Toxiphobia conditioning with exteroceptive cues

Abstract

The types of conditioned properties acquired by novel (i.e., nonpreexposedl or familiar (i.e., preexposedl exteroceptive cues that were paired with toxicosis, in the absence of a flavor CS, were evaluated in four experiments. In Experiment 1, the conditioned properties of novel exteroceptive cues served to block the acquisition of an aversion to a flavor CS during flavor conditioning and to suppress the ingestion response during flavor testing; animals failed to suppress their ingestion of either the flavor CS or a neutral flavor when tested in the absence of the exteroceptive CS, but suppressed their ingestion of both the flavor CS and the neutral flavor when tested in the presence of the exteroceptive CS. In Experiment 2, preexposed exteroceptive cues that had been paired with toxicosis failed to provide evidence of such conditioned properties. Experiment 3 demonstrated that preexposed contextual cues that were reinforced in compound with novel exteroceptive cues failed to acquire the conditioned properties acquired by nonpreexposed contextual cues under the same conditions of reinforcement. Finally, in Experiment 4, the conditioned properties of the novel exteroceptive cues served to evoke a conditioned gastrointestinal response that gradually extinguished as a function of repeated nonreinforced exposures to the exteroceptive cues, and, in the absence of such extinction, the conditioned properties served to block the acquisition of a flavor aversion.

Lack of reinstatement of an extinguished taste aversion

“…Instead, it appears to reflect a more general tendency to decrease fluid consumption in the context in which the reinstatement injection was received. Krane (1980) and Willner (1978) have reported a similar decrease in general fluid consumption in a context in which rats received injections of LiCl. Such an effect in the present experiment appears to have occurred independently of any reinstatement of the saccharin aversion, because Group R's preference for saccharin did not decrease as a result of the reinstatement injection.…”

“…Two considerations suggest the possibility that the present experiments might not have fulfilled this requirement. First, there is evidence to suggest that if exteroceptive (contextual) cues are to be associated with LiCl, they must be novel when they are paired with LiCI (e.g., Archer & Sjoden, 1981;Krane, 1980). In the traditional reinstatement design, the animal is exposed to the US in a familiar context; the test context was not novel when the rats were given reinstatement injections in the present experiments.…”

“…On this view, if LiCI injections can be associated with contextual stimuli, and if contextual stimuli and tastes summate (cf. Krane, 1980;Willner, 1978), then it should be possible to reinstate an extinguished taste aversion with LiCI injections following extinction. Our results suggest that this may not be the case.…”

“…Recent evidence suggests that the conditioning of contextual stimuli may also be involved in taste aversion learning (e.g., Archer & Sjoden, 1981;Archer, Sjoden, Nilsson, & Carter, 1979Batson & Best, 1979;Krane, 1980;Willner, 1978). We therefore began our investigation of the reinstatement of taste aversions by attempting to determine whether reinstatement would occur only if the US were presented in the context in which the aversion was subsequently tested for reinstatement.…”

Biological constraints revisited: A critique

“…Thus, subsequent experimental investigations have demonstrated that taste cues are effective in the induction of aversion learning to shock if the CS-US interval can be appropriately adjusted to the temporal characteristics of taste cues (Krane & Wagner, 1975), and that exteroceptive cues can be conditioned to ingestional USs (Delamater, LoLordo, & Berridge, 1986;Krane, 1980) if an appropriate CR measurement is selected or if shock-site is appropriate (Delamater & Tait, 1987). Collectively, these subsequent observations show that task-specific interpretations based on manipulation of general-process factors can provide an alternative interpretation of the retarded-learning observations found with crossover paradigms.…”