Topography-based and selection-based verbal behavior: A further comparison.

Michael (1985) identified two types of verbal behavior, topography-based (e.g., speaking or using sign language) and selection-based (e.g., using a symbol board). Sundberg and Sundberg (1990) and Wraikat (1990) compared these systems in terms of the ease of learning object naming (tact) and giving the correct sign or pointing to the correct symbol on hearing the object name (intraverbal). Sundberg and Sundberg (1990) also compared them for the spontaneous development of a new relation, identifying the object when hearing its name (stimulus class formation or equivalence). The results of both studies favored the topography-based system, but in each case some subjects were not verbally skillful enough to learn either system and some learned both too easily to permit a useful comparison. The current study replicated the two previous ones by teaching the same two verbal relations and testing for the emergence of new relations, but adjusted the task to the subject's level of functioning during the experiment. This was accomplished by varying the number of object relations being learned, and by interspersing already learned tasks with the training of new tasks. As with the earlier studies, topography-based verbal behavior was easier to learn, and led to more new stimulus-class relations than selection-based verbal behavior. These data confirm the relevant theoretical analysis, and have practical implications for a change in current language training practices.