The value of human work, even when it is primarily physical, arises from unique cognitive capabilities. This article samples a broadly distributed research base regarding influences of the physical environment on human cognition. The presentation draws primarily on studies conducted within the context of dynamic physical domains of work, to address controls and information sources for enabling human intervention, and related reasoning and planning. Several examples illustrate the role of the environment as a source of information and as an influence on the sequencing of work activity. Life support is discussed both as an instance of a dynamic physical system and for its potential to preclude direct engagement with the environment, with predictable cognitive consequences.