The Psychological Record, 2013, 63, 157–174
Jennifer M. Kinloch is now affiliated with The University of Auckland, New Zealand.
This research was supported by a Top Achiever Doctoral Scholarship from the Tertiary Education
Commission of New Zealand (TEC).
Correspondence concerning this article should be addressed to Jennifer Kinloch, School of
Population Health, The University of Auckland, P.O. Box 18288, Auckland 1743, New Zealand. E-mail:
MATCHING- TO- SAMPLE AND STIMULUS- PAIRING- OBSERVATION
PROCEDURES IN STIMULUS EQUIVALENCE: THE EFFECTS OF
NUMBER OF TRIALS AND STIMULUS ARRANGEMENT
Jennifer May Kinloch, James Stewart Anderson McEwan, and T. Mary Foster
The University of Waikato, New Zealand
Studies comparing the effectiveness of the stimulus- pairing- observation and
matching- to- sample procedures in facilitating equivalence relations have
reported conflicting findings. This study compared the effectiveness of these
procedures and examined the effect of stimulus arrangement and the number
of training trials completed prior to each exposure to tests for symmetry and
equivalence. Overall, the matching- to- sample procedure resulted in a greater
percentage of participants demonstrating equivalence, and with fewer training
trials, than did the stimulus- pairing- observation procedure. The one- to- many
stimulus arrangement was more effective than the many- to- one and linear
arrangements, overall. However, there was an interaction between the type of
training procedure and stimulus arrangement. Participants who completed 120
training trials prior to each test were more likely to demonstrate equivalence
than participants who completed 60 trials. This appeared to be the result of
completing a greater number of trials prior to each test rather than of the
number of training trials completed overall.
Key words: stimulus equivalence, matching- to- sample, associative learning,
operant conditioning, humans
Arbitrary relations can be derived between words, events, or other stimuli without
explicit training or association (Blackledge, 2003). These relations provide a framework by
which the function of words, objects, events, or other stimuli can be evoked by other
words, objects, events, or other stimuli. Such relations have been used to explain the
development of emotional reactions to words, events, or objects that have not previously
been encountered or that have never been explicitly paired with an aversive event
(Dougher, Auguston, Markham, & Greenway 1994). By this argument, many human
psychological problems are the result of the inadvertent pairing or association of objects or
stimuli with each other.
Sidman (2009) provided an overview of the most studied of the arbitrarily derived
relations, stimulus equivalence. Establishing stimulus equivalence experimentally normally
starts by teaching the participant relations between pairs of stimuli. Multiple sets of three or
more stimuli are normally used. For example, Set 1 may contain three stimuli (A, B, and C).