Using the precursor to the relational evaluation procedure (PREP) to establish the relational frames of sameness, opposition, an

The present study examined the degree to which relational responding in accordance with sameness, opposition, and distinction could emerge using a precursor to the relational evaluation procedure (pPER). Fifteen adult human participants engaged in a computerized experiment consisting of a variety of trained and tested conditional discriminations. First, participants were shown two stimulus objects on the computer screen and were asked to choose between two arbitrary colored response options that functioned to describe the above stimuli as "same", "opposite", or "different". Second, participants were tested on the symmetrical relations they were initially trained on, as well as novel stimuli pairs that were functionally equivalent to the trained stimuli. All participants were able to perform at high levels of accuracy during testing with either previously trained or novel stimulus items. The present data suggest that non-matching to sample means of establishing relational responding to same, difference, and opposite stimuli are possible and should be explored in greater detail than reported in the published literature.