Fast responding and the formation of equivalent classes.

A group of ten individuals participated in an experiment with limited hold (LH) contingencies for responding to sample and comparisons. The LH was set to 0.7 s and 1.2 s in a one-to-many (OTM) training structure. After reaching the training criterion with at least 90% accuracy, a test for derived relations was implemented. None of the participants responded in accordance to stimulus equivalence, indicating that the responding with a requirement of fast responding prevents equivalence class formation.