Equivalent Stimuli Are More Strongly Related after Training with Delayed Matching than after Simultaneous Matching: A Study Using the Implicit Relational Assessment Procedure (IRAP)

Bortoloti and de Rose (2009) found evidence that the level of functional transfer is higher in equivalence classes generated by delayed matching to sample (DMTS) than in classes generated by simultaneous matching (SMTS). We attempted to replicate these findings with the Implicit Relational Assessment Procedure (IRAP). Two experimental groups established two equivalence classes, each comprised of faces expressing either anger or happiness and nonsense words. The classes were established with SMTS for one group and with DMTS for the other. Then, nonsense words and the faces were respectively presented as "attribute" and target stimuli in IRAP tasks. The DMTS group yielded the expected IRAP effect; the SMTS group yielded an IRAP effect only when the target was a happy face. It is discussed that DMTS can enhance transfer of "semantic" functions between equivalent stimuli, supporting the idea that the relatedness of stimuli can vary as a function of experimental parameters. (Contains 1 table, 3 footnotes and 3 figures.)