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Pilgrim and Galizio (1995) reversed baseline conditional
discriminations after the emergence of equivalence classes.
College students' performance was consistent with the reversed
baselines in subsequent symmetry tests, but was consistent with
pre reversal baselines in transitivity tests. The present study
replicated systematically Pilgrim and Galizio's experiment.
Following the emergence of two four-members equivalence
classes, 9 college students were exposed to reversal of a baseline
conditional discrimination, training of a new conditional
discrimination, reversal of another baseline conditional
discrimination, and return to the original baseline. Both symmetry
and transitivity performances were consistent with the reversed
baselines for most participants. These results may be due to
increased strength of the reversed baselines, trained with
continuous reinforcement and reviewed before probes, whereas
Pilgrim and Galizio trained reversals with intermittent
reinforcement in the context of probing. The use of different stimuli
and stimulus display may have also affected the results.