Limitations of Mediated-Interference and Potentiation When Pairing Neutral Flavor Cues

Abstract

Mediated conditioning is the phenomenon in which the elicited representation of a stimulus can modify conditioning even in the absence of the stimulus itself. This occurs when the representation of this stimulus is elicited by another, previously associated stimulus. Kwok et al. (2016) found that pairing two flavors (F1 and F2) together twice allows for mediated interference, wherein the representation of a stimulus (F2) interferes with the learned aversion between a target taste and an illness. Whereas pairing two flavors together six times results in mediated potentiation, wherein this aversion to the target taste is made stronger by the representation of F2. I sought to replicate the results of this study by closely following their procedure and using different flavors for the target and interfering stimuli. I also added control groups that did not receive an interfering flavor during conditioning. Upon the beginning of flavor training, all rats were split into one of six groups (2-P, 2-U, 2-C, 6-P, 6-U, or 6-C). These rats were given either 2 presentations of the cue flavors together or on different days, or 6 presentations of the cue flavors together or on different days. During conditioning, rats received an almond-flavored solution, one of the cue flavors or water, and then illness. No reliable pattern of mediated interference or potentiation was found; all groups drank very similar amounts of almond. However, the varying results of the interference flavor test show that the rats did indeed learn an aversion to the flavor consumed between the almond solution and illness on conditioning day. From these results I concluded that mediated interference and potentiation cannot occur in a serial-conditioning design when the two cue flavors used are neutral stimuli.