Date of Award
Doctor of Philosophy
Michael (1985) distinguished between selection-based (SB) and topography-based (TB) verbal behavior. Several studies comparing the ease of learning the two systems have shown conflicting results. The data indicate that subjects with fewer lower verbal skills have done better with TB systems (subjects with developmental disabilities in studies by Hodges & Schwethelm, 1984; Sundberg & Sundberg, 1990; Weirmanski, 1984; Wraikat, 1991; Wraikat, Sundberg, & Michael, 1991; and the bottom half of subjects in Cresson, 1994). The higher functioning subjects have done better (or have not shown a difference) with SB systems. (Bristow & Fristoe, 1984; Stratton , 1992; Tan, Bredin, Poison, & Grabavac 1995; Potter, Huber, & Michael, 1997; and the top half of subjects in Cresson 1994).
The primary purpose of this study was to manipulate aspects of the SB system to see if two populations of subjects were differentially affected . One group of subjects consisted of highly verbal college subjects; the other, of low verbally skilled subjects with develop mentally disabilities. A secondary purpose was to make another comparison of a SB system with a TB system . This comparison was accomplished by exposing each subject to a matching-to sample task under three conditions and to one condition involving signing-to-sample. In the first condition, all of the symbols on the board remained in a fixed location. In the second condition, the location of each symbol changed after every correct response. In the third condition, all of the symbols were identical and only location was relevant. In the final condition, subjects were taught to make a sign when presented with a word or object.
Initial findings indicated that the college subjects relied heavily on the distinctiveness of each symbol, while the developmentally disabled subjects relied heavily on the location of each symbol. These results, along with a protocol analysis conducted with the college subjects, indicated that the conditional discriminations required in the SB tasks were mediated by TB responding . It was apparent that the developmentally disabled subjects were not engaging in this mediating behavior. The results also indicated that the develop mentally disabled subjects performed better with the TB signs than with the SB symbols, while the college subjects showed no significant difference.
These results may explain the inconsistencies in results from previous studies in this area.
Sundberg, Carl T., "The Comparison of Selection-Based and Topography-Based Verbal Behavior Across Populations" (1998). Dissertations. 1596.