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The authors used a touch screen-based visual-search task to investigate spatial integration in pigeons. First, pigeons were presented with a consistent spatial relationship between compound visual landmarks (LMs) A--X and B--Y, separately. Next, pigeons learned to find a hidden goal on the monitor in the presence of LMs A and B. The goal bore a consistent spatial relationship to LM A. but not to LM B. On nonreinforced probe tests, the peak and distribution of responses to LM X suggest that pigeons computed a novel X-goal spatial relationship on the basis of X--A and A--goal spatial vectors. Responses to LM Y, however, revealed no evidence of spatial integration. These results replicate and extend those of A. P. Blaisdell and R. G. Cook (2005) using an open-field task. Keywords: Spatial map, sensory preconditioning, integration, spatial vector, associative, pigeon

Two experiments with rats as subjects were conducted to investigate the associative structure of temporal control of conditioned inhibition through posttraining manipulation of the training excitor-unconditioned stimulus (US) temporal relationship. Experiment 1 found that following simultaneous Pavlovian inhibition training (i.e., A [right arrow] US/XA-no US) in which a conditioned stimulus (CS A) was established as a delay excitor, maximal inhibition was observed on a summation test when CS X was compounded with a delay transfer CS. Furthermore, posttraining shifts in the A-US temporal relationship from delay to trace resulted in maximal inhibition of a trace transfer CS. Experiment 2 found complementary results to Experiment 1 with an A-US posttraining shift from serial to simultaneous. These results suggest that temporal control of inhibition is mediated by the training excitor-US temporal relationship.

The information acquired in backward conditioning (i.e., outcome [right arrow] cue) was assessed in 3 Pavlovian lick-suppression experiments with water-deprived rats as subjects. Experiment 1 confirmed previous research that few outcome [right arrow] cue pairings made the cue into a conditioned excitor and additionally showed that massive posttraining extinction of the training context attenuated a backward-trained cue's excitatory value. Experiment 2 found that many outcome [right arrow] cue pairings made the cue into a conditioned inhibitor and that the same context manipulation attenuated this inhibitory value. Experiment 3 confirmed the observations of Experiments 1 and 2 and demonstrated that these effects of context extinction were specific to backward-trained cues conditioned in the extinguished context. These results are interpreted in terms of cue [right arrow] context and context [right arrow] outcome associations.

In 3 Pavlovian conditioned lick-suppression experiments, rats received overshadowing treatment with a footshock unconditioned stimulus such that Conditioned Stimulus (CS) A overshadowed CS X. Subjects that subsequently received CS X paired with an established signal for saccharin (CS B)exhibited less overshadowing of the X-footshock association than subjects that did not receive the X-B pairings (Experiment 1). Experiment 2 replicated this effect and controlled for some additional alternative accounts of the phenomenon. In Experiment 3, this recovery from overshadowing produced by counterconditioning CS X was attenuated if CS B was massively extinguished prior to counterconditioning. These results are more compatible with models of cue competition that emphasize differences in the expression of associations than those that emphasize differences in associative acquisition.

Three conditioned lick-suppression experiments with rats examined the effects of pretraining exposure to the conditioned stimulus (CS) on behavior indicative of conditioned inhibition. After CS-preexposure treatment, subjects received either Pavlovian conditioned inhibition training or explicitly unpaired inhibition training with the preexposed CS. The inhibitory status of the CS was then assessed with a retardation (Experiment 1) or a summation (Experiment 2) test. Experiment 3 controlled for the unconditioned stimulus-preexposure effect being a potential confound in Experiments 1 and 2. As predicted by the comparator hypothesis (R. R. Miller & L. D. Matzel, 1988), the CS-context association that developed during the CS-preexposure phase disrupted the expression of Pavlovian conditioned inhibition but not the expression of explicitly unpaired inhibition.

In 4 conditioned lick suppression experiments with rats, the combined effects of latent inhibition treatment followed by overshadowing treatment were assessed as a test of the comparator hypothesis's (R. R. Miller & L. D. Matzel, 1988) explanations of overshadowing and latent inhibition. Experiments 1 and 2 confirmed the prediction of the comparator hypothesis that combined latent inhibition and overshadowing treatments attenuate the response deficit produced by either treatment alone. Furthermore, consistent with the comparator hypothesis, posttraining changes in the associative status of the putative comparator stimulus altered responding to the target conditioned stimulus (Experiment 3), and switching contexts between latent inhibition and overshadowing treatments (Experiment 4) eliminated the interaction between the latent inhibition and overshadowing treatments.

Three conditioned lick suppression experiments explored the effects on overshadowing of the temporal relationships of two conditioned stimuli (CSs) with an unconditioned stimulus (US). Assuming overshadowing is maximal when the potential information conveyed by two competing CSs is equivalent, the temporal coding hypothesis predicts that greater overshadowing will be observed when the CSs share the same temporal relationship with the US. Rats were exposed to an overshadowing CS that had either a forward, simultaneous, or backward relationship to the US. The relationship of the overshadowed CSs to the US was either forward (Experiment 1), simultaneous (Experiment 2), or backward (Experiment 3). The greatest amount of overshadowing was observed when both CSs had the same temporal relationship to the US. The data are discussed within the framework of the temporal coding hypothesis and of alternative models of Pavlovian conditioning based on the informational hypothesis.

Two experiments using conditioned barpress suppression with rats explored an unblocking effect associated with qualitative change of the unconditioned stimulus between phases of a blocking paradigm. The unblocking effect refers to a lower amount of blocking, or failure to respond to a second conditioned stimulus, that occurred in association with a qualitative change in the unconditioned stimulus, compared to a group in which the unconditioned stimulus did not change.

The cognitive map has been taken as the standard model for how agents infer the most efficient route to a goal location. Alternatively, path integration – maintaining a homing vector during navigation – constitutes a primitive and presumably less‐flexible strategy than cognitive mapping because path integration relies primarily on vestibular stimuli and pace counting. The historical debate as to whether complex spatial navigation is ruled by associative learning or cognitive map mechanisms has been challenged by experimental difficulties in successfully neutralizing path integration. To our knowledge, there are only three studies that have succeeded in resolving this issue, all showing clear evidence of novel route taking, a behaviour outside the scope of traditional associative learning accounts. Nevertheless, there is no mechanistic explanation as to how animals perform novel route taking. We propose here a new model of spatial learning that combines path integration with higher‐order associative learning, and demonstrate how it can account for novel route taking without a cognitive map, thus resolving this long‐standing debate. We show how our higher‐order path integration (HOPI) model can explain spatial inferences, such as novel detours and shortcuts. Our analysis suggests that a phylogenetically ancient, vector‐based navigational strategy utilizing associative processes is powerful enough to support complex spatial inferences. [ABSTRACT FROM AUTHOR]

Beginning with Pavlov (1927), there has been great interest in how associative learning processes affect eating behavior. For instance, flavors can become preferred when paired with calories or, conversely, become aversive when paired with illness. This relationship between flavors and caloric or toxic outcomes has been investigated by a number of theorists. We studied the effect of daily consumption of a flavor that was either paired or unpaired with calories provided by sugar on body weight change and daily food consumption over a 21-day period. Over three experiments, we observed an unanticipated attenuation of weight gain following consumption of flavored liquid solutions, particularly when those solutions were non-caloric. However, we did not find any impact of consuming the flavored liquid solutions on appetite. Given differences in weight gain in the absence of differences in the amount of food consumed, we suggest that unconditioned metabolic responses are elicited to initially novel flavor stimuli, even if those flavors are not followed by caloric outcomes. Potential dieting interventions based on these findings are discussed as is how they inform our understanding of the balance between unconditioned and conditioned responses. [ABSTRACT FROM AUTHOR]