This article distinguishes between scarcities resulting primarily from entropic processes and those which appear to be more immediate outcomes of social, economic, and political processes. The discussion then proposes the linking of two Lasswellian propositions; Maslow's hierarchy of needs; and the cybernetic concept of motivation as “felt gap” between an actor's perception of an existing state of affairs and a preferred state. In responding to gaps emerging from changes in physical and social environments, the actor is seen as tending to alter these environments and then adjusting future behaviors in order to cope with such changes as perceived. But whereas response choice tends to be influenced by each actor's perception of capabilities, of which perceived resource availabilities (or scarcities) are an element, response outcomes are likely to be constrained by the “real” capabilities (including resource availabilities) of the actors. Over time, responses involving changes in population and technology (knowledge and skills) contribute to changes in the resource availability and other variables.