On the role of morphology and materials in adaptive behavior

Even though many authors use embodied systems for their research on adaptive behavior, only few deal explicitly with shape or morphology. The adaptive potential is seen at the level of the control architecture in artificial systems or the neural substrate in natural systems. Moreover, discussion of materials is almost entirely absent. On closer inspection, it turns out that control depends crucially on morphology (shape of body and motor system, sensor shape and placement on agent) and on materials. We introduce the concept of “ecological balance” which means that, given a particular task environment, there is a harmonious relationship between morphology, materials, and control. It is argued that including morphology and materials into our considerations not only leads to a new understanding of adaptive behavior but also to potentially better designs of artifacts. Using a series of case studies from natural and artificial systems, the concept of “ecological balance” is illustrated and it is shown how it can be investigated using a synthetic methodology. For example, it is shown that often morphology and materials can be traded for computation: having the right morphology and the right materials may significantly simplify control. The final section summarizes the results and critically evaluates the current state of this research. Key phrases: relation between materials, morphology and control; ecological balance.