From micro to MACRO, a local interactions tale \ EMERGENCE _ STEVEN JOHNSON


human-chain-necklace-short_1377085572_4From science to sociology, the ants colony organization, the human cells communication, the great cities development, Steven Johnson trough these three case studies explores the different interactions typologies from a micro to a macro scale, in order to study the relations between local interaction and global behavior.

The author analyze first the ants life, the colony organization, in order to understand the collective intelligence of the colony system.

The ant colony is a complex and intelligent system based on a single and “stupid” one, the ant indeed, with an incredible knack for engineering and social coordination without clear roles but with a coordinated work to assure a global situation.

” They think locally and act locally, but their collective actions produce a global behavior”

The ants communication system is really simple, based on more or less 20 different signs exchanged by pheromones trough different gradients amount, a simple and restricted alphabet, which is the base for a system where macro intelligence and adaptability derive from local knowledge.

The main teaching derived from the colony system is that local interaction can lead to global-problem solving.

” Generate global behavior from local interaction ”

In this system where macro-intelligence and adaptability derive from local knowledge, he author defines five key-points which describe the ant colony:

1) More is different : critical-mass colony to make intelligent  assessments , micro-motives/macro-bahavior

2) Ignorance is useful: basic alphabet for basic information

3) Encourage random encounters: arbitrary encounters alter the macro-state of the system

4) Look for patterns in the signs: gradient smells of pheromones depend to the ants number

5) Pay attention to your neighbor: local informations can lead  to global wisdom thanks to the interactions between neighboring ants.

Each ants receives information and acts by neighbors interactions, this is the way how a single ants participates with the whole colony and the secret of the successful mechanism which move the colony itself, a bottom-up system.

The ants interaction is compared to human cell interaction, a different scale with the same characteristics.

Each cell endow the “gene -expression” the cheat sheet that enables each cell to figure out which segments of DNA to consult for its instruction.

The cells as the ants learn from its neighbors, during the creation of each human body parts each cell start to work depending on its neighbors:


” TOPO-BIOLOGY – The great beauty of embryo development, the bit that human beings find so hard to grasp is that it is a totally decentralized process. Since every cells in the body carries a complete copy of the genome, no cells need to wait for interaction from authority, every cell can acts on its own information and the signal it receive from its neighbors. ”

These two similar system are than compared with the big cities, where the authority based on the single interactions between humans, even in the city we “learn from our neighbors” but in a bigger scale, a kind of neighborhood attracts particular kind of others neighborhood, in order to create different kind of interaction based on common interests to achieve a global behavior of single habitant of the neighborhood, in this case the single behavior lead to a global one.

As Jane Jabobs says,  great cities are not like town only larger, in the city the “authority” try to determinate its growth, many times in contrast with its natural development.

The Sidewalk is the place where the neighbors interactions happen in the city, the big different between the ants and the humans interaction is that the humans think they are always in the right way, the ants do not think.

The sidewalk interaction enables city to create emergent system.

For this reason the global behavior is barely gained by the big city system, a place where local interactions are conditioned by self-centered behavior, it alters negatively the single one, a person is able to see the whole system and feels like a he is not a  part of it.

The simplicity of an ant compared with the complex colony shows the power of the simplicity and the way to learn how to create complexity from simple elements


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