Joint control and the generalization of selection-based verbal behavior.

Although the acquisition of selection-based verbal behavior can be ascribed to the acquisition of a conditional discrimination, such an account cannot explain any generalization of the behavior to novel verbal stimuli. The problem is that printed and spoken words and phrases do not vary on continuous dimensions that would support stimulus generalization. Both conceptual analysis and empirical evidence suggest that an alternate form of stimulus control, joint control, can more readily account for acquisition and generalization of these performances. The fact that joint control depends on topography-based behavior implies that generalized selection-based behavior is not an alternative to topography-based behavior but depends on its prior development.