Lack of reacquisition in learned taste aversions

Abstract

Following ingestion of either water (Experiment II or saccharin (Experiment 2), experimental groups of rats were poisoned with lithium chloride and acquired an aversion to the ingested fluid. This aversion gradually extinguished and, in both experiments, was not reacquired when fluid intake was again followed by poisoning. These results are in marked contrast to usual findings of very rapid relearning following extinction with conditioning preparations other than taste-aversion learning.When a distinctive flavor is followed by toxicosis, animals generally subsequently evidence an aversion for that flavor. This taste-aversion learning exhibits several features which distinguish it from more traditional learning preparations (see Revusky & Garcia, 1970), and some investigators have suggested that such flavor-illness associations are a distinct, biologically specialized form of learning (e.g., Rozin & Kalat, 1971). However, other investigators have suggested that the general principles underlying taste-aversion learning and other forms of learning may be similar, with the dramatic differences being primarily of a quantitative nature (e.g., Best, 1975).The results of the present experiments suggest one qualitative difference between taste-aversion learning and other forms of learning. It has been dernonstrated in a variety of conditioning situations that the reinstatement of a conditional response following extinction is relatively rapid. That is, a response which has been classically conditioned through repeated conditioned stimulus (CS)-unconditioned stimulus (UCS) pairings, then extinguished by CS-alone presentations, is usually reestablished by CS-UCS pairings much more quickly than if there were no prior history of CS-UCS pairings (e.g., Ellson, 1938; Pavlov, 1927, p. 59). In contrast with these findings, the results of the present experiments, using the tasteaversion situation, indicated that prior acquisitionextinction experience did not facilitate reacquisition -indeed, it profoundly retarded reacquisition.We have previously reported experiments concerning the acquisition and extinction of an aversion to water, based on lithium chloride (LiCl) toxicosis (Danguir, 1975). In Experiment 1 of the present paper, the postextinction reacquisition of such a learned water aversion was investigated. In Experi-The authors are grateful to N. E. Rowla~d and P. Rozin for criticisms of an earlier draft of this manuscript, and to Dr. S. Siegel for his editorial assistance, Requests for reprints should be addressed to Jaber Danguir, Laboratoire de Neurobiologie des Regulations, College de Franee, 11 plaee Mareellin Berthelot, 75231 Paris Cedex 05, France. ment 2, the reacquisition of a learned saccharinaversion was assessed. EXPERIMENT 1 MethodTwenty male rats of the Wistar strain were individually housed with food ("Extralabo M 25") available ad lib. Tap water was available only from 10:00 to 10:15a.m. daily. The experiment was eondueted over a 23-day period. The rats were adapted to the drinking schedule for the first 8...

Impact of brief or extended extinction of a taste aversion on inhibitory associations: Evidence from summation, retardation, and preference tests

“…With the present procedures, we found no evidence of inhibition after only three extinction trials. The inhibition finding after nine trials is consistent with findings from previous retardation tests (e.g., Calton et al, 1996;Danguir & Nicolaidis, 1977;Hart et al, 1995, Experiment 2;Schachtman et al, 2000). Experiment 2's summation test result, however, suggests that positive summation test results obtained after extinction in CTA are due to generalization decrement (see also Aguado et al, 2001).…”

“…Latent inhibition may simply be stronger after nine extinction trials than after three (cf. Calton et al, 1996;Danguir & Nicolaidis, 1977;Hart et al, 1995). However, in the absence of other evidence, the results from this experiment do not rule out the possibility that the control conditions produced conditioned inhibition, in which case the experimental condition (Group 9E in Experiments 1 and 2) could be interpreted as having produced conditioned inhibition.…”

“…The renewal effect has been shown after three trials (Rosas & Bouton, 1997); it has not been assessed after more than three extinction trials within the same experiment. Slow reacquisition has been shown after eight or nine extinction trials, but not after only three (Calton et al, 1996;Danguir & Nicolaidis, 1977;Hart et al, 1995;Schachtman et al, 2000).…”

“…This has been suggested by several studies. For example, Schachtman (e.g., Calton, Mitchell, & Schachtman, 1996;Hart, Bourne, & Schachtman, 1995) has provided evidence that a conditioned flavor simply extinguished for eight or nine trials subsequently passes summation and retardation tests (see also Danguir & Nicolaidis, 1977;Schachtman, Threlkeld, & Meyer, 2000). However, in a retardation test, Hart et al (1995, Experiment 1) did not find evidence consistent with conditioned inhibition to a flavor extinguished for only three trials.…”

“…Another possibility is that with CTA procedures such as those used in prior studies, a strong form of demonstrable inhibition (e.g., conditioned inhibition) develops only after more than approximately three extinction trials. Such a suggestion has been made (e.g., Hart et al, 1995), and some evidence for it has accumulated (e.g., Calton et al, 1996;Danguir & Nicolaidis, 1977;Hart et al, 1995;Schachtman et al, 2000). However, to our knowledge, no direct comparisons of conditioned inhibition after different numbers of extinction trials have been conducted.…”