Mediated Generalization and Stimulus Equivalence

Abstract

From the 1930s to the 1970s a large number of experimental studies on mediated generalization were published, and this research tradition provided an important context for early research on stimulus equivalence. Mediated generalization and stimulus equivalence have several characteristics in common, notably that both traditions seek to experimentally investigate derived responding among arbitrarily related stimuli in human participants. Although studies of stimulus equivalence are currently being regularly published, few studies investigate mediated generalization in humans today, and the research tradition is mainly of historical interest. The current article will give an account of the origin, the development, and the demise of research on mediated generalization, including a presentation of publication trends, experimental methodology, and the conceptual context research on mediated generalization took place within. Finally, some thoughts on the demise of mediated generalization and its relevance for modern research on stimulus equivalence and other types of derived responding are presented, including reflections on the observability of explanatory variables and the use of inferential statistics.

Keywords: Derived responding; History; Mediated associations; Mediated generalization; Stimulus equivalence.

Fig. 1

Hypothetical data illustrating the savings method commonly used to measure mediated generalization. Note. The figure depicts, in a similar manner to illustrations occasionally seen in the mediated generalization literature, the average number of correct responses across participants per session of 10 trials in an experimental condition consisting of A–B, B–C training, and an A–C test (solid line) and a control group consisting of A–B, C–D training, and an A–D test (broken line). This average difference in correct responding over sessions between the experimental group and the control group is referred to as “savings in learning” and was considered the dependent variable indicating or showing mediated generalization. See the text for further details

Fig. 2

The number of publications on mediated generalization between 1935 and 1984. Note. The figure shows the number of returned results when searching for mediat* generalization, mediat* associat*, or mediat* paradigm* in the PsychINFO database. The results are organized in 5-year blocks from 1935 to 1984