Markham, R. G., & Markham, M. R. (2002).
On the role of covarying functions in stimulus class formation and transfer of function.
Journal of the Experimental Analysis of Behavior,
78, 509-525.
This experiment investigated whether directly trained covarying
functions are necessary for stimulus class formation and transfer
of function in humans. Initial class training was designed to
establish two respondent-based stimulus classes by pairing two
visual stimuli with shock and two other visual stimuli with no
shock. Next, two operant discrimination functions were trained to
one stimulus of each putative class. The no-shock group received
the same training and testing in all phases, except no stimuli
were ever paired with shock. The data indicated that skin
conductance response conditioning did not occur for the shock
groups or for the no-shock group. Tests showed transfer of the
established discriminative functions, however, only for the shock
groups, indicating the formation of two stimulus classes only for
those participants who received respondent class training. The
results suggest that transfer of function does not depend on
first covarying the stimulus class functions.
Key words: stimulus classes, stimulus equivalence, respondent
conditioning, skin conductance response, button press, adult
humans