Teaching coin equivalences via matching to sample.

A moderately mentally retarded woman learned coin equivalences (with 5-, 10-, and 15-cent values) via matching to sample. When taught to match two different coin stimuli to a printed price of equal value, she could then match the coin stimuli to each other and state their values without further training. Additional coin-matching and naming performances emerged after establishing the equivalence between a new coin stimulus and one member of an existing class of equivalent stimuli. The study extends research on stimulus class formation by examining its usefulness in a new application, in teaching a skill repertoire that requires mastery of large numbers of individual performances-monetary equivalences. Further, the study suggests efficient strategies for teaching functional money skills to developmentally limited populations.