Acquired Equivalence in Conditioned Pleasant and Unpleasant Stimuli

Acquired equivalence is a form of conditioning where two physically dissimilar stimuli, followed by the same outcome, form an association where a change in the outcome of one may also transfer to the other. Previous studies observed this with neutral and affective stimuli. We investigated whether the valence can be reversed from pleasant to unpleasant and vice-versa through acquired equivalence in conditioned stimuli. Twenty-seven participants were selected for the experiment. Four shapes were selected as conditioned stimuli (CS), and two pleasant and unpleasant auditory stimuli as unconditioned stimuli (UCS). The experiment included Habituation, Acquisition, and Reversal of UCS phases. The acquisition phase involved conditioning 2 shapes with a pleasant UCS and 2 with an unpleasant UCS. In the reversal of UCS phase, one of the shapes previously paired with unpleasant UCS was paired with pleasant UCS and vice-versa. The results indicate a significant transfer of valence for CS undergoing direct reversal of UCS and an acquired equivalence for unpleasant to pleasant transfer. We also reevaluate the mechanism of association transfer through mediated generalisation and connectionist network models. Future research can explore anxiety interventions by reducing the unpleasantness of a stimulus by conditioning another associated, approachable stimulus with a pleasant stimulus.