This study is a step forward in the difficult task of analyzing the transformation of functions via hierarchical relations. Eight participants underwent a computer task with five phases. During Phase 1, four stimuli were trained to become the following relational cues: INCLUDES, BELONGS TO, SAME, and DIFFERENT. In Phase 2, three equivalence classes were trained and tested (A1-B1-C1-D1; A2-B2-C2-D2; A3-B3-C3-D3). During Phase 3, inclusion relations were first established, by using the INCLUDES and BELONGS TO relational cues, between the to-be lower levels of the hierarchy, namely A1/B1, A2/B2, and A3/B3; and stimuli X.1, X.2, and Y.1, respectively. Then, the INCLUDES relational cue was used to establish inclusion relations between X.1/X.2 and X, and between Y.1 and Y, so that X and Y would become the most inclusive levels of two separate hierarchical networks. In Phase 4, X.1 was established as cold, D2 as heavy, and C3 as sweet. Lastly, in Phase 5 (Critical Test), seven stimuli from both hierarchical networks were tested for the transformation of functions. Five of the six participants who made it to this test responded correctly. Implications, limitations, and further research are discussed
