Developmental Insights into Evolving Systems: Roles of Diversity, Non-Selection, Self-Organization, Symbiosis

A developmental view of evolving systems (ecological, social, economical, organizational) is examined to clarify 1) the role of selection processes versus collective, non-selective processes, 2) the origins of diversity and its role in system performance and robustness 3) the origin of explicit subsystem interactions (cooperation/symbiosïs) that enhance individual and system performance, 4) the preconditions necessary for further evolutionary development, and 5) the effect of environmental timescales with adaptation timescales. Three sequential stages of evolving systems (based on the work of Salthe) are proposed: a fmmature stage dominated by highly decentralized, selective processes with chaotic local and global dynamics, a Mature stage dominated by non-selective, self-organizing processes with global robustness but locally chaotic dynamics, and a Senescent stage dominated by rigid interactions with global fragility. A simple model problem with many optimal and non-optimal solutions an agent solution to a maze illustrates the entire developmental history. Within the model, the agents evolve their capability from a random approach to an optimized performance by natural selection. As the agents develop improved capability, natural selection becomes rare, and an emergent collective solution is observed that is better than the performance of an average agent. As the collèctive, self-organizing structures are incorporated into individual capability within a stable environment, constraints arise in the agent's interactions, and the system loses diversity. The resulting Senescent system exhibits reduced randomness due to the rigid structures and ultimately becomes fragile. Depending on the degree environmental change, the Senescent system will either "die," or collapse under environmental stress to the Mature or Immature stage, or incorporate the constraints system-wide into a new hierarchical system. The current study adds to tise literature on developmental systems by finding: Transitions between stages are dependent on the degree of sustained environmental stability and how exclusive cooperation (e.g., symbiosis) in a subsystem can originate, and how it results in a decline in diversity. Cop yrigh ted Material I ut rod uct ion On challenge for researches in evolving systems, whether for economic, ecological, political, social or organizational systems, is a common viewpoint for both understanding the dominant processes in their models and a basis by which to compare their models to others. The current work grew out of research on how self-organizing groups can solve problems better than experts and the consequent need to understand non-selective, self-organization processesi (Johnson et al. 1998) and how it relates to natural selection (Johnson 2000). Both selective and non-selective processes are observed in real systems and have validity. Both processes increase global fitness, but by distinctly different mechanisms. But, because each originates from very different viewpoints (competitive versus non-competitive agents), can they be reconciled into a single understanding? It was from this starting point that the current study began. A detailed examination of the dynamics and properties of nonselective self-organization was done (Johnson 1998), but offered iso real insight into how this approach to global function related to selective processes. What was finally discovered was that these seemingly different approaches are representative of different stages of an evolving system (Johnson 2000). And the apparent conflict is resolved by a developmental perspective of evolution, based on the sustained work by Salthe tmAn example of non-selective self-organization is foraging in social insects (Bonabeau et al. 1999), expressing what is called "swarm" intelligence. In the absence of selection (no ants die), a foraging group can be observed to perform greater than the capability of the individual (e.g., the path to the food is shorter for the average group than the best individual). These final paths represent the collective action of many individuals solving their own path problem, in a manner that is ultimately useful to the entire population but which is never expressed as a goal at the level of the individual. Another example is path formation in humans and the method for book referral used by Amazon.com (Johnson 1998). Downloaded from http://direct.mit. edu/books/book/chapter-pdf/268150/9780262291071_cbm. pdf by guest on 12 July 2021 (1989, 1993, 1999) for ecosystems. Within this developmental view, an extension of the model problem developed for non-selective self-organization is used to illustrate the full developmental history of evolving systems. This study begins to address many questions of interest in the fields of evolutionary systems: How do groups achieve higher global functionality? How can the robustness of the system be improved? What global properties are prerequisites for greater functionality? How does the system "boot-strap" itself to a higher functionality? The approach taken is review the developmental view of evolving systems, and then propose simple model problem to illustrate the stages of the theory and the mechanisms for transitions from one stage to another. While the simple model is not rich as real systems or highly developed simulation models, its simplicity enables clear discussion of the processes characterized by the general theory. Developmental View of Systems In this section a developmental view of evolving systems is presented, a summary of the work of Salthe (1989, 1993, 1999) and its extension to a other systems, economic, political, social, and organizational (Johnson 2000). The focus, here, is on the interplay of natural selection with non-selective processes, on the role of diversity, and on the transference of global emergent properties to subsystems. While three stages are presented below, it is understood that these are just points in a continuous development. Furthermore, to simplify the presentation, the systems are assumed to be homogeneous in the progress of maturation (subcomponents are not mixed across states). More likely, systems will have multiple stages of development simultaneously, particularly as a system increases in complexity and partially independent subsystems undergo cycles of maturation and failure and become out of