The transformation of stimulus functions is said to occur when the function
s of one stimulus alter or transform the functions of another stimulus in a
ccordance with the derived relation between the two, without additional tra
ining. This effect has been demonstrated with a number of derived stimulus
relations, behavioral functions, experimental preparations, and subject pop
ulations. The present paper reviews much of the existing research on the tr
ansformation of stimulus functions and outlines a number of important metho
dological and conceptual issues that warrant further attention. We conclude
by advocating the adoption of the generic terminology of relational frame
theory to describe both the derived transformation of stimulus functions an
d relational responding more generally.