The Expansion of Equivalence Classes Through Simple Discrimination Training and Fading

Abstract

AB, BC, CD, and DE were established by conditional discrimination training. Symmetry, transitivity, and equivalence tests were then passed demonstrating the formation of 5-member equivalence classes. These tests were passed even though they were conducted in the absence of baseline relations. A new stimulus (F) was then linked to a class member (A) by stimulus fading conducted in the context of simple discrimination training. Thereafter, subjects passed FB, FC, FD, FE, BF, CF, DF, and EF tests, demonstrating that F functioned as a new member of the A-E class. The expansion of equivalence classes can also be accomplished by the use of simple discrimination training combined with stimulus fading, in addition to the typical use of conditional discrimination training. Equivalence classes, then, can be defined independently of conditional discrimination procedures.