Embracing the Creativity of Stigmergy in Social Insects

One of the doyens of stigmergic computational intelligence.

There is no master architect, nor even a supervisor in these colonies. Grassé has shown that the key information required to ensure the coordination of building actions performed by insects is provided by their previously achieved work: the architecture itself. Grassé coined the term ‘stigmergy’ from the Greek words ‘stigma’, meaning ‘sting’, and ‘ergon’, meaning ‘work’, to describe this form of indirect communication. For instance, each time an ant or a termite worker executes a building action in response to a local stimulus, such as adding or removing a piece of material from the existing nest structure, it modifies the stimulus that has triggered its action. The new stimulus will then influence other specific actions from that worker, or potentially from any other workers in the colony. The stimulus itself can be a particular pattern of matter sometimes soaked with chemical signals called pheromones. Coordination is simply achieved through judiciously chosen stimulating patterns of matter. And the architecture provides enough information and constraints to ensure the coordination and regulation of building actions. The whole chain of stimuli and behavioural responses leads to an almost perfect collective construction that may give the impression that the whole colony is following a well-defined plan. Thus, individual insects do not need any representation or blueprint to build their nest. At the Centre de Recherches sur la Cognition Animale, part of the Centre National de la Recherche Scientifique (CNRS) at Université Paul Sabatier in Toulouse, we have spent the last 20 years identifying and characterising the interactions involved in the coordination of nest building in various species of wasps, ants and termites. This work has led us to identify similar building principles behind the impressive diversity of insect nest architectures and to build distributed construction models that implement these principles.

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Swarm and Fuzzy

Stigmergy gets a bit of a mention in Newsweek.

Swarms often work by “stigmergy,” a term coined by French biologist Pierre-Paul Grassé in 1959 to describe termite behavior. He defined it as “the stimulation of workers by the performance they have achieved.” It has come to mean a mark left in the environment. Think of stigmergic marks as road signs: A termite makes a ball of mud laced with pheromones (chemicals that affect behavior through smell) and puts it down. The next mud-ball-making termite that happens along smells the first, makes its own ball and adds it to the pile. Millions of balls later, a hollow mud spire stands 8 feet tall, as outlandish as the towers of Turkey’s Cappadocia region—a magnificent termite-apartment complex.

Each individual in a swarm acts seemingly at random—scientists term this “stochastic”—yet as a group a swarm is amazingly focused, coherent and logical.

Translating nature to math can be staggeringly difficult.

Check out a preview of Francis Heylighen’s paper for Ted and my forthcoming Human Stigmergy: Theoretical Developments and New Applications, Studies in Applied Philosophy, Epistemology and Rational Ethics. Springer.


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Stigmergic dimensions of online creative interaction

Extracts from Jimmy’s paper:

The web has experienced a recent proliferation of design expert communities in domains from software engineering (e.g. Sourceforge and Github) to art (DeviantArt and others). These communities have become hotbeds of creative interaction, with users posting their projects, closely interacting on new endeavors, and engaging in spirited discussion about their craft. With users in these communities constantly generating out new software, images, music and any other artifact imaginable, it is hard to deny that there is significant creative interaction happening. Members of these communities often possess widely varying degrees of proficiency, but more often than not, they have some baseline amount of talent that allows them to enter the community.

Enter Picbreeder. Picbreeder is a web-based system for collaborative interactive evolution of images. The Picbreeder applet starts by randomly generating several images, which are then mated and mutated based on the user’s selections. The user can then publish the image to the Picbreeder website where other users can download and continue the image’s evolution. Within Picbreeder, one need not have artistic talent to contribute to the community, although good taste typically helps. As in more traditional design, new innovations are typically small modifications to the existing structure, which can change the design incrementally or effect a larger shift. Even though users followed their individual interests when evolving this phylogeny, new interesting directions emerged. Many users contributed repeatedly to an evolving lineage, using the design itself to encourage and facilitate collaboration.

Successful collaborative design in Picbreeder does not require shared intentions, suggesting that effective collaboration may be emergent rather than planned from the top down. The surprising result of this emergent process is the gradual discovery by untrained users of hidden treasures within a vast uncharted space. Picbreeder also serves as a fascinating, though initially unintentional, experiment in stigmergic creativity.

The concept of stigmergy was first introduced by Pierre-Paul Grassé, a zoologist, who used it to describe the activities of the termite mound. As he described it, “(s)tigmergy manifests itself in the termite mound by the fact that the individual labour of each construction worker stimulates and guides the work of its neighbour”. The concept of stigmergy can be extended to human endeavors if one expands the notion of the mound to human venues, and replaces “construction worker” with any type of worker. If such an extension is permitted to human creative communities, this description becomes even more apt. Part of the excitement inherent in creative pursuits, whether it is visual art, music or creating open source software, is the moment when the work of a colleague “stimulates and guides” ones own work. Add that “(in) an insect society individuals work as if they were alone while their collective activities appear to be coordinated.” This description too can apply to creative communities. Points out that “(s)tudies on creativity . . . have focused on the individual, obscuring the fact that creativity is a collective affair. The ideas and inventions an individual produces build on the ideas of others (the ratchet effect).” It is very easy to focus on individual creative luminaries, while forgetting the environment and social milieu that are a large part of their creative interaction.

The results of Picbreeder not only demonstrate the truth of creativity as collaboration, but that a large component of creativity can be stigmergic. By abstracting out almost all direct communication and collaboration, and allowing users to be stimulated only by their work and the work of others, Picbreeder demonstrates the extent to which stigmergic processes can yield astounding results. This paper expounds on this point by first describing in detail what Picbreeder is and how it works (section 2). Next, the paper casts creativity in general and Picbreeder specifically into the context of memetic evolution, a model of how ideas spread, change, evolve and die out (section 3). The point is then made in section 4 that these collaborative creative environments draw a great deal of their effectiveness from stigmergic interaction facilitated through creative artifacts. In sections 5, an analysis of the Picbreeder data is described that shows, despite the fact that Picbreeder users engage in almost no direct communication, it shares numerous properties with other collaborative creative environments. Finally, some conclusions and recommendations are made in section 6.

This paper has shown that Picbreeder, an almost fully stigmergic means of collaborative creative interaction, follows many of the same patterns as other collaborative creative networks. Picbreeder demonstrates that it is possible to facilitate creative collaboration through entirely stigmergic means, and this paper explored the mechansisms that gave rise to that stigmergy. Because in other creative communities, stigmergic and non-stigmergic components of creative interaction are difficult to separate, Picbreeder provided an ideal opportunity to study this dimension. It is hoped that future studies will be able to isolate and study the contribution of stigmergic components in other creative communities.

It is also hoped that more quantitative analysis will be done on other creative communities. Academic publishing bibliometrics were used because they are plentiful and easy to access. While it is difficult to trace influence in similar way in musical or visual arts communities, developing techniques to analyze these communities is a worthwhile pursuit. This analysis may provide answers of real economic value. For instance, to answer the question, what will create a broader, more economically viable base of musical development, a U.S. style system in which music distribution is dominated by a few large gatekeepers to the music industry, or a Canadian style system which frequently uses government sponsored incentives to encourage development in musical communities?

There is a great deal of analysis left to be done and questions to be answered with respect to the dynamics of creative communities. For instance, how can Axelrod’s model of cultural diffusion (1997) explain creative influence? Also, how can Friedkin’s analysis of weak ties versus strong ones in organization flows (1982) inform the analysis of how creativity develops within and between organizations. Picbreeder is currently a “flat” community, which does not fully represent the wide variety of social creative arrangements. The addition of this dimension to analysis will hopefully yield additional insight.

Stigmergy is clearly involved in creativity. It is no accident that Silicon Valley is well known for technical innovation and Paris is a well known muse of artists. These physical locations host large collaborative and competent communities for one, but also frequently display and demonstrate the results of their interaction, to “stimulate and guide” other participants. Other creative communities might benefit by explicitly taking advantage of stigmergic concepts to improve their efficcacy. Imagine a paint studio where artists paint in a circle, with the paintings facing inward. Or a research lab where everybody’s latest work in progress is posted to a highly visible electronic board. The more we understand the role of stigmergy in creativity, the better we can shape and guide the process. Ultimately, every creative discipline, along with humanity itself, will be the beneficiaries of this advancement.

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Stigmergy in human practice: Coordination in construction work

Some excerpts from Lars’ paper.

When the concept of stigmergy was first introduced in 1959 by the French entomologist Pierre-Paul Grassé (1959), an important step towards understanding the coordination of collective activities in social insects was made. Today, the concept of stigmergy is well established within the field of entomology (Theraulaz and Bonabeau, 1999). Turning from the study of insect behaviour to the study of human practice we find the concept of stigmergy to be less well established. However, criteria for applying the concept of stigmergy to the study of human practice are in fact readily emerging and a series of interesting and illuminating studies of stigmergy in a human context has been published (e.g. Christensen, 2008; Marsh & Onof, 2008; Ricci et al., 2007; Susi & Ziemke, 2001; Tummolini & Castelfrananchi, 2007; Parunak, 2006). This paper aims to contribute to this body of literature. Building on Grassé (1959), we will argue that that a coordinative effect can occur when human individuals act on the physical traces of work accomplished previously by others. That is, we will say that actors may coordinate and integrate their cooperative efforts by acting directly on the physical traces of work previously accomplished by others and that signs left or modifications made by individuals on artifacts may, given an appropriate context of practice, become meaningful to others and in turn inspire new actions on artifacts. This is how stigmergy may unfold in a human context. However, in connection to the study of stigmergy in a human context we need to ask a fundamental question before we “get ahead of ourselves.” The question is this: Does the concept of stigmergy add anything to our ability to account for the coordination of cooperative work in a human context? After all, stigmergy is a concept of coordination (Theraulaz and Bonabeau, 1999) and if we are to apply it to the study of human practice we have to ensure that it is not redundant in this context. That is, we have to make sure that there are no other concepts of coordination already having the analytical role that we are casting for the concept of stigmergy. This work has not been done so far (see related work section), and we shall address this challenge here. We shall proceed in the following manner. First we shall discuss related work. Secondly, we shall establish the nature of the concept of stigmergy in the study of human practice. Third, we shall compare the concept of stigmergy to three well-established concept of coordination in order to satisfy ourselves that stigmergy is not interchangeable with them. Fourth, we shall employ the concept of stigmergy in a study of construction work in order to explore the analytical utility of the concept in a human context. Finally, a conclusion and some perspectives will be offered.

In construction work, as in building design (Christensen, 2007; 2008), interdependent tasks may be partly integrated by virtue of individuals paying heed to the material evidence of work previously accomplished by others while performing their own tasks. Cooperative construction work tasks may be integrated through practices of stigmergy. As a case in point we shall consider the integration of cooperative work tasks pertaining to the construction of interior walls in a large building project. In the interior construction stage of a large building project a considerable number of partition walls are constructed. Partition walls are what divide the building into for instance units of office space. The construction of these walls is a cooperative work process involving a number of different trades such as carpenters, electricians and painters (see figure 2). The first and second frame shows the result of the carpenter’s initial efforts. The third frame, including insert, shows the work of the electrician in progress. Finally, the fourth frame depicts the closed wall ready for painting. The initial parts of a partition wall is constructed by a carpenter in the form of a frame made of light weight steel grinders fitted with plasterboards on the one side. At a later point in time, another actor, namely, an electrician will arrive and pay heed to the work carried out and seek to align the wiring of the electrical circuits with it. That is, the electrician will drill holes in the plasterboard to accommodate the electrical instillations and he or she will pull electrical cables through little holes in the vertical steel grinders of the frame and connect them to the electrical system as a whole. When the electrician is done and has left the scene, the carpenter returns to close the wall i.e. clad the second side of the wall in plasterboards in accordance with the previous work done. That is, the carpenter must take notice of the work previously performed by himself and the electrician as he seeks to put up the second round of plasterboards. Subsequently, the painter shows up to paint what the others have erected. At this point the wall in-the-making will have been worked on to consist of a steel frame, plasterboards on the first side, electrical instillations inside, and plasterboards on the second side. Finding the wall in this state the painter paints the wall with several coats of paint. In this manner the work ensemble including carpenter, electrician and painter all make distinct contributions towards the construction of the wall in accordance with their respective areas of expertise. We could say that the individual actor creates and changes the form of the wall in-the-making, not for the purpose of conveying a message, but simply as part of performing their individually allotted tasks, in turn another actor pays heed to and acts upon the material evidence of the work of others. This is partly how the cooperative work tasks pertaining to the construction of partition walls are integrated through practice of stigmergy. Perhaps to allow for full appreciation of the importance of this mode of coordination in building construction work, it would prudent to recall that no formal construct (e.g. architectural plan) exhaustively stipulates a concrete practice. Plans are underspecified with respect to that which is represented (Suchman, 1987), and architectural plans for the construction of for example partition walls are no exception. The actors have to “fill in the blanks” for themselves, so to speak, and acting on the evidence of work previously accomplished by others may be said to be one way of doing this. Furthermore, please bear in mind that architectural plans for specific building parts such as walls are not assembly manuals like those that come with for example IKEA furniture, rather architectural plans represent mainly how parts of the building it are supposed to look in the final state. Consequently, the assembly of for example partition walls is not covered in architectural plans. In addition, the pace of contemporary construction work is such that as soon as one actor (e. g. carpenter) has completed a task, time does not allow for much standing around and talking to the next actor (e. g. electrician) even though their tasks are interdependent and there are numerous details that need to be integrated. Of course articulation work through talk on the building site or in weekly coordination meetings may contribute to the integration of cooperative construction work tasks, but so may acting on the material evidence of work previously accomplished. The point is that in addition to various kinds of articulation work in meetings and with and without coordinative artifacts such as time schedules, cooperative construction work is coordinated by virtue of actors paying heed to the material evidence of work previously accomplished by others while performing their own tasks. At this juncture we may ask if the physical “evidence” of work may be promoted by the way in which the work is performed making it more straightforward for others to act on in practice of stigmergy? With reference to our case above, we may say that an electrician could for example install the electrical wiring and let a cable hang conspicuously visible in order to make the carpenter pay heed to it and afford it the required space as the wall is closed with the second layer of plasterboards (if the cables are completely hidden to the carpenters view he or she may accidentally put a nail through it with the nail gun as the second layer of plasterboards are mounted on the frame of the wall). This raises an interesting point: coordination through the material field of work may also be a matter of being mindful of the work that is to be performed by others looking forward in time, rather than only a matter of paying heed to work previously accomplished by others. At this point we may remind ourselves “the economy of logic […] dictates that no more logic is mobilized than is required by the needs of practice” (Bourdieu, 1992, p. 145). Following Bourdieu, we may say that the individual actors will engage in no more physical and cognitive effort than is practically necessary. That is, unless an actor has practical reasons for considering the situation from the perspective of others such as for example subsequent actors that may follow in practices of stigmergy, he or she will retain his or her own perspective and just carry out the work without though for the perspectives of others. Note that it is of course an empirical matter, something that differs from case to case, exactly how this plays out in practice. It is important to note that stigmergy, as a coordinative practice, is in not dependant on such forward looking mindfulness although it may be part of the larger set of practices. In sum, in construction work, cooperative work tasks are (partly) integrated through practices of stigmergy.

The concept of stigmergy was not originally developed in order to describe human practice, rather it was developed within the field of entomology i. e. the study of social insects. This study has raised and addressed a question central to any attempt to introduce the concept of stigmergy to the study of human practice: Does the concept of stigmergy add anything to our ability to account for the coordination of human cooperative work or is it simply interchangeable to already existing concepts? We have argued that it does add a new analytical perspective. Initially we suggested that in the context of human practice it is fruitful to understand stigmergy as a “heed” concept. That is, stigmergy refers to the phenomenon that distributed cooperative work tasks may be partly integrated by virtue of individuals paying heed to the material evidence of work previously accomplished by others while performing their own tasks. Based on this understanding of the concept of stigmergy in the context of human practice we explicitly compared and delimited the concept in relation to well-established concept describing human coordinative practices. We found that it differs from these concepts. We found that the concept of stigmergy is not interchangeable to well-established concepts of coordination such as articulation work, awareness and feedthrough. Finally, we explored the potential of the concept of stigmergy in an empirical study of coordinative practice in construction work in order to further investigate the utility of the notion of stigmergy as an analytical tool in the context of human practice. In regard to perspectives for further research, we may note that the three concepts of stigmergy, articulation work and awareness could amount to a trinity in the analytical toolbox for the description and analysis of the coordination of cooperative work – each concept pertaining to a unique yet interconnected mode of coordination of cooperative work.