Stigmergy

(The Information Systems Foundations: Constructing and Criticising Workshop at the ANU, 16-17 July 2004 + stigmergy)

The term “stigmergy” was originally proposed in 1959 by the French scientist, Pierre-Paul Grasse, in his study of social insects, and more specifically, while observing termite building behaviour (1959).

For example, ants exchange information by laying down pheromones on their way back to the nest when they have found food. In that way, they collectively develop a complex network of trails, connecting the nest in the most efficient way to the different food sources [= navigation].

Other eusocial creatures, such as termites, use pheromones to build their complex nests by following a simple decentralized rule set. Each insect scoops up a mudball or similar material from its environment, invests the ball with pheromones, and deposits it on the ground. Termites are attracted to their nestmates’ pheromones and are therefore more likely to drop their own mudballs near their neighbours’. Over time, this leads to the construction of pillars, arches, tunnels and chambers [= construction].

Grasse defines stigmergy:

the coordination of tasks and the regulation of constructions does not depend directly on the workers, but on the constructions themselves. The worker does not direct his [sic] work, but is guided by it. It is to this special form of stimulation that we give the name Stigmergy (stigma, wound from a pointed object[, i.e. mark or sign]; ergon, work, product of labour = stimulating product of labor). (In [and tr.] Holland and Melhuish [1999] 2)

The term stigmergy describes the influence that information derived from the local environmental effects of the activities of previous individuals has on the current behaviour of individuals [= feedback “in action”].

Camazine et al. (2001) refer to stigmergy as the process of information gathering from work in progress from the environmental effects of the work rather than directly from fellow workers. As they describe it, in continuing with the social insect analogy:

instead of coordination through direct communication among nestmates, each individual . . . adjust[s] its building behaviour to fit with that of its nestmates through the medium of the work in progress. (24)

Stigmergy is the way a system organises itself through the collective behaviour of individuals within its environment. As the individual moves through the environment, it gathers or emits information, or interacts with the environment, i.e. leaving traces, i.e. cues, in work or otherwise, that stimulate the work of other individuals, who do the same in turn. Over time, a pattern of construction emerges out of this coordinated action. [It is also known as swarm intelligence.] (The theory does not explain how or when construction ends or how errors made during construction are dealt with.)

Stigmergy can explain the transfer of information among individuals, when each individual needs to determine what to do and where a direct line of information from one individual to another individual does not exist; transfer instead occurs through

  1. the stimulus of previous individuals’ information [sematectonic (A – T – ?): from sema (sign, token) and tecton (craftsman, builder) (Wilson 186)] and
  2. construction activities embedded in the environment [stigmergic (A – T – A): acc. to Wilson, stigmergy is a subset of sematectonic behaviour].

Figure 9.3, “Stigmergy information flow” summarises this process. Here the work previously accomplished by one or more individuals is imprinted in the environment as a cue/stimulus for other individuals.

Figure 9.3. Stigmergy information flow.

Note that stigmergy is not restricted to eusocial creatures, or even to physical systems. On the internet there are many emergent phenomena that arise from users interacting only by modifying local parts of their shared virtual environment.

Such self-organised ucs intelligence or collaboration = deep thinking (generated unawares), like deep learning (delivered unawares). Can it be mobilised? Perhaps. It can perhaps be “fed back.” The teacher activates the feedback process by “imprint[ing] . . . information via cues and/or stimulus” on the environment.

See Pierre-Paul Grasse, “La reconstruction du nid et les coordinations interindividuelles chez bellicositermes natalensis et cubitermes sp. La theorie de la stigmergie: essai d’interpretation du comportament des termites constructeurs,” Insects Sociaux 6 (1959): 41-80.

E.O. Wilson, Sociobiology: The New Synthesis (1975; Cambridge, MA: Harvard UP, 2000) 186.

Also: distributed cognition, extended mind, situated cognition.

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