Dependence of Adaptability on Environmental Structure in a Simple Evolutionary Model

This paper concerns the relationship between the detectable and useful structure in an environment and the degree to which a population can adapt to that environment We ex plore the hypothesis that adaptability will depend unimodally on environmental variety and we measure this component of environmental structure using the information theoretic un certainty Shannon entropy of detectable environmental conditions We de ne adaptability as the degree to which a certain kind of population successfully adapts to a certain kind of environment and we measure adaptability by comparing a population s size to the size of a non adapting but otherwise comparable population in the same environment We study the relationship between adaptability and environmental structure in an evolving arti cial population of sensorimotor agents that live reproduce and die in a variety of environments We nd that adaptability does not show a unimodal dependence on environmental variety alone although there is justi cation for preserving our unimodal hypothesis if we consider other aspects of environmental structure In particular adaptability depends not just on how much structural information is detectable in the environment but also on how unambiguous and valuable this information is i e whether the information accurately signals a di er ence that makes a di erence How best to measure and integrate these other components of environmental structure remains unresolved