Journal of Experimental Psychology. Animal Learning and Cognition

In situations in which multiple predictors anticipate the presence or absence of an outcome, cues compete to anticipate the outcome, resulting in a loss of associative strength compared to control conditions without additional cues. Critically, there are multiple factors modulating the magnitude and direction of such competition, although in some scenarios the effect of these factors remains unexplored. We sought to assess whether the relative salience of the elements in a compound of cues modulates the magnitude of the overshadowing effect in human predictive learning...

Intermixed exposure to two similar stimuli, for example, AX and BX, improves subsequent discrimination between them compared to blocked exposure (the intermixed/blocked effect). Salience modulation models, developed mainly from research with nonhuman animals and exposure to widely spaced similar stimuli, explain this effect in terms of increased salience of the unique elements, A and B. Conversely, the results from experiments initially conducted with humans and exposure to close spaced similar stimuli have led to the suggestion that it is the development of well-unitized representations of unique elements that leads to better discrimination, leaving the unique elements with less effective salience...

We report here two large studies investigating the effects of an established transcranial direct current stimulation (tDCS) procedure on perceptual learning as indexed by the face inversion effect. Experiments 1a and 1b (n = 128) examined the harmful generalization from Thatcherized faces to normal faces by directly comparing the size of the inversion effect for normal faces when presented intermixed with Thatcherized faces (Experiment 1a) versus that obtained when normal faces were presented intermixed with checkerboards (Experiment 1b)...

Three experiments explored how training reinforcement schedules and context influence the elimination and recovery of human operant behavior. In Experiment 1, participants learned a discriminated operant response in Context A before the response was eliminated with extinction in Context B. They then received a final test in each context. Groups were trained with a discriminative stimulus that predicted a reinforced response on either every trial (continuous reinforcement [CRF]) or some of the trials (partial reinforcement [PRF])...

Four experiments explored the impact of focused-attention mindfulness training on human performance on free-operant schedules of reinforcement. In each experiment, human participants responded on a multiple random ratio (RR), random interval (RI) schedule. In all experiments, responding was higher on RR than RI schedules, despite equated rates of reinforcement. A 10-min focused-attention mindfulness intervention (focused attention) produced greater differentiation between schedules than relaxation training (Experiments 1, 2, and 4), or no intervention (Experiment 3)...

How do ants resolve conflicts between different sets of navigational cues during navigation? When two cue sets point to diametrically opposite directions, theories predict that animals should pick one set of cues or the other. Here we tested how nocturnal bull ants Myrmecia midas adjust their paths along established routes if route following does not lead to their entry into their nest. During testing, foragers were repeatedly placed back along their homeward route up to nine times, a procedure called rewinding...

In a long operant chamber, pigeons were trained to discriminate between 4-s and 12-s samples in a symbolic matching-to-sample task. Subsequently, delay and no-sample test trials were introduced. The location in the chamber in which the trial started and each comparison was presented varied across three experiments. Our main goals were to assess the effect of the delay and to compare preferences on delayed and no-sample trials. Both pigeons' preferences and their movement patterns were analyzed. In Experiments 1 and 3, pigeons learned to move immediately to the location where the correct comparison would be presented, allowing them to select a comparison at its onset and receive reinforcement...

In three experiments, rats were given experience of flavored solutions AX and BX, where A and B represent distinctive flavors and X a flavor common to both solutions. In one condition, AX and BX were presented on the same trial separated by a 5-min interval (intermixed preexposure). In another condition, each daily trial consisted of presentations of only AX or only BX (blocked preexposure). The properties acquired by stimulus X were then tested. Experiment 1 showed that after intermixed preexposure X was less able to interfere with a conditioned response established to a different flavor...

Inhibitory stimuli are slow to acquire excitatory properties when paired with the outcome in a retardation test. However, this pattern is also seen after simple nonreinforced exposure: latent inhibition. It is commonly assumed that retardation would be stronger for a conditioned inhibitor than for a latent inhibitor, but there is surprisingly little empirical evidence comparing the two in either animals or humans. Thus, retardation after inhibitory training could in principle be attributable entirely to latent inhibition...

Temporal information-processing is critical for adaptive behavior and goal-directed action. It is thus crucial to understand how the temporal distance between behaviorally relevant events is encoded to guide behavior. However, research on temporal representations has yielded mixed findings as to whether organisms utilize relative versus absolute judgments of time intervals. To address this fundamental question about the timing mechanism, we tested mice in a duration discrimination procedure in which they learned to correctly categorize tones of different durations as short or long...

The perception of temporal order can help infer the causal structure of the world. By investigating the perceptual signatures of audiovisual temporal order in rats, we demonstrate the importance of the protocol design for reliable order processing. Rats trained with both reinforced audiovisual trials and non-reinforced unisensory trials (two consecutive tones or flashes) learned the task surprisingly faster than rats trained with reinforced multisensory trials only. They also displayed signatures of temporal order perception, such as individual biases and sequential effects that are well described in humans, and impaired in clinical populations...

The Pavlovian-instrumental transfer (PIT) paradigm is widely used to assay the motivational influence of reward-predictive cues, reflected by their ability to invigorate instrumental behavior. Leading theories assume that a cue's motivational properties are tied to predicted reward value. We outline an alternative view that recognizes that reward-predictive cues may suppress rather than motivate instrumental behavior under certain conditions, an effect termed positive conditioned suppression. We posit that cues signaling imminent reward delivery tend to inhibit instrumental behavior, which is exploratory by nature, in order to facilitate efficient retrieval of the expected reward...

An important challenge for animal and artificial visual systems is separating the system's own motions from the movements of other animals or events. To examine this issue in birds, we conducted three experiments testing four pigeons in a go/no-go action discrimination. The pigeons discriminated whether a digital human model was exhibiting an extended series of articulated motions or one of a set of static poses from the same video. They were required to do so while the rendering camera's perspective changed continually during each trial's 20-s video presentation...

Six experiments with rats examined the nature of inhibition learned in an operant feature-negative (FN) discrimination. The results of prior experiments that examined instrumental extinction rather than FN learning suggest that inhibition can be very specific to the inhibited response. In Experiment 1, we trained lever-press and chain-pull responses in separate but parallel FN discriminations (AR1+, ABR1-, CR2+, and CDR2-) and then tested both inhibitors (B and D) with both responses. Of primary interest was the extent to which the inhibitors suppressed the response they were trained with (same-response inhibition) versus the other response (cross-response inhibition)...

The present article explored the fate of previously formed response-outcome associations when the relation between R and O was disrupted by arranging for O to occur independently of R. In each of three experiments response independent outcome delivery selectively reduced the R earning that O. Nevertheless, in Experiments 1 and 2, the R continued to show sensitivity to outcome devaluation, suggesting that the strength of the R-O association was undiminished by this treatment. These experiments used a two-lever, two-outcome design introducing the possibility that devaluation reflected the influence of specific Pavlovian lever-outcome associations...

Considerable discussion has concerned the role of context in conditional discrimination learning. Some authors have proposed that contexts might operate hierarchically on CS-US associations, whereas others have proposed that the context plus the CS might be processed configurally. In the present article, we report the results of two experiments that assessed the role of context on pigeons' conditional discrimination learning. In Experiment 1, we found that our pigeons' responding was inconsistent with hierarchical processing; instead, they may have either relied on local features or on configural compounds comprising the context and the discriminative stimulus presented on each trial...

Negative patterning tasks are a key tool to unveil the mechanisms by which stimulus representations are acquired-a central concern in Robert Rescorla's research. In these tasks, target stimuli are reinforced when presented individually (A+/B+) but not when presented in compound (AB-). The discrimination of single stimuli from their compound presentation is a challenge for theories of associative learning, because it cannot be explained by the simple accrual of associative strength. The present study examined the conditions under which mice learn this part-whole discrimination in olfactory stimuli using a novel instrumental methodology...

Conditioned responding is sensitive to reinforcement rate. This rate-sensitivity is impaired in genetically modified mice that lack the GluA1 subunit of the AMPA receptor. A time-dependent application of the Rescorla-Wagner learning rule can be used to derive an account of rate-sensitivity by reflecting the balance of excitatory and inhibitory associative strength over time. By applying this analysis, the impairment in GluA1 knockout mice may be explained by reduced sensitivity to negative prediction error and thus, impaired inhibitory learning, such that excitatory associative strength is not reduced during the nonreinforced periods of a conditioned stimulus...

Associative accounts of category learning have been, for the most part, abandoned in favor of cognitive explanations (e.g., similarity, explicit rules). In the current work, we implement an Adaptive Linear Filter (ALF) closely related to the Rescorla and Wagner learning rule, and use it to tackle three learning tasks that pose challenges to an associative view of category learning. Across three computational simulations, we show that the ALF is in fact able to make the predictions that seemed problematic. Notably, in our simulations we use exactly the same model and specifications, attesting to the generality of our account...

The field of associative learning theory was forever changed by the contributions of Robert A. Rescorla. He created an organizational structure that gave us a framework for thinking about the key questions surrounding learning theory: what are the conditions that produce learning?, what is the content of that learning?, and how is that learning expressed in performance? He gave us beautifully sophisticated experimental designs that tackled deep theoretical problems in experimentally clever and elegant ways...