A Comparison of Stimulus Set Sizes: Systematic Replication with Operant Analysis Acquisition Criteria

We conducted a systematic replication of Kodak et al.’s Journal of Applied Behavior Analysis, 53(1), 265–283 (2020) and Vladescu et al.’s Behavior Analysis in Practice, 14(1), 193–197 (2021) experiments on the effects of stimulus set sizes on skill acquisition. The researchers manipulated the stimulus set sizes by teaching 3, 6, and 12 sight words simultaneously during learn unit instruction. Researchers taught participants until the participant’s responding reached the acquisition criterion for 12 different sight words per set size condition. The acquisition criterion was set for an individual operant, whereby when accuracy met criterion for a single sight word, that sight word was replaced in the following session. The results showed that the set-size-3 was more efficient in producing criterion-level responding during acquisition than the set-size-6, and -12, which was consistent with Vladescu et al.’s findings. However, the set-size-12 reliably produced the highest maintenance levels for all participants. The definition of “effectiveness” based on acquisition or maintenance was discussed.