Understanding complex behavior: the transformation of stimulus functions.

Geckeler et al. (2000) wrote a narrative review. They pulled together early lab work on stimulus equivalence.

The goal was to show how stimulus functions change when stimuli become related. The authors urged readers to describe these changes with Relational Frame Theory (RFT) words instead of older terms.

The review found solid evidence that functions can transform through derived relations. If A scares you and A is equivalent to B, B can also scare you without direct training.

The paper makes the case that RFT language—like "transformation of function"—captures this process better than older labels.

Ninness et al. (2006) extends the review by showing the effect in college math. After brief equivalence training, adult students treated new equations like graphs they already knew. A quick rule or reward shift then flipped which form they picked.

Pérez-González et al. (2003) also extends the review. They showed that contextual cues alone can transfer control to brand-new conditional discriminations. No extra training was needed.

Aman et al. (2002) adds a twist that seems like a contradiction but is not. Shock pairing alone created a stimulus class, and later a discriminative function moved to other members. The review said covariation history matters; this study shows class membership can override it when equivalence is present.

If you teach conditional discriminations, start using RFT terms in your notes and team meetings. Say "transformation of function" when a learner reacts to a new stimulus because it is related to a trained one. This habit keeps your language in line with current evidence and makes reports clearer to other BCBAs.