Environment structure and adaptive behavior from the ground up

We describe a framework for exploring the evolution of adaptive behaviors in response to different physical environment structures. We focus here on the evolving behavior-generating mechanisms of individual creatures, and briefly mention some approaches to characterizing different environments in which various behaviors may prove adaptive. The environments are described initially as simple two-dimensional grids containing food arranged in some layout. The creatures in these worlds can have evolved sensors, internal states, and actions and action-triggering conditions. By allowing all three of these components to evolve, rather than prespecifying any of them, we can explore a wide range of behavior types, including “blind” and memoryless behaviors. Our system is simple and well-defined enough to allow complete specification of the range of possible actiontypes (including moving, eating, and reproducing) and their effects on the energy levels of the creature and the environment (the bioenergetics of the world). Useful and meaningful ways of characterizing the structures of environments in which different behaviors will emerge remain to be developed.