Analysis of second-order odor-aversion conditioning in neonatal rats: Implications for Kamin's blocking effect.

Abstract

It has been reported that neonatal rats acquire first-order conditioned aversions to olfactory stimulation experienced prior to drug-induced illness. Experiment 1 demonstrates that the neonate will also acquire a second-order conditioned odor aversion and that the second-order aversion is not affected by extinguishing the first-order aversion. The effectiveness of the secondorder conditioning paradigm (i.e., Si~* US; S 2 -* Sj) and a sequential blocking paradigm (i.e., S t -*US; S 2 ~*Si->US) also were compared. These comparisons revealed (a) that the occurrence of the US in the second phase of the blocking treatment interfered with second-order conditioning (Experiment 3) and (b) that the temporal proximity of US occurrence to the S 2 ~* Si episode was a critical determiner of the degree to which such interference was observed; that is, the more proximate the S 2 -S l and US events, the more US occurrence interfered with second-order conditioning (Experiment 4). Implications of these findings for theories of conditioning are discussed.

Blocking with serial and simultaneous compounds in a trace conditioning procedure

“…Given this information and the results of Experiments 1 and 2, it is not surprising that Experiment 3 failed to find a difference between the experimental and control groups in the extinction test for conditioning to stimulus A. This failure is, however, still surprising from the point of view of the inverse hypothesis (for other failures, see Ayres & Bombace, 1982;Cheatle & Rudy, 1978;Vom Saal & Jenkins, 1970, Experiment 1).…”

Extinction of taste aversion does not eliminate taste potentiation of odor aversion in rats or color aversion in pigeons

“…The preconditioning exposures facilitated the formation of the odor-taste association (Durlach & Rescorla, 1980;Rescorla & Cunningham, 1978) and may even have been necessary for its occurrence, since acquisition of withincompound associations has been repeatedly shown to be disrupted by the subsequent occurrence of a US (Cheatle & Rudy, 1979;Holland, 1984;Rudy, 1984). Such preexposures have also been shown to weaken enhancement of the odor aversion (Palmerino , 1979;Palmerino et al, 1980), suggesting that they tend to reduce the probability of associative potentiation.…”

Posttrial effects of presenting vs. omitting expected shock USs in the conditioned suppression procedure: Concurrent measurement of barpress suppression and freezing

“…For example, Dickinson, Hall, and Mackintosh (1976) reported that omitting an expected US in the compound conditioning stage of the Kamin blocking procedure alleviated blocking to the target element (i.e., enhanced conditioning). Similarly, Cheatle and Rudy (1978) reported that if a neutral stimulus, X, was compounded with a preconditioned stimulus, A, X would gain second-order conditioned strength only if the US used to precondition A did not follow the AX compound. And Hall and Pearce (1982) reported that "associability" could be restored to a CS that had lost it through repeated pairings with a weak US by omitting the US on one or two trials before pairing the CS with a stronger US in the next stage.…”