Quantitative order in B. F. Skinner's early research program, 1928-1931.

The purpose of this article is to provide a coherent story of Skinner's graduate-school (1928-1931) research projects, adding to Skinner's own accounts a different emphasis and a number of interesting details. The story is guided by the proposal that a search for quantitative order was the "unifying force" amid the variety of apparatus changes and shifts of research topic in Skinner's early development as a researcher. Archival laboratory-research records from several apparatuses which Skinner constructed between 1928 and 1931 (1) indicate that his research program was more complicated than he has implied; (2) show that he worked on three interdependent lines of investigation simultaneously; (3) suggest that change or abandonment of an apparatus or a project was markedly affected by his success (and failure) in his primary objective, which was to find quantitative orderliness in measured behavior. Frequent apparatus change in the period of 1928 to 1930 ceased when he obtained quantitative orderliness in the panel-press and lever-box preparations. In the examination of archival records, questions about the enterprise of biographical understanding are considered.