Summation is the usual result in composition procedures with excitatory stimuli. However, summation is difficult to obtain in autoshaping with pigeons. The problems with this preparation have been related to the stimuli used: combinations of intramodal conditioned stimuli (CSs). During the perceptual processing of this type of stimuli, some mutual…

The present research explored the effects of restraint stress on two situations involving incentive downshift: consummatory successive negative contrast (cSNC) and extinction of escape behavior in the Barnes maze. First, Experiment 1 confirmed that the restraint stress procedure used in these experiments increased levels of circulating…

Four experiments with rats examined Pavlovian incubation, in which responding increases when Pavlovian conditioning is followed by a testing delay. In a within-subjects design, Experiment 1 first showed that when a single food pellet unconditioned stimulus (US) signaled the delivery of three additional pellets, responding after the single US was…

Recent studies have demonstrated that the expectation of reward delivery has an inverse relationship with operant behavioral variation (e.g., Stahlman, Roberts, & Blaisdell, 2010). Research thus far has largely focused on one aspect of reinforcement--the likelihood of food delivery. In two experiments with pigeons, we examined the effect of two…

In resurgence, an operant behavior that has undergone extinction can return ("resurge") when a second operant that has replaced it itself undergoes extinction. The phenomenon may provide insight into relapse that may occur after incentive or contingency management therapies in humans. Three experiments with rats examined the impact of several…

Efforts to develop animal models of memory are critical for understanding the neural substrate of memory. Memory is essential for daily life and enables information to be stored and retrieved after seconds to years. The ability to remember episodes from the past is thought to be related to the ability to plan for the future. Here we focus on a…

When trained to locate a hidden platform in a T-maze moved between two positions, rats appear to adopt a conditional strategy based on start point discrimination. To determine if location cues or orientation cues at the start point underlie this discrimination, separate groups of rats were trained on two place problems, each with unique start…

Contextual specificity of Latent Inhibition (LI) has been demonstrated using an ample range of experimental procedures. Context dependence has not been consistently obtained, however, when LI has been induced using a Conditioned Taste Aversion (CTA) procedure. This paper presents two experiments designed to analyze whether the context plays the…

Previous work has shown that children are able to make a spatial inference about adjacent locations that have only been experienced indirectly (Hazen, Lockman, & Pick, 1978). We sought to replicate this finding in rats, on a conceptually analogous task. In a first experiment, rats (n = 8) were given 110 training trials on a task in which they…

In this paper we discuss some literature relating to episodic memory, future episodic thinking and mental time travel in humans and non-human animals. We discuss the concept of mental time travel and argue that the concept relies on subjective phenomena such as consciousness and on this basis is not useful when studying episodic memory and future…

The olfactory span task (OST) uses an incrementing non-matching to sample procedure such that the number of stimuli to remember increases during the session. The number of consecutive correct responses (span length) and percent correct as a function of the memory load have been viewed as defining rodent working memory capacity limitations in…

Two studies using an ABA design examined the Extinction and renewal of conditioned barpress suppression. Following lights-off and foot shock pairings in Context A, rats were placed in Context B and were given either a standard counterconditioning procedure where the lights-off CS was paired with a novel food US delivered freely or a modified…

Rats were trained in a symbolic delayed matching-to-sample task to discriminate sample stimuli that consisted of the presence of food or the absence of food. Asymmetrical sample training was provided in which one group was initially trained with only the food sample and the other group was initially trained with only the no-food sample. In…

Evidence concerning the possibility of mental time travel into the future by animals was reviewed. Both experimental laboratory studies and field observations were considered. Paradigms for the study of future anticipation and planning included inhibition of consumption of current food contingent on future receipt of either a larger quantity or…

Prospective memory involves the encoding, retention, and implementation of an intended future action. Although humans show many forms of prospective memory, less is known about the future oriented processes of nonhuman animals, or their ability to use prospective memory. In this experiment, a chimpanzee named Panzee, who had learned to associate…