Generalization of the CS- preexposure effect transfers to taste- aversion learning

Abstract

Rats repeatedly exposed to a maple, vanilla, banana, or water solution were subsequently poisoned with lithium chloride after drinking the maple solution. Subjects preexposed to water showed the strongest aversions to maple, followed, in descending order, by rats preexposed to banana, vanilla, and maple. These results suggest that the effects of prepoisoning experience with a novel flavor generalized to the maple CS and interfered with the development of the maple aversion. The technique reported here is potentially applicable to study of gustatory discrimination processes. 23Ingestion of a distinctively flavored solution has two effects in rats: (1) their subsequent intake of this flavored fluid is enhanced (e.g., Domjan, 1976), and (2) they are retarded in the acquisition of an aversion to this flavor (e.g., Revusky & Bedarf, 1967). The enhanced intake effect of flavor preexposure shows generalization, i.e., exposure to a novel flavored solution increases subsequent ingestion not only of the exposed flavor but also of other novel flavors (Siegel, 1974). The purpose of the present experiment was to determine whether generalization of experience with a flavor is detectable in taste-aversion learning. Klein, Mikulka, and Hamel (1976) reported that preexposure to one concentration of a sucrose solution had no effect on the acquisition of an aversion to a different concentration of sucrose.Their findings suggest that es preexposure influences taste-aversion learning only if the substance paired with illness is the same as that experienced previously.The present experiment investigated stimulus control and the interaction of prepoisoning familiarization and taste-aversion learning using different flavors rat her than different concentrations of the same flavor. Groups of rats were given extensive preexposure to one of several flavors. Then they were poisoned after drin king one of the solutions. If generalized preexposure transfers to taste-aversion learning, then it should interfere with the establishment of an aversion to a flavor other than the preexposed flavor.The author wishes to thank M. E. Dimperio for technical assistance and J. M. Juraska for helpful comments and suggestions. Requests for reprints should be addressed to J. M. Dawley,

Neophobias and conditioned taste aversions in rats following exposure to novel flavors

“…The apparent differences between the tastes involved tend to support these investigators in their contention that they were observing the consequence of prior exposure to novel tastes per se rather than stimulus generalization; however, the broad generalization across tastes recently observed by Dawley (1979) indicates that stimulus generalization may have influenced some of these studies. Braveman and Jarvis (1978) and Austin (Note I), using single-bottle tests, found that prior exposures to novel substances reduced neophobia in adult animals.…”

“…Previous research on these issues appears, in the light of Dawley's (1979) data, to have possibly been affected by stimulus generalization between flavors. Braveman and Jarvis (1978) made the best effort to date to examine the influence of stimulus generalization in this paradigm.…”

“…The basis for this inconsistency is also uncertain, but likely is due to differences in the test trial procedures and differences in the pretraining and test flavors, the latter possibly resulting in more stimulus generalization across flavors in the Tarpy and Mcintosh (1977) study. The tendency of rats to generalize across flavors that, to humans, seem highly dissimilar (Dawley, 1979) emphasizes the importance of the particular flavors used for pretraining and training. The present experiments suggest that such stimulus generalization is the most probable basis for the seemingly maladaptive reduction in propensity to form CTAs reported by Tarpy and Mcintosh (1977) following exposure to multiple novel flavors.…”

The effects of flavor preexposure and test interval on conditioned taste aversions in rats

“…It has also been shown that prior experience with a flavor different from the CS can similarly attenuate a conditioned aversion (Dawley, 1979;Kraemer & Roberts , 1984). The conventional interpretation of the preexposure effect has been that a prior flavor experience in some way disrupts the acquisition of a CS aversion, and a variety of mechanisms have been offered to account for this putative disruption (Best & Barker, 1977;Best & Gemberling, 1977;Kalat & Rozin, 1973).…”

Release from latent inhibition with delayed testing

“…Nonreinforced preexposure to a CS, or to a stimulus similar to the CS, decreases the subsequent strength of conditioned responding expressed to the CS (Dawley, 1979;Lubow, 1973;Mackintosh, 1983). This wellestablished phenomenon, termed latent inhibition (LI), has appeared across a wide range of CSs, USs, and proeedures (Albert & Ayres, 1989;Elkins, 1973;Lubow, Markman, & Allen, 1968;Lubow & Moore, 1959;Reiss & Wagner, 1972).…”