With an emphasis on procedural fundamentals, the original behavior-analytic equivalence experiments and the equivalence paradigm are described briefly. A few of the subsequent developments and implications are noted, with special reference to the possible significance of the findings with respect to language and cognition. (Contains 9 figures.)

Lowenkron and colleagues (Lowenkron, 1984; 1991; 1998; 2006; Lowenkron and Colvin, 1992) describe a model that explains complex behavior using only well-established behavioral principles, concepts and terms. The model, called "joint control," is especially useful for understanding complex and delayed discriminations within a purely behavioral…