Hayes et al., (in press)

Relational Frame Theory (RFT) is the simplest form of operant theory since it claims nothing more than a particular type of behavior, arbitrarily applicable derived relational responding, is an operant. While the theory is simple, its implications are not, and adoption has been slow until recently. RFT was first formally described in 1985 and in the 35 years since, hundreds of studies have been conducted on relational learning from an operant point of view. The present paper briefly summarizes that history and examines some of its key claims. So far, the empirical program delineated by RFT has held up remarkably well. Future directions are delineated that will enable a more comprehensive evaluation of the importance of the RFT research program, and a more thorough exploration of its profound implications.