Journal of Experimental Psychology-Animal Learning and Cognition最新文献

We investigated how differential payoffs affect temporal discrimination. In a temporal bisection task, pigeons learned to choose one key after a short sample and another key after a long sample. When presented with a range of intermediate samples they produced a Gaussian psychometric function characterized by a location (bias) parameter and a scale (sensitivity) parameter. When one key yielded more reinforcers than the other, the location parameter changed, with the pigeons biasing their choices toward the richer key. We then reproduced the bisection task in a long operant chamber, with choice keys far apart, and tracked the pigeons' motion patterns during the sample. These patterns were highly stereotypical-on the long sample trials, the pigeons approached the short key at sample onset, stayed there for a while, and then departed to the long key. The distribution of departure times also was biased when the payoff probabilities differed. Moreover, it is likely that temporal control decreased while control by location increased. No evidence was found of changes in temporal sensitivity. The results are consistent with models of timing that take into account bias effects and competition of stimulus control. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Two experiments investigated an evaluative transfer from actions producing pleasant and unpleasant outcomes to novel stimuli that were assigned to those actions in a subsequent stimulus-response task. Results showed that a fictitious social group was liked more when this group was assigned to the action previously associated with pleasant outcomes relative to the other action. This evaluative transfer from operant contingencies was observed although the actions did not generate outcomes during the stimulus-action pairing. It is concluded that operant contingencies can be used for preference construction because they specify the existence of a relation between specific actions and particular valenced events. Implications for mental process theories of preference formation and motivated perception are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Four experiments compared the extinction of responding to a continuously reinforced (CRf) conditioned stimulus (conditional stimulus [CS]) consistently reinforced on every trial, with extinction of responding to a partially reinforced (PRf) CS that had been inconsistently reinforced. To equate the acquisition of responding between the two CSs, the average duration of the CRf CS was extended so that it scheduled the same overall rate of reinforcement per unit time as the PRf CS. Experiment 1 used a within-subjects design to compare the rates of extinction for a 10-s PRf CS reinforced on 33% of trials versus a 30-s CRf CS. Experiment 2 made the same comparison but using a between-subjects design. Experiment 3 compared extinction in a group trained with a 10-s PRf CS reinforced on 20% of trials and a group trained with a 50-s CRf CS. Experiment 4 compared the rates of extinction following two partial reinforcement schedules: a 10-s PRf CS reinforced on 33% of trial versus a 20-s CRf CS reinforced on 66% of trials. In each experiment, responding took longer to extinguish for the CS that scheduled a lower per-trial probability of reinforcement. Modeling of individual extinction curves using Weibull functions indicated that the latency to initiate extinction was directly related to the per-trial probability of reinforcement learned during acquisition. For example, compared with training with a CRf CS, rats reinforced on 33% of trials took approximately 3 times as many trials to initiate extinction, and rats reinforced on 20% of trials took 5 times as many trials to initiate extinction. These results provide support for trial-based accounts of extinction (e.g., Capaldi & Deutsch, 1967), whereby rats learn about the expected number of trials per reinforcer, and extinction depends on the number of expected reinforcers that have been omitted rather than on the number of extinction trials per se. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Conditioned inhibition is a Pavlovian learning phenomenon in which a stimulus that predicts the absence of an otherwise expected outcome comes to control an organism's responding. Such responding usually manifests as a tendency that opposes that of a stimulus that predicts the outcome, also known as a conditioned excitor. Some learning theorists have expressed concerns about the validity and usefulness of conditioned inhibition as a concept; claims that may have negatively affected the reputation of this research area. This article offers a contemporary review of critiques of and controversies over conditioned inhibition and of arguments advanced in its defense. Some of these disputes have been reported in previous reviews, but here we have sought to compile the most representative among them. We also propose new arguments that answer some of those critiques. We then address the most prominent theoretical accounts of conditioned inhibition, identifying commonalities and differences among some of them. Finally, we review recent studies of conditioned inhibition. Some of the new findings contribute to rejecting early critiques of conditioned inhibition and others further elucidate the nature of this phenomenon. A new set of studies suggests that a deficit in conditioned inhibition characterizes some psychiatric conditions, illustrating its translational importance. We believe that new generations of researchers will benefit from being aware of past controversies and how they may have shaped the current conception of conditioned inhibition. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The blocking phenomenon is one of the most enduring issues in the study of learning. Numerous explanations have been proposed, which fall into two main categories. An associative analysis states that, following A+/AX+ training, Cue A prevents an associative link from forming between X and the outcome. In contrast, an inferential explanation is that A+/AX+ training does not permit an inference that X causes the outcome. More specifically, the trials on which X is presented (AX+) are often argued to be uninformative with respect to the causal status of X because the outcome would have resulted on AX trials whether X was causal or not. If participants are uncertain about X, their ratings on test might be particularly sensitive to the overall base rate of the outcome. That is, a blocked cue, about which one is uncertain, should be rated as a more likely cause when most cues lead to the outcome than when most cues do not. This hypothesis was supported in 2 experiments. Experiment 1 used an overshadowing control and Experiment 2 used an uncorrelated control (to demonstrate a redundancy effect). Variations in the ratings of the blocked cue as a result of manipulating the outcome base rate can be explained if participants are uncertain about the status of the blocked cue. Experiment 3 showed that participants are uncertain about blocked cues by using a direct self-report measure of certainty. These data are consistent with the inferential account, but are more challenging for the associative analysis. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

A defining feature of Pavlovian conditioning is that the unconditioned stimulus (US) is delivered whether or not the animal performs a conditioned response (CR). This has lead to the question: Does CR performance play any role in conditioning? Between the 1930s and 1970s, a consensus emerged that CR acquisition is driven by CS-US (CS, conditioned stimulus) experiences, and that CRs play a minimal role, if any. Here we revisit the question and present 2 new quantitative methods to evaluate whether CRs influence the course of learning. Our results suggest that CRs play an important role in Pavlovian acquisition, in such paradigms as rabbit eye blink conditioning, pigeon autoshaped key pecking, and rat autoshaped lever pressing and magazine entry. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The current article concerns human outcome-selective Pavlovian-instrumental transfer (PIT), where Pavlovian cues selectively invigorate instrumental responses that predict common rewarding outcomes. Several recent experiments have observed PIT effects that were insensitive to outcome devaluation manipulations, which has been taken as evidence of an automatic "associative" mechanism. Other similar studies observed PIT effects that were sensitive to devaluation, which suggests a more controlled, goal-directed process. Studies supporting the automatic approach have been criticized for using a biased baseline, whereas studies supporting the goal-directed approach have been criticized for priming multiple outcomes at test. The current experiment addressed both of these issues. Participants first learned to perform two instrumental responses to earn two outcomes each (R1-O1/O3, R2-O2/O4), before four Pavlovian stimuli (S1-S4) were trained to predict each outcome. One outcome that was paired with each instrumental response (O3 and O4) was then devalued, so that baseline response choice at test would be balanced. Instrumental responding was then assessed in the presence of each individual Pavlovian stimulus, so that only one outcome was primed per trial. PIT effects were observed for the valued outcomes (ts > 3.96, ps < .001) but not for the devalued outcomes (F < 1, Bayes Factor10 = .29). Hence, when baseline response choice was equated and only one outcome was primed per test trial, PIT was sensitive to outcome devaluation. The data therefore support goal-directed models of PIT. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Much empirical work and theoretical discussion in the associative learning literature has focused on when and how a cue changes in its associability. A series of new findings in human learning preparations (collectively referred to as the "outcome predictability" effect) appear to show that outcomes vary in their capacity to enter into novel associations as a product of their associative history. This effect is reminiscent of how cues change in associability as a consequence of their reinforcement history. We review the new findings within a broader associative literature that has previously investigated how conditioning can modify the effectiveness of outcome events to motivate new learning. A variety of explanations arising from this review are then critically considered. The article concludes by identifying novel questions brought into focus by the outcome predictability effect. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Successive negative contrast (SNC) involves a disruption of behavior when the paired reward is unexpectedly reduced from a large to a small amount, relative to a control always receiving the small amount. Five experiments with rats explored SNC in the Pavlovian autoshaping procedure in which a retractable lever is paired with the delivery of food pellets. In Experiment 1, a 12-to-2 pellet downshift either early in training (after 3 sessions) or late in training (after 20 sessions) yielded no significant evidence of SNC either in terms of lever pressing or goal entries. Experiment 2 showed that presession feeding (another form of reward devaluation) suppressed lever pressing in nonreinforced tests early in training. However, no statistical evidence of lever pressing suppression was found late in training. Presession feeding also suppressed lever pressing late in training if the test session included reinforcements. Experiment 3, using reward downshift, showed that adding a nontarget lever produced no statistical evidence of response suppression to the target lever during the downshift. Lever pressing to the target lever increased and goal entries tended to decrease after a 12-to-2 pellet downshift. Using a within-subject design and two target levers with distinct reward values (Experiment 4), reward downshift produced evidence of lever pressing enhancement in single-lever trials, but lever pressing suppression and a switch in preference to the unshifted lever in nonreinforced free-choice trials. Experiment 5 replicated these within-subject SNC effects, but found only modest evidence for a successive positive contrast effect in free-choice behavior. These results suggest that autoshaping in rats may induce response invigoration in forced-choice situations, but response suppression in free-choice situations. (PsycINFO Database Record (c) 2018 APA, all rights reserved).