Recombinative Instruction-Following without Reinforcement

The purpose of the present study was to assess whether undergraduate students would correctly follow recombined instructions after two kinds of stimulus pairing procedures with overlapping compound stimuli, and to compare these results with a matching-to-sample procedure. The investigated procedures may be analogous to situations where the listener would learn to comprehend sentences with the syntax “verb + object.” Participants were assigned to three groups that differed regarding the type of training between stimuli that overlapped in a stepwise manner: matching-to-sample (MTS), stimulus pairing (SP), and cued multiple stimulus pairing (CMSP). Relations between pseudophrases (A) and videos of actions related to objects (B), and between pseudophrases (A) and compound abstract symbols (C) were trained in each group (AB and AC training). Performance was tested in selection tasks: stimulus equivalence (BC/CB) and recombined conditional discriminations (AB-r/AC-r); and execution tasks: trained (AD/CD) and recombined (AD-r/CD-r) instruction-following. In the MTS control group, participants had to choose a comparison stimulus according to the sample, in a conditional discrimination task. In the SP condition, participants were asked to observe stimuli that were analogous to the sample and correct comparison of the MTS condition, displayed in sequence in a stimulus pairing task, presented without reinforcement or required selection responses. The CMSP condition used a procedure similar to SP, except S+ were signaled by a hand icon, and S- analogues were presented in the pairing trial. MTS and SP conditions produced similar performances in BC/CB, AB-r/AC-r, AD/CD and AD-r/CD-r testing, whereas CMSP yielded worse results than both. Results indicate that recombined instruction-following may be a product of stimulus pairing procedures, which does not require or reinforce selection responses (SP), even when more than one stimulus is displayed in the pairing situation (CMSP).