Role of Ingestion in Aversion Learning

Abstract

<p>The role of ingestion in taste and odor aversion learning is usually considered to be limited to bringing subjects in contact with the gustatory and olfactory conditioned stimuli. Results of the present series of experiments indicate that ingestion not only facilitates contact with certain cues, but under certain circumstances, also facilitates the conditioned aversion behavior. Rats that drink a novel-flavored substance prior to toxicosis evidence stronger learned aversions to the taste in subsequent drinking preference tests than subjects that experience the novel flavored substance in the absence of ingestive behaviors during conditioning. Similarly, ingestion during odor-aversion learning results in stronger aversion behavior, provided subjects drink the same solution during postconditioning tests as had been ingested during conditioning. Control groups demonstrated that the facilitory effect of ingestion on odor-toxicosis learning is not a result of acquired aversions to the flavor of the solution ingested. Rather, the results are consistent with the hypothesis that subjects drinking during odor-toxicosis conditioning acquire aversion not only to the CS odor and the flavor of the ingested solution. Additional evidence suggests that this interaction probably occurs in the central nervous system and not at the level of the receptors.</p>