual neuron, all by itself?