HOW THE "INVISIBLE HAND" MAY WORK

From HuffPo, I found a link to this interesting article about intelligent group behavior based upon extremely simply individual behavior: Swarm Theory. This seems to be a theory of how something like Adam Smith's "invisible hand" can appear to function in various contexts:

Where this intelligence comes from raises a fundamental question in nature: How do the simple actions of individuals add up to the complex behavior of a group? How do hundreds of honeybees make a critical decision about their hive if many of them disagree? What enables a school of herring to coordinate its movements so precisely it can change direction in a flash, like a single, silvery organism?