ABSTRACT
This chapter deals with a mode of performance variability that subsumes modes addressed in all other chapters in this text, namely variability in human work performance. Human work behavior defines the human condition (T.J. Smith, 2001). In a feedback fashion, it has guided the course and pace of human evolution, as well as the emergence and elaboration of human civilization (Chapter 11). It forms the basis of the development and functioning of all patterns of human social, technological, organizational, institutional, economic, governmental, and nation-state designs. The central concern of the field of HF/E science is human work performance-Murrell first proposed the term ergonomics to refer to the natural laws (nomos) of work (erg) (Konz, 1995, p. 12). In the HF/E community, broad agreement has emerged that such laws refer to design factors, conditions, and strategies that accommodate the capabilities and limitations of the worker.
