-by Deborah Gordon (Jun 21, 2012)
Because most of the dynamic systems that we design, from machines to governments, are based on hierarchical control, it is difficult to imagine a system in which the parts use only local information and the whole thing directs itself. To explain how biological systems operate without central control —embryos, brains and social insect colonies are familiar examples— we often fall back on metaphors from our own products, such as blueprints and programmes. But these metaphors don’t correspond to the way a living system works, with parts linked in regulatory networks that respond to environment and context. Recently, ideas about complexity, self-organization, and emergence — when the whole is greater than the sum of its parts — have come into fashion as alternatives for metaphors of control. But such explanations offer only smoke and mirrors, functioning merely to provide names for what we can’t explain. [...]
A flock of birds turning in the sky is doing something people don’t know what to do [yet]: moving together, beautifully, without a leader or choreographer. It’s a spectacular version of the collective behavior that goes on everywhere, in groups of animals and among cells within our bodies. Each bird responds to its neighbors, and the whole flock turns. Birds interact by watching each other. Each anchovy in the school responds to the currents made by neighboring fish, and the school shuts away from a shark, or splits around an obstacle, to form again on the other side. Termite colonies build enormous mounds help up by a system of arches. An arch is built without a plan: two groups of workers each build a pillar, then pile soil on top of each pillar, leaning towards the smell of their nest mates, so that the two pillars bend and meet to form an arch. On a smaller scale, the pattern of neurons firing off and on allows your brain to think, and the response of cells to neighboring ones leads embryos to develop muscle and bone out of a cluster of identical cells.
I study ant colonies and how they get things done without any central control. The contacts among ants are messages without content. What matters is merely the fact that certain ants meet. They don’t tell each other anything. The pattern of interactions is the message. What each ant does depends on the rate at which it meets other ants. The rate of encounter of each ant experiences with ants performing a certain task depends on how many ants are doing that task, and how quickly they get it done. Changing conditions change the encounter rate, and this create feedback. In this way the colony adjusts to current conditions.
Life in all its forms is messy, surprising and complicated. It’s difficult to imagine how any social group could be organized without any hierarchy. We are used to hierarchy as the principle that organizes human institutions. Think of companies, armies, governments, orchestras, schools, and clubs—without any person directing another, or having more power than another. Although we are so accustomed to hierarchy that we think of it as necessary, it is rare in Nature. Rather than look for perfect efficiency, or for another example of the same process observed elsewhere, we should ask how each system manages to work well enough, most of the time, that embryos become recognizable organisms, brains learn and remember, and ants cover the Planet.
–Deborah M. Gordon in Control Without Hierarchy, NATURE, March, 2007.