The extinction procedure modifies a conditioned flavor preference in nonhungry rats only after revaluation of the unconditioned stimulus.

Abstract

In 3 experiments rats experienced 2 flavors, each paired with sucrose, in order to establish a conditioned preference to each. One (flavor Fe) was then presented alone (an extinction procedure) prior to a choice test between Fe and the flavor that did not undergo extinction (Fne). Hungry rats showed a preference for Fne over Fe (Experiment 1A), but rats that were not food-deprived showed no effect of extinction when given a choice between Fe and Fne immediately after extinction (Experiment 1B) or after an interval in which reexposure to sucrose was given (Experiment 2). The extinction procedure was not without effect, however, as Fe was preferred over Fne after sucrose had been devalued by pairing with lithium chloride, and Fne was preferred over Fe after a procedure likely to enhance the value of the sucrose (Experiment 3). The explanations considered propose that preference conditioning establishes a range of associations between the flavor and the various properties of sucrose (its nutritional value, its taste, the hedonic reaction it evokes). It is suggested that the form of learning that mediates revaluation effects is sensitive to extinction whereas that responsible for performance on a consumption test is not. (PsycINFO Database Record

Sucrose-based flavor preferences in rats: Factors affecting detection of extinction.

“…By contrast, making the rats hungry would promote the formation and use of an orthodox association between flavor and nutritional consequences and such an association would be subject to normal extinction effects. Just this result, an effect of the extinction treatment in hungry rats but not in rats that are sated, has been reported by González et al (2016, Experiments 1A and 1B) and by Harris et al (2004, Experiments 2A and 2B).…”

“…Presentation of the target flavor alone, in the absence of sucrose, constitutes an extinction procedure and loss of a conditioned preference would be expected if the preference depends on an orthodox association. However, it has been demonstrated repeatedly that the preference can be sustained despite extended extinction training (e.g., Albertella & Boakes, 2006; Dwyer et al, 2009; González et al, 2016, Experiments 1B and 2; Harris et al, 2004, Experiments 1A and 1B; but see Delamater, 2007). A feature of these experiments is that the subjects have not been food-deprived during training, leading to the suggestion that the critical property of sucrose in these circumstances will not be its nutritional properties but rather its sweet taste.…”

Facilitation and retardation of flavor preference conditioning following prior exposure to the flavor conditioned stimulus

“…Rats were divided in two groups, one receiving pre-exposure to the flavor to be used as the CS (group Pre, for pre-exposed to the flavor), and the other given pre-exposure only to water (group NPre, for not pre-exposed to the flavor). The flavor (almond) was the same as that used in the previous studies (González et al, 2015(González et al, , 2016 in which an initial aversion was observed. All subjects then received a phase of training in which the flavor was presented mixed with a sucrose solution.…”

“…Second, we need to confirm that the effect seen in Experiment 1 is indeed a consequence of the nature of the flavor used as the CS. González et al (2016), having noted that this particular almond flavor was initially disliked by rats, sought alternatives, and found weaker solutions of flavorings from a different supplier that were initially neutral but that supported flavor preference conditioning. Accordingly, we included groups in this experiment that used a neutral flavor (vanilla) as the CS.…”

“…It has been suggested that flavor-nutrient learning involves a form of expectancy or predictive learning (e.g., Campbell, Capaldi, Sheffer, & Bradford, 1988;Drucker, Ackroff, & Sclafani, 1994) that depends on standard associative mechanisms, and thus obeys the standard laws of conditioning, being susceptible, for example, to blocking, latent inhibition, extinction, and so on (e.g., Garcia-Burgos & González, 2012;Garcia-Burgos, González, & Hall, 2013;Harris et al, 2000). On the other hand, flavor-taste learning has been thought to involve a mechanism that produces a change in the hedonic properties of the flavor (the flavor comes to Btaste better^; Drucker et al, 1994); this mechanism could operate according to different laws (Campbell et al, 1988;De Houwer, Thomas, & Baeyens, 2001;Drucker et al, 1994;Pearce, 2002) making it resistant to blocking, extinction, and latent inhibition (Garcia-Burgos et al, 2013;González, Garcia-Burgos, & Hall, 2014;González, Morillas, & Hall, 2015, 2016Harris et al, 2000; see also Harris, Shand, Carroll, & Westbrook, 2004). The present series of experiments focuses on the latent inhibition procedure.…”