Experimentally induced taste aversions in humans: effects of overshadowing on acquisition.

This study used vection-induced symptoms of motion sickness as an unconditioned stimulus to condition food aversions in humans and to evaluate the efficacy of an overshadowing agent (novel flavored candy: CS2) to attenuate acquisition of the aversion. Subjects unfamiliar with a target food (CS1) were assigned to one of the following three groups which were identical except for order of exposure to stimuli: Taste Aversion Group (CS1-US-CS2-Test), Control Group (US-CS1-CS2-Test), and Overshadowing Group (CS1-CS2-US-Test). Subjects were tested on aversion ratings and consumption of the target flavor and ratings of the overshadowing agent. Subjects in the Taste Aversion group rated the target flavor as significantly more aversive and consumed less of it, although not significantly so, that did those in the Control group. The Overshadowing group consumed significantly more of the target food than did the Taste Aversion Group. Considering only subjects unfamiliar with the overshadowing agent, those in the Overshadowing group rated the agent (CS2) as significantly more aversive than the Taste Aversion and Control groups. Implications of these findings to taste aversions in humans are discussed.