Journal of Experimental Psychology: Animal Behavior Processes

Both trace and delay conditioned eyeblink responding can be dissociated from outcome expectancy.
Squire and colleagues have proposed that trace and delay eyeblink conditioning are fundamentally different kinds of learning: trace conditioning requires acquisition of a conscious declarative memory for the stimulus contingencies whereas delay conditioning does not. Declarative memory in trace conditioning is thought to generate conditioned responding through the activation of a conscious expectancy for when the unconditioned stimulus (US) is going to occur. Perruchet (1985) has previously shown that in a 50% partial reinforcement design it is possible to dissociate single cue delay eyeblink conditioning from conscious expectancy for the US by examining performance over runs of reinforced and nonreinforced trials. Clark, Manns, and Squire (2001) claim that this dissociation does not occur in trace eyeblink conditioning. In the present experiment we examined the Perruchet effect for short, moderate, and long trace intervals (600, 1000, and 1400 ms) and for the equivalent interstimulus intervals (ISIs) in a delay conditioning procedure. We found evidence for a dissociation of eyeblink CRs and US expectancy over runs regardless of whether there was a delay or a trace arrangement of cues. The reasons for the Perruchet effect are still unclear, but the present data suggest that it does not depend on a separate nondeclarative system of the type proposed by Squire and colleagues. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Human sensitivity to the magnitude and probability of a continuous causal relation in a video game.
Continuous causation, in which incremental changes in one variable cause incremental changes in another, has received little attention in the causal judgment literature. A video game was adapted for the study of continuous causality in order to examine the novel cues to causality that are present in these paradigms. The spatial proximity of an object to an “enemy detector” produced auditory responses as a function of the object's proximity. Participants' behavior was a function of the range of the effect's auditory sensitivity and the moment-to-moment likelihood of detection. This new paradigm provides a rich platform for examining the cues to causation encountered in the learning of continuous causal relations. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Quantity judgments of auditory and visual stimuli by chimpanzees (Pan troglodytes).
Many species can choose between two visual sets of stimuli on the basis of quantity. This is true when sets are both visible, or are presented one set at a time or even one item at a time. However, we know comparatively little about how well nonhuman animals can compare auditory quantities. Here, three chimpanzees ( Pan troglodytes ) chose between two sets of food items when they only heard each item fall into different containers rather than seeing those items. This method prevented the chimpanzees from summing the amount of visible food they saw because there were no visual cues. Chimpanzees performed well, and their performance matched that of previous experiments with regard to obeying Weber's law. They also performed well with comparisons between a sequentially presented auditory set and a fully visible set, demonstrating that duration of presentation was not being used as a cue. In addition, they accommodated empty sets into these judgments, although not perfectly. Thus, chimpanzees can judge auditory quantities in flexible ways that show many similarities to how they compare visual quantities. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Time-sharing in rats: Effect of distracter intensity and discriminability.
Interruptions (gaps) and unfamiliar events (distracters) during a timed signal delay the timed response of humans and other animals. To explore this phenomenon, we manipulate the intensity of auditory distracters (Experiment 1), and we dissociate the role of distracter intensity, distracter similarity with the intertrial interval, and dissimilarity from the timed auditory signal (Experiment 2). When the intertrial interval and the timed signal were silent, the delay in response after an auditory distracter increased with its intensity: Rats ignored (ran through) a 40-dB distracter, stopped timing during a 75-dB distracter, and reset after a 100-dB distracter. However, when timing was signaled by a 70-dB noise, rats reset both for 40- and 100-dB distracters, stopped for both 55- and 85-dB distracters, and run for the 70-dB distracter. Data are accounted for by a time-sharing model assuming 2 concurrent processes—time accumulation and memory decay controlled by the discriminability of the interrupting event—whose interplay results in a continuum of responses, from run to reset. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The role of contextual associations in producing the partial reinforcement acquisition deficit.
Three conditioned suppression experiments with rats as subjects assessed the contributions of the conditioned stimulus (CS)–context and context–unconditioned stimulus (US) associations to the degraded stimulus control by the CS that is observed following partial reinforcement relative to continuous reinforcement training. In Experiment 1, posttraining associative deflation (i.e., extinction) of the training context after partial reinforcement restored responding to a level comparable to the one produced by continuous reinforcement. In Experiment 2, posttraining associative inflation of the context (achieved by administering unsignaled outcome presentations in the context) enhanced the detrimental effect of partial reinforcement. Experiment 3 found that the training context must be an effective competitor to produce the partial reinforcement acquisition deficit. When the context was down-modulated, the target regained behavioral control thereby demonstrating higher-order retrospective revaluation. The results are discussed in terms of retrospective revaluation, and are used to contrast the predictions of a performance-focused model with those of an acquisition-focused model. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Associative status of the training context determines the effectiveness of compound extinction.
Studies of extinction of a target cue in compound with another excitor have produced evidence of both deepened and attenuated extinction relative to elemental extinction. The present experiments sought to resolve this discrepancy by assessing the effect of the extinction context-unconditioned stimulus (US) association on compound extinction. In an ABC renewal situation with rats, Experiment 1 replicated the observation that enhanced extinction (i.e., reduced conditioned suppression) occurs as a result of nonreinforcement in compound with a concurrent excitor. In Experiment 2, inflation of the extinction context-US association through unsignaled, intertrial US presentations reversed the effect of a concurrent excitor (i.e., extinction with a concurrent excitor was less effective than elemental extinction). Experiment 3 compared compound extinction and second-order conditioning with respect to the effect of context inflation, and produced results incompatible with the view that second-order conditioning contributed to the results of Experiment 2. In Experiment 4, a concurrent excitor enhanced extinction in ABC renewal and attenuated extinction in AAC renewal. The present results suggest that the effect of a concurrent excitor during extinction depends on the strength of the extinction context-US association, thereby confirming predictions of the sometimes -competing retrieval model of associative acquisition and extinction. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Correction to Jones and Haselgrove (2011).
Reports an error in "Overshadowing and associability change" by Peter M. Jones and Mark Haselgrove ( Journal of Experimental Psychology: Animal Behavior Processes , 2011[Jul], Vol 37[3], 287-299). The number of sessions and trials given for Experiment 1 is incorrect. The correct number of sessions and trials are presented in the erratum. (The following abstract of the original article appeared in record 2011-07615-001.) Three appetitive Pavlovian conditioning experiments with rats examined the associability of stimuli A and B that had a history of compound conditioning (AB+), relative to stimuli X and Y that had a history of conditioning in isolation (X+, Y+). Following this training, Experiment 1 revealed that conditioned responding was higher to X and Y than to A and B (overshadowing). In a subsequent AY+, AX−, BY− test discrimination, the AY/BY discrimination was solved more readily than the AY/AX discrimination. In Experiment 2, following AB+, X+, Y+ training, A and Y were presented as a compound and signaled the availability of reinforcement upon the performance of an instrumental response. Test trials in which A and Y were presented alone, and in extinction, revealed that A acquired greater control of instrumental responding than Y. Experiment 3 revealed that following AB+, X+, Y+ training, A and B served as more effective discriminative stimuli for instrumental responding than X and Y. Overall, these results imply that the associability of stimuli conditioned in compound is higher than stimuli conditioned in isolation. These results are discussed in terms of attentional theories of associative learning. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Salience modulation in serial preexposure: Implications for perceptual learning.
In three experiments rats were given serial preexposure to two flavor stimuli. In Experiment 1, some animals were given exposure to AX followed by the presentation of BX, a forward schedule; the others were given backward preexposure (BX→AX). Conditioning and test trials with the A element showed that salience or effectiveness of A was better protected in the forward than in the backward condition. Experiments 2 and 3 assessed the relevance of this salience modulation mechanism for perceptual learning. In these experiments, generalization of a conditioned aversion from AX to BX was reduced in the forward (but not in the backward) condition only after prolonged exposure, indicating that the establishment of an inhibitory link from B to A is required for successful discrimination. However, generalization to a novel compound stimulus, NX, was reduced in the forward group both after short and long preexposure, suggesting the existence of salience modulation processes that work in parallel with associative inhibition. These results seem to support the existence of a salience modulation mechanism that seems to be beyond the scope of current theories of perceptual learning. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Indirect object recognition: Evidence for associative processes in recognition memory.
Rats' exploration of stimulus P (e.g., a domestic object) is reduced following either its direct exposure or its indirect exposure and is taken to indicate recognition memory. Procedures for demonstrating indirect object recognition involve an initial presentation of object P with stimulus X (and of an object Q with stimulus Y). On test, stimulus X is presented with objects P and Q and rats' exploration of Q exceeds their exploration of P. One interpretation here is that the presentation of stimulus X on test associatively activates the memory of object P, which diminishes exploration of P relative to Q. It is possible, instead, that performance is simply the result of a novel pattern of stimulation generated by the unfamiliar combination of X and Q. The authors modified this procedure to reduce the likelihood of such a process. Their procedure involved first the presentation of PX and QY before the presentation of stimulus X alone. During the test that followed, objects P and Q were presented but stimulus X was removed. The authors found that exploration of Q remained greater than that of P despite these modifications and discuss some theoretical implications of indirect, associative processes in recognition memory. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Classical conditioning mechanisms can differentiate between seeing and doing in rats.
We show that the attentional-associative SLG model of classical conditioning, based on the 1996 research of Schmajuk, Lam, and Gray, correctly describes experimental results regarded as evidence of causal learning in rats: (a) interventions attenuate responding following common-cause training but do not interfere on subsequent responding during observation, and (b) interventions do not affect responding after direct-cause training or (c) causal-chain training. According to the model, responding to the weakly attended test stimulus is strongly inhibited by the intervention in the common-cause case. Instead, in the direct-cause and causal-chain cases, the strongly attended test stimulus becomes inhibitory, thereby overshadowing the inhibitory effect of interventions. Most importantly, the model predicted that with relatively few test trials (a) the 2008 results of Experiment 3 by Leising, Wong, Waldmann, and Blaisdell should be similar to those of Dwyer, Starns, and Honey's 2009 Experiment 1, showing that interventions equally affect responding after common-cause and direct-cause training; and (b) the 2006 results of Experiment 2a by Blaisdell, Sawa, Leising, and Waldmann should be similar to those of Dwyer, Starns, and Honey's 2009 Experiment 2, showing that interventions equally affect responding after common-cause and causal-chain training. When those data were made available to us, we confirmed those predictions. In agreement with the SLG associative model, but not with causal model theory, this evidence supports the notion that the attenuation of responding by interventions only following common-cause training is the consequence of well-known learning processes—latent inhibition, sensory preconditioning, conditioned inhibition, protection from extinction, and overshadowing. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Evidence for a magnitude effect in temporal discounting with pigeons.
A magnitude effect in human intertemporal choice is well established—larger rewards or outcomes are discounted over time at a lower rate than are smaller rewards. However, many recent studies have failed to find a corresponding effect in nonhuman animals. Here we report a magnitude effect in temporal discounting for pigeons' choices involving a tradeoff between reward delay and amount. Pigeons chose between a small reward (1-s access to food) after a 2-s delay, and a large reward (4.5-s access to food) after a 28-s delay. Across conditions, the delays to the small and large rewards were increased or decreased, respectively. Temporal discounting functions obtained through a value-estimation procedure showed clear evidence of a magnitude effect: The value of the large reward decreased more slowly with increasing delay than the value of the small reward. We linked this result to a nonlinear relationship between choice and the delays associated with the small and large rewards. The nonlinearity was contrary to the generalized matching law but was predicted by the contextual choice model. Our results confirm the existence of a magnitude effect in nonhuman temporal discounting, showing that this adaptation is not unique to humans. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

Journal of Experimental Psychology: Animal Behavior Processes - Vol 38, Iss 1