The concept of stigmergy was introduced by the French entomologist Pierre-Paul Grassé to describe a mechanism of coordination used by insects. The principle is that work performed by an agent leaves a trace in the environment that stimulates the performance of subsequent work—by the same or other agents. This mediation via the environment ensures that tasks are executed in the right order, without any need for planning, control, or direct interaction between the agents. The notion of stigmergy allowed Grassé to solve the “coordination paradox”, i.e. the question of how insects of very limited intelligence, without apparent communication, manage to collaboratively tackle complex projects, such as building a nest.
One of these insect specialists, Jean-Louis Deneubourg, was also a member of the “Brussels School” of complex systems, headed by the late Nobel Prize in chemistry, Ilya Prigogine. In this interdisciplinary environment, it became clear that stigmergy was a prime example of spontaneous ordering or self-organization, and as such potentially applicable to complex systems other than insect societies. With the advent of the agent-based paradigm in computer simulation, insect societies were conceptualized as swarms of simple agents that are able to perform complex tasks using various forms of self-organization, and especially stigmergy. The general ability to tackle complex problems exhibited by such self-organizing multi-agent collectives became known as swarm intelligence.
