These elements are considered from an ecological perspective. The theory argues, essentially, that variation occurs in an environment and/or a population within it (such as increased competition for resources); that the environment and/or other populations respond to this variation by selecting for certain behaviors (such as effective use of the information); and that these behaviors are then retained (successful users of information "survive"). Ecological studies are thus interested in the development of relations, but also in the surrounding environment, which consists of material, informational, and technological constraints. The following discussion focuses primarily on informational and technological constraints, at the individual, group or organizational and societal levels of analysis.