Journal of the experimental analysis of behavior最新文献

Research with nonhumans and human children has questioned the notion of the strengthening properties of reinforcers when choices are controlled by what reinforcers signal about upcoming events. We extended this work by developing and evaluating an automated task to evaluate the discriminative versus strengthening effects of reinforcers with two children of typical development (Experiment 1) and 18 university students (Experiments 2 and 3). Participants responded by touching one of two concurrently available images on a touchscreen. Across conditions, the probability that the next reinforcer would be delivered at the same location as the immediately preceding reinforced response varied with probabilities of .10 (switch), .50 (control), and .90 (stay). Both children and students responded according to the arranged reinforcer probabilities of the next reinforcer instead of where the most recent reinforcer had been delivered. The present findings add to the body of work suggesting that reinforcers serve a discriminative function, and we use a quantitative model of reinforcer misallocation to account for choices being imperfectly controlled by contingencies.

Traditionally, the experimental analysis of behavior has relied on the single discrete response paradigm (e.g., key pecks, lever presses, screen clicks) to identify behavioral patterns. However, the development and availability of new technology allow researchers to move beyond this paradigm and use other features to detect schedules. Thus, our study used spatiotemporal data to compare the accuracy of four machine learning algorithms (i.e., logistic regression, support vector classifiers, random forests, and artificial neural networks) in detecting the presence and the components of time-based schedules in 12 rats involved in a behavioral experiment. Using spatiotemporal data, the algorithms accurately identified the presence or absence of programmed schedules and correctly differentiated between fixed- and variable-space schedules. That said, our analyses failed to identify an algorithm to discriminate fixed-time from variable-time schedules. Furthermore, none of the algorithms performed systematically better than the others. Our findings provide preliminary support for the utility of using spatiotemporal data with machine learning to detect stimulus schedules.

Reinstatement refers to the recurrence of extinguished behavior following response-dependent or -independent exposure to stimuli such as reinforcers, stressors, or reinforcer-correlated cues. Despite broad research on this form of behavioral relapse, little is known about reinstatement of behavior previously maintained by negative reinforcement. The present study explored reinstatement of negatively reinforced behavior with rats under a timeout-from-avoidance procedure. First, responses to the timeout lever could produce 2-min timeouts from a free-operant avoidance schedule wherein shocks could be postponed by pressing an avoidance lever. Then, timeout responding was extinguished by withholding timeouts while the avoidance response continued to postpone shocks. Finally, response-independent timeouts were delivered as the avoidance schedule remained unchanged. The results showed that extinguished timeout responding was reinstated in most subjects following the delivery of response-independent timeouts. These findings expand the generality of the reinstatement effect reported with positive reinforcement to another functional class of behavior and provide an animal model to extend research on behavioral relapse.

Two distinctive nonverbal procedures match verbal transitive syllogisms: (1) transitive inference (TI), often presented as an analogy to verbal transitive inference, and (2) transitivity (TR), commonly discussed in the context of emergent relations and stimulus equivalence. Although the tasks are often used interchangeably in human studies, it remains unclear whether they rely on similar behavioral strategies or engage the same brain areas in nonhuman animals. This review examines similarities and differences between the TI task and the TR task, concluding that existing research does not clearly indicate whether they share a common cognitive domain. Additionally, the review outlines future research directions (investigating task difficulty, exploring underlying neural circuitry, examining individual behavioral differences, and developing a unified computational model) that will be essential for clarifying this relationship.

The likelihood of forming equivalence classes was influenced by the format used in sorting tests and by four different test criteria applied to the same data set.  After 30 participants learned 12 conditional discriminations, MTS tests evaluated the emergence of three 5-member equivalence classes. These tests were followed by sorting tests that were conducted in clustering or stacking formats. After training, 20% of participants formed the classes. Of the 75% who did not, classes emerged for 36% and 15% of participants during stacking and clustering, respectively, with a criterion of consecutive class-indicative sorts in the first two sorting tests, and by 45% and 15% of participants during stacking and clustering, respectively, with a criterion of two successive class-indicative sorts in any of the four sorting tests. Overall, a somewhat higher percentage of participants formed classes during stacking than during clustering, sometimes on a delayed basis. Finally, even higher yields were obtained when criterion was defined as two nonconsecutive class-indicative sorting tests. When classes did not form, clustering rather than stacking tests generated larger proportions of stereotyped, participant-defined, three-member classes and two-term relations but stacking generated more one-stimulus “groupings.” Thus, class formation was influenced by sorting format and the criteria used to define class emergence. Also, sorting influenced performances even during failed class formation.

Simple discrimination reversal procedures have been successful in demonstrating functional equivalence classes in animals. The current study tested whether class expansion could be demonstrated in rats following the formation of functional equivalence classes. Olfactory stimuli were assigned to two arbitrary sets, and rats were trained on a successive simple discrimination task to respond to members of only one set at a time. When discriminated responding emerged, the reinforcement contingencies were reversed. After repeated reversals, probe sessions demonstrated functional equivalence classes in 14 of 15 rats across three experiments. Subsequently, the reversal procedure was used to train functional equivalence between one exemplar from each established class and two novel stimuli. Tests for class expansion, conducted between stimuli in the same set but without a history of training in the same session, were mixed. Experiment 1, which began expansion training after six-member classes were formed, did not provide clear evidence for class expansion. In Experiments 2 and 3, where expansion training began with smaller classes, class expansion was observed in six of eight rats. Class expansion is a property shared with human equivalence classes, suggesting that the discrimination reversal procedure provides a promising strategy for continuing research on equivalence in animals.

Two recent studies provided participants with their preferred music on synchronous schedules for increasing and decreasing their walking speed on a treadmill. Both studies demonstrated schedule control with most of their participants; however, the researchers speculated that presession rules may have contributed to this control. The purpose of this study was to examine how rules influenced schedule control of walking speed with the treadmill preparation. First, we randomly assigned 39 participants to one of three groups: accurate rules, inaccurate rules, or no rules. Second, we identified each participant's preferred music genre using a conjugate assessment. Third, we exposed each participant to five mixed-schedule components while they walked on a treadmill. The components differed in terms of the walking-speed requirements for participants to access reinforcement, and participants received accurate rules, inaccurate rules, or no rules about upcoming contingencies prior to each component presentation. Results showed schedule control emerged for (a) 8 of 13 (61%) participants in the accurate rules group, (b) 0 of 13 (0%) participants in the inaccurate rule group, and (c) 1 of 13 (7.69%) participants in the no rules group. Results also showed that 24 of 26 (92.3%) participants in the two rules groups changed their speed in accordance with the rules before contacting consequences. Collectively, the findings suggest that rules can either facilitate or impede schedule control with synchronous reinforcement schedules during the treadmill preparation.

Previous research has shown that divided-attention performance is sensitive to variations in relative reinforcement in a manner consistent with the generalized matching law. Two experiments with pigeons were designed to better understand the effects of different reinforcement conditions on divided-attention performance. Experiment 1 asked whether separate experience with different relative reinforcement probabilities for elements alone would produce changes in performance during nondifferentially reinforced divided-attention trials with compound samples consisting of those elements. The results suggest that accuracy following compound sample trials varied as a function of relative reinforcement experienced in element trials in a manner consistent with the matching law. Experiment 2 used an adjusting-sample-duration procedure to maintain constant accuracy on element and divided-attention trials and varied the probability of reinforcement across conditions. The sample durations that were required to maintain constant accuracy increased as reinforcement probability decreased even though that longer sample durations were required to maintain accuracy for compound-sample trials than for element-sample trials (the element-superiority effect). Overall, the present results are consistent with the notion that increased attention is allocated to stimuli that are associated with more reinforcement.

My collaboration with Peter Urcuioli started with research on delayed matching to sample. Initially we asked, what do pigeons remember during the delay in delayed matching to sample: a retrospective coding of the sample or a prospective coding of the comparison-related response? This led us to examine the basis of the differential outcomes effect. Why are samples associated with differential outcomes learned faster and remembered better than samples associated with common outcomes? This research helped us discover a procedure that resulted in functional stimulus equivalence: Samples associated with the same comparison are commonly associated. This research led Peter to develop his creative model of pigeon equivalence class formation. His model predicts the conditions under which pigeons satisfy the three components of what is known as Sidman equivalence: reflexivity, symmetry, and transitivity, phenomena that are difficult to demonstrate in pigeons. Importantly, his model predicts the opposite of reflexivity (anti-reflexivity) and symmetry (anti-symmetry). Research confirming Peter's model laid to rest the belief that the emergent relations defining Sidman equivalence can be satisfied only by an organism capable of using language. In his long career, Peter Urcuioli has made an important and long-lasting contribution to the field of learning and comparative cognition.

Dogs show numerousness, which is the ability to identify the larger of two stimuli, most often the number of treats on a plate. However, dogs seem to use mechanisms other than counting to make this discrimination. This study builds on existing research by controlling for (a) olfaction, (b) the surface area of the stimuli, and (c) delivery of a single reinforcer contingent on correct choices in the trained task. Nine dogs were trained to select a dish with 5 dots/treats in a sealed container when presented with comparison stimuli of 1, 4, and 9 dots/treats. The dogs showed numerousness in discriminating between dishes with 1 versus 5 dots, with consistent performance of more than 80% correct. Two dogs could discriminate 4 versus 5 dots, and three dogs learned the 9- versus 5-dot discrimination in which there is a conflict between selecting the larger option and selecting the 5 dots to gain reinforcement in the task. Knowledge of numerical competency, particularly training dogs to select the nonreinforced choice, can offer strategies to facilitate cognitive enrichment and learning in animals or offer enhancement of the capabilities of working dogs where the concept of number might be advantageous in providing additional skills.