Urcuioli's differential-outcomes research: Implications for our behavioral units

Our behavioral units include stimulus classes and response classes. Peter Urcuioli's differential-outcomes research implies they should extend to the third term of the three-term contingency. Classes of consequences come in several varieties (e.g., conditional reinforcers, tokens), but our vocabulary does not coherently organize them. They are differentiated not only by physical properties such as type, location, and duration but also by the schedule contingencies in which they participate. We consider units ranging from the physical and chemical sciences to those based on the particular history of life on earth. The latter include biology, sociology, linguistics, and our own behavior analysis. Scientific units are typically nested (e.g., atoms within molecules, cells within organs, organisms within species). Comparing our units with those from other taxonomies raises questions about their emergence and evolution and their shared properties across levels of nesting (e.g., species within genus, subclasses within higher order operants, phonemes within words). Emergence necessarily occurs when higher order units have functions that are not shared with their lower order constituents. These nested and multileveled behavior classes challenge single-level views, such as metaphorical accounts of behavior as a totality contained within a pie, with slices corresponding to behavior classes matched to their outcomes.