Abstract

Background/Objective: Blocking occurs when previous conditioning with one stimulus reduces, or blocks, conditioning to a second redundant stimulus added later in training or conditioning procedures. Previous research has suggested that blocking may occur during equivalence class formation. Although both match-to-sample and respondent-type training have been used to establish equivalence classes, blocking has only been studied using match to sample procedures. Previous research on blocking in equivalence class formation did not utilize control groups, limiting the conclusions drawn from those studies. Thus, the purpose of the present study was to compare match-to-sample and respondent-type training for their susceptibility to blocking in three-member equivalence classes using control conditions.
Method: A total of 27 participants were exposed to match-to-sample or respondent-type training procedures to form equivalence classes using a linear series training structure. Within each training procedure, one group of participants was exposed to a blocking condition and one was not.
Results: Results indicated that the blocking did not occur for the 4 of 6 participants who formed equivalence classes. Patterns of responding that would be expected if blocking occurred were seen in both experimental and control conditions.
Conclusions: Results obtained in the current study indicate that some processes other than blocking are involved when stimuli fail to enter equivalence classes. Future research should examine other processes involved when stimuli fail to enter into equivalence classes after training.