The negative-contrast effect occurs when animals that are shifted from large to small reward temporarily drop below small reward control groups. The basic question asked here in three experiments was whether animals tested under a specific drive level will behave as though they expect a reward magnitude previously received, depending on the reward…

Assesses the validity of physiological versus learning interpretations of illness-preexposure effects. (Author/RK)

If animals receive inescapable electric shocks, their subsequent avoidance-escape learning is poor. This phenomenon, which can be called "the interference effect", was studied in four experiments. (Editor)

Investigates how the inhibition and latency-reduction effects interact with each other and how they change with changes in the intensity of the startle-eliciting stimulus. (Author/RK)

Experimenters in the past have reported that when insulin is used as the unconditioned stimulus (US), rats will learn an aversion to a sodium chloride but not a sucrose solution, whereas with formalin as the US, they will learn an aversion to a sucrose but not a saline solution. The present experiments failed to confirm these findings. (Editor)

These experiments investigate the degree to which neophobia, the reluctance to consume novel food, can be modified by toxicosis, the conditions under which the contingency between ingestion and illness enhances neophobia, and the manner in which previously learned aversions mediate subsequent enhanced neophobia. (Author/RK)

These experiments investigate situations in which a negative correlation involves a 24 hour delay between the occurrence of a conditioned stimulus and an unconditioned stimulus; they also investigate the mechanism by which any inhibition so produced might occur. (Author/RK)

The research reported here was directed at evaluating whether or not the effectiveness of a Pavlovian unconditioned stimulus (US) in promoting associative learning is reduced if the US is shortly preceded by another occurrence of the same US. (Author)

Several experiments tested the occurrence of the "Kamin effect", i.e., the deficit in performance of an incompletely learned avoidance task, in terms of discrimination (choice) behavior by rats. (Editor/RK)

Repeated, isolated presentations of a stimulus typically reduce the subsequent ability of that cue to become an effective conditioned stimulus. This phenomenon is known as the latent inhibition effect. Four experiments investigate this effect. (Editor/RK)

These experiments attempt to optimize the possibility of demonstrating blocking in a taste-aversion paradigm and to elucidate the conditions under which this interference occurs. (Author/RK)

To complement investigations of the direct effects of lithium toxicosis on consummatory behavior, these experiments were designed to determine the aftereffects on drinking of exposure to a conditioned stimulus previously paired with lithium. (Author/RK)

In four different experiments, brief illumination of a localized visual stimulus was followed by grain presentation unless the pigeon approached the light. Results indicate that although response-reinforcer relations do play a role, stimulus-reinforcer contingencies are the dominant factor in establishing and maintaining approaches to the…

Three experiments were performed to test the assertion that attractiveness of novel or complex stimuli has confounded experiments on the relative importance of S+ and S- in discrete-trial discrimination. (Editor)