A precursor to the relational evaluation procedure: Analyzing stimulus equivalence II

A series of experiments examined the precursor to the relational evaluation procedure (pREP). The pREP is capable of facilitating derived relational r esponding, but it is less effective than matching-to-sample (MTS) in produc ing equivalence class formation. Part 1 of the present study tested possibl e reasons for the inferiority of the pREP relative to MTS. The first two ex periments compared the performances of subjects on two modified versions of the pREP with their performances on a simultaneous MTS procedure. The modi fications did not improve performances on the pREP. Experiment 3 compared t he pREP with a delayed MTS procedure but again MTS was more effective than the pREP in producing equivalence. Part 2 of the study determined whether p REP equivalence responding could be facilitated by preexposing subjects to a history of MTS training and testing. In Experiment 4, subjects were train ed and tested on a MTS procedure until they reliably produced both symmetry and equivalence, and were then exposed to pREP training and testing using the same stimuli, and relations among stimuli, as employed for the MTS proc edure, Following this, subjects were exposed to pREP training and testing u sing novel stimuli. All subjects reliably produced both symmetry and equiva lence responding on the pREP with both familiar and novel stimuli. Experime nt 5 determined whether using the same stimulus sets across the two procedu res was necessary. Results showed that if symmetry and equivalence were sho wn on a MTS procedure followed immediately by pREP training and testing usi ng novel stimuli, only 2 out of 4 subjects successfully demonstrated both s ymmetry and equivalence using the latter procedure.