Associative interference with taste aversions after contextual discrimination learning

In two experiments, rats were first given discriminative training with two distinctive contexts, such that a flavor was paired with lithium chloride (LiCl) in one context, alternating with presentations of the flavor alone in another context. Contextual control of the fluid ingestion was observed in that rats reduced the fluid intake in the LiCl-paired context but drank the solution in the context never paired with lithium. Having learned this discrimination, the rats were now given a second flavor in their home cage before being injected with LiCl and transferred to the previously lithium-paired context. In Experiment 1, the acquisition of an aversion to the novel flavor was blocked when this flavor and the contextual cues are conditioned as a compound. In Experiment 2, the blocking effect and the conditional control over fluid consumption were abolished when the associative strength of the LiCl-paired context had been extinguished by exposing the animals to water in the contexts after discriminative training. These results are interpreted as evidence that context dependency of conditioned taste aversions is mediated by a summative effect of the context–LiCl and flavor–LiCl associations.     

Response selection in paired-associate learning

Ss were presented pairs of items on study cycles; on test cycles Ss were presented the stimulus items and required either to recall the correct response or to indicate the correct response from three alternatives. It was demonstrated that Ss who chose the correct responses from the alternatives tended to select from both stimulus and response compounds so that the association was between stimulus and response components. The amount of selection from the response compounds was comparable to that from the stimulus compounds.     

Enactive imagery in paired-associate learning

Three experiments were conducted to study the effects of enactive imagery (EI) on associative learning. In Experiment I, groups of Ss rated 226 verbs on EI and frequency. In Experiments II and III, Ss learned a 24- and a 16-item list, respectively. The lists consisted of the four possible stimulus-response combinations of high (H) and low (L) EI verb pairs: H-H, H-L, L-H, L-L. In both experiments, EI was found to be a significant factor on the stimulus side, performance being superior when the stimulus was of high EI. In Experiment III, the response EI main effect and the Stimulus by Response EI interaction were also found to be significant. The results indicated that like the imagery evoked by nouns, the EI evoked by verbs facilitates learning.     

Second responses in paired-associate learning

Mathematical models of memory can be evaluated using a continuous paired-associate learning paradigm in which a second response is requested immediately following an error. This procedure provides discriminability among the models on the basis of the relationship between the first- and second-response error probabilities. Theoretical predictions are derived for a variety of models, including finite-state and noncontingent operator models, formulations based on the theory of signal detectability, the multicomponent memory model of Bower (1967b), and the long- and short-term model of Atkinson and Shiffrin (1968). None of these is unequivocally acceptable, and many are decisively rejected by the data of a single-trial experiment. The most satisfactory models are the multicomponent model and the Atkinson and Shiffrin model, both of which assume a greater degree of internal structure than the rejected models. It appears that internal structure of this sort will be a necessary part of any satisfactory model of second responses.