Tests for inhibition after extinction of a conditioned stimulus in the flavour aversion procedure

Abstract

In four experiments, rats received flavour aversion conditioning followed by extinction. The flavour was then subjected to retardation and summation tests. Experiment 1 showed that reacquisition of an extinguished flavour aversion was retarded with respect to the performance shown by rats for whom the flavour was novel. No retardation was found, however, with respect to a control group that had been given non-reinforced pre-exposure to the flavour. Experiment 2 demonstrated that extinction showed the same sensitivity to the effects of a retention interval as did latent inhibition, consistent with the view that the retardation effect was a consequence of the occurrence of latent inhibition during extinction. An extinguished stimulus was also found to alleviate the response governed by a separately trained excitor in a summation test (Experiments 3 and 4), but the size of this effect did not exceed that produced by a control stimulus when the procedure used ensured an equivalent aversion to the test excitor in the two cases. These results challenge the proposal that extinction can turn a stimulus into a net inhibitor.

Savings in classical conditioning in the rabbit as a function of extended extinction

“…A similar asymmetry between reacquisition and latent inhibition has been observed by Aguado et al (2001) in taste-aversion learning. They found that reacquisition after extinction was less retarded than latent inhibition after extensive preexposure to the CS.…”

“…In taste-aversion learning in rats, rapid reacquisition has been observed (Revusky & Coombes, 1979), but "slow reacquisition" has been more common (Aguado, de Brugada, & Hall, 2001;Calton, Mitchell, & Schachtman, 1996;Hart, Bourne, & Schachtman, 1995). For example, Hart et al (1995) found that reacquisition was retarded relative to a "learningexperienced" control group that had received training and extinction with an orthogonal taste, for which there was little, if any, stimulus generalization.…”

“…These experiments stem particularly from Ricker and Bouton's (1996) conclusion that brief acquisition training followed by massive extinction should result in retarded reacquisition (see also Aguado et al, 2001;Calton et al, 1996;Hart et al, 1995). Accordingly, we examined reacquisition in two different response systems in the rabbit-namely, the NM response (Experiment 1) and the heart rate (HR) response (Experiment 2).…”

Extinction revisited: Similarities between extinction and reductions in US intensity in classical conditioning of the rabbit’s nictitating membrane response

“…Further afield, there is recent evidence that rapid reacquisition can be considerably diminished in the rabbit NM preparation when there is massively extended extinction training-for example, 27 CS-alone trials for every original CS-US trial Medina, Garcia, & Mauk, 2001). These recent findings are heading in the direction of the retardation in reacquisition that has been seen in rats when extended extinction has been conducted (Bouton & Swartzentruber, 1986Carlton, Mitchell, & Schachtman, 1996;Hart, Bourne, & Schachtman, 1995; but see Aguado, de Brugada, Hall, & Agate, 2001).…”

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

“…However, no control conditions were included to assess stimulus generalization decrement on the test. The novel combination of saccharin and vinegar may have distracted the E-group rats and/or disrupted their drinking (Aguado et al, 2001). This is of particular concern for Group 9E because it passed the test.…”