Abstract. This talk will describe work in two areas: designing systems of independent agents to achieve a desired collective result, and evolutionary modeling showing a long-term selective advantage for individual mortality. In both cases, the key to the result is behavior shaped by persistent environmental state.
(1) Termites build huge, complex structures through the collective actions of millions of independent agents. These natural systems inspire the research area of collective construction, whose goal is to develop autonomous multi-robot systems that build large-scale structures according to user specifications. I will discuss the design and realization of a system of climbing robots that flexibly build requested structures using specialized materials. Robots act independently under decentralized control, using local information, onboard sensing, and implicit coordination through manipulation of a shared environment. A user can specify a target structure using a high-level representation, and robots follow simple rules that guarantee the correct completion of that structure.
(2) The standard evolutionary understanding of aging and mortality explains both as unfortunate side effects of evolution, opposed by selection but impossible to eliminate, and holds that natural selection cannot directly favor shorter lifespan or programmed death for an organism. However, this theory is based on an implicit assumption of spatial averaging. When spatial distributions of populations are taken into account, a variety of self-limiting behaviors robustly evolve, maintained through long-term environmental feedback. We found that self-limited lifespan is reliably favored in spatial systems, providing an additional mechanism contributing to senescent effects, and helping to account for classically anomalous empirical data on natural lifespans and intrinsic mortality.