In stimulus equivalence, untaught abilities arise spontaneously out of a few that are learned through direct experience. Students of psychology often wonder where the most creative and flexible aspects of thought come from; stimulus equivalence may provide a partial explanation. Until recently, scientists had a limited understanding of the experiences that create stimulus equivalence. Contemporary research on the building blocks of stimulus equivalence provides insights into some complex everyday problems, including that of how to teach for maximum benefit. This chapter defines stimulus equivalence, provides some tips for understanding the rather technical methods that are used to study it, and illustrates some applications of the insights that are derived from the research. The chapter also shows how stimulus equivalence is related to ...