Matching-to-Sample Task Training of a Killer Whale (Orcinus orca).

Matching-to-sample tasks have been a useful method in visual cognitive studies on non-human animals. The use of touch panels in matching-to-sample tasks has contributed to cognitive studies on terrestrial animals; however, there has been a difficulty in using these devices underwater, which is one of the factors that has slowed the progress of visual studies on underwater animals. Cetaceans (e.g., dolphins and whales) are highly adapted to underwater environments, and further studies on their cognitive abilities are needed to advance our understanding of the interactions between environmental factors and the evolution of cognitive abilities. In this study, we aimed to develop a new experimental method in which a captive killer whale performed a matching-to-sample task using a monitor shown through an underwater window as if a touch panel were used. In order to confirm the usefulness of this method, one simple experiment on mirror image discrimination was conducted, and the pairs with mirror images were shown to be more difficult to identify than the pairs with other normal images. The advantages of using this method include (1) simplicity in the devices and stimuli used in the experiments, (2) appropriate and rigorous experimental control, (3) the possibility of increasing the number of individuals to be tested and interspecies comparisons, and (4) contributions to animal welfare. The use of this method solves some of the problems in previous visual cognitive studies on cetaceans, and it suggests the further possibility of future comparative cognitive studies. It is also expected to contribute to animal welfare in terms of cognitive enrichment, and it could help with the proposal of new exhibition methods in zoos and aquariums.

Sample-comparison mapping and joint stimulus control.

A matching-to-sample task with a 3-sample, 2-comparison mapping has been found to engender joint control by the stimuli that signaled the samples (keylight) and the inter-trial interval (houselight), with a trade-off in the degree of control exerted by each stimulus. To learn about the boundary conditions for the establishment of that joint stimulus control, we trained pigeons in a similar task, but featuring a one-to-one sample-comparison mapping, with two samples and two comparisons. To assess their relative influences, we ran two tests where each of the stimuli was removed: in one test, no sample keylight was presented, and in the other, the ITI was spent in darkness. Results were consistent with both stimuli influencing choice but there was no clear evidence of a trade-off between them. These results suggest that sample-comparison mapping and/or total number of samples may influence how an animal directs its attention to the stimuli available.

Revisiting Topography-Based and Selection-Based Verbal Behavior.

In topography-based verbal behavior, different antecedent stimuli control different topographies of responding, whereas in selection-based verbal behavior, different antecedent stimuli control the selection of visually distinct stimuli from an array of options. In this article, we point out three variable characteristics of selection-based behavior, highlighted by recent technological developments, that affect its similarity to topography-based behavior: The extent to which stimuli can be constructed from minimal units, the size and composition of the selection array, and the similarity of response-produced stimuli to verbal stimuli that are prevalent in the speaker's verbal community. Although a distinction between topography-based and selection-based behavior has merit, particular characteristics of a selection-based verbal behavior modality may often be more relevant for researchers and clinicians to consider than its status as selection-based.

Altered prefrontal beta oscillatory activity during removal of information from working memory in obsessive-compulsive disorder.

BACKGROUND: Obsessive-compulsive disorder (OCD) is related to working memory impairment. Since patients with OCD have difficulty controlling their obsessive thoughts, removal of irrelevant information might be important in the pathophysiology of OCD. However, little is known about brain activity during the removal of information from working memory in patients with OCD. Our goal was to explore potential deficits in inhibitory function related to working memory processes in patients with OCD. METHODS: Sixteen OCD patients and 20 healthy controls (HCs) were recruited. We compared in prefrontal alpha and beta band activity derived from magnetoencephalography (MEG) between patients with OCD and HCs during multiple phases of information processing associated with working memory, especially in post-trial period of the visuospatial working memory task (the delayed matching-to-sample task), which is presumed to be related to the information removal process of working memory. RESULTS: Prefrontal post-trial beta power change (presumed to occur at high levels during the post-trial period) exhibited significant reductions in patients with OCD compared to HCs. In addition, the post-trial beta power change was negatively correlated with Obsessive-Compulsive Inventory-Revised total scores in patients with OCD. CONCLUSIONS: These findings suggest that impairment in the removal of information from working memory might be a key mechanism underlying the inability of OCD patients to rid themselves of their obsessions.

Evidence of precurrent responses expanding equivalence classes in a delayed matching-to-sample task.

Delayed matching to sample (DMTS) increases the probability of equivalence class formation. Precurrent responses can mediate the retention interval in DMTS trials and control the selection of comparisons. In human participants, precurrent responses usually consist of naming the experimental stimuli based on their similarities to meaningful stimuli with preexperimental history. We tested whether precurrents expand classes by serving as nodes between experimental and meaningful stimuli. A DMTS (2 s) was used throughout the entire experiment. Eleven undergraduates learned A1B1 and A2B2 relations and then were submitted to ArC trials that required them to answer math problems presented during the DMTS interval: when the sample was A1, the problems resulted in 12 and C1 was correct; when the sample was A2, they resulted in 9 and C2 was correct. Response-as-node tests assessed whether participants would relate B1 and C1 to the printed number 12 and B2 and C2 to the printed number 9. Ten participants responded accordingly to this pattern, showing that the responses to the problems expanded the classes. Parity tests using the words "even" and "odd" further confirmed this hypothesis. These results contribute to understanding why DMTS enhances equivalence performances. Implications of using this procedure in stimulus-equivalence studies are discussed.

A 108-h total sleep deprivation did not impair fur seal performance in delayed matching to sample task.

While the majority of studies have concluded that sleep deprivation causes detrimental effects on various cognitive processes, some studies reported conflicting results. We examined the effects of a 108-h total sleep deprivation (TSD) on working memory in the northern fur seal, an animal with unusual sleep phenomenology and long-range annual migrations. The performance of fur seals was evaluated in a two-choice visual delayed matching to sample (DMTS) task, which is commonly used to evaluate working memory. In baseline conditions, the performance of fur seals in a DMTS task based on the percentage of errors was somewhat comparable with that in nonhuman primates at similar delays. We have determined that a 108-h TSD did not affect fur seals' performance in a visual DMTS task as measured by overall percentage of errors and response latencies. On the contrary, all fur seals improved task performance over the study, including the baseline, TSD and recovery conditions. In addition, TSD did not change the direction and strength of the pattern of behavioral lateralization in fur seals. We conclude that a 108-h TSD did not interfere with working memory in a DMTS test in northern fur seals.

Procedural parameters in equivalence-based instruction with individuals diagnosed with autism: A call for systematic research.

Equivalence-based instruction (EBI) is an efficient and efficacious methodology to establish equivalence classes that has been used to teach various academic skills to neurotypical adults. Although previous reviews confirmed the utility of EBI with participants with developmental disabilities, it is unclear whether certain procedural parameters are associated with positive equivalence outcomes. We extended previous reviews by categorizing studies that used EBI with individuals diagnosed with autism spectrum disorder and assessed whether any procedural parameters were associated with better equivalence responding. Due to the wide variability of procedural parameters in EBI research, the best procedural permutations to form equivalence classes with individuals diagnosed with autism spectrum disorder are still unknown. Thus, this paper serves as a call to action for applied researchers. Specifically, we encourage and invite researchers to systematically investigate the necessary variables or combination of variables that may lead to successful equivalence class formation.

Is superstitious responding a matter of detectability? A replication of Killeen (1978).

Organisms may sometimes behave as if a contingency exists between behavior and consequences, even if this is not actually the case. Killeen (1978) suggested that such superstition occurs because of factors that bias subjects to behave "superstitiously" rather than because of failures of discrimination. We systematically replicated Killeen's experiment and compared contingency discrimination between different consequences. Six pigeons responded in a matching-to-sample procedure in which a response-independent or response-dependent stimulus change, food delivery, or blackout occurred. The pigeons reported whether the consequence was response dependent or response independent by choosing between two side keys. Discrimination was strongest after stimulus changes, weaker after blackouts, and weakest after food deliveries. These differences persisted even after additional training, suggesting asymmetries that may reflect differences in the disruptive effects of different consequences on remembering and/or behavioral mnemonics. Importantly, the pigeons were not biased to report response-dependent consequences unless that response was consistent with locational biases; that is, they behaved "superstitiously" when there was a reason to be biased to do so. These findings corroborate Killeen's and demonstrate that behavior may deviate from contingencies not necessarily because subjects cannot discriminate those contingencies but because they are biased to behave otherwise.

The Problem of Class Breakdown in Sidman's (1994, 2000) Theory about the Origin of Stimulus Equivalence.

Sidman (1994, 2000) hypothesized that equivalence relations are a direct outcome of reinforcement contingencies. This theory is problematic because contingencies do not always result in equivalence. Sidman proposed that equivalence relations may conflict with analytic units, the other outcome of contingencies (e.g., in conditional discriminations with common responses/reinforcers). This conflict may result in a generalized class breakdown and a failure to pass equivalence tests. This is more likely in nonhumans, very young humans, etc. The conflict can also result in a selective class breakdown and success in equivalence tests. This occurs after experience shows the organism the necessity and utility of this process. The nature of that experience and the class breakdown processes were not described by Sidman. I explored the implications of the following hypotheses for Sidman's theory. First, conditional discriminations with a common response/reinforcer result in a generalized class breakdown when participants fail to discriminate emergent relations incompatible with contingencies from those compatible. Second, learning to discriminate between the two requires a history of multiple exemplar training (MET). This implies that equivalence class breakdown is a common response to exemplars that have nothing in common except their relations. This, however, contradicts Sidman's views about the impossibility of such process in the absence of a complex verbal repertoire. If that type of learning from MET is possible, then the possibility that MET results in the selective formation of equivalence classes must be admitted, and the utility of hypothesizing that equivalence is a direct outcome of reinforcement contingencies can be questioned.

Use of conditional-discrimination training in remembering relatives in a man with Alzheimer’s Disease

In this study, a 72-year-old man with Alzheimer’s disease and a Mini-Mental Status (MMS) score of 25 participated. The participant was presented for class-formation sorting tests and conditionaldiscrimination training sequences and tests with portraits of close family members, their names, and family relationships as stimuli. The purpose of the study was to identify intact relations between stimuli, stimulus control issues and thereafter reestablish relations between stimuli. In the sorting tests, intact and weakened stimulus relations were identified. In addition, the results showed how correct stimulus control was reestablished after tailoring the conditional-discrimination training after the participant had shown systematical incorrect responding to some of the presented stimuli. Key words: conditional discrimination, matching-to-sample, dementia, sorting test, stimulus control (AU)

Effects of proactive interference on olfactory memory in dogs.

Proactive interference (PI) occurs when memories of past events or stimuli intrude in the present moment, causing working memory (WM) errors. These errors are often measured through WM tests such as matching-to-sample (MTS). When the repetition of individual stimuli increases, there is a greater chance of these intrusions, and thus there can be a decrease in accuracy in such tasks. In two experiments, we explored the nature of PI on dog working memory. First, we manipulated the size of the set of odors (2, 6, trial-unique) used to construct each session to maximize (2-odor set) and minimize (trial-unique) within-session proactive interference during an olfactory MTS task. Matching-to-sample accuracy decreased with greater PI. Second, we adapted procedures originally designed for pigeons and rhesus macaques to determine the locus of PI in dogs. To test for proactive interference, probe trials were inserted into MTS sessions where sample odors from earlier trials reappeared as incorrect comparisons. Incorrect responses on these probe trials indicated proactive interference. These probe tests were conducted with a 0-s or 20-s retention interval in separate sessions. We found that dogs performed worse on the matching task when the source of interference (odor stimulus) was from the immediately preceding trial compared with when they were from trials further back in the session but only for the 0-s retention interval. These results are compared with previous work examining the effects of proactive interference on working memory in other species.

Ensino de leitura e escrita para alunos com deficiência intelectual baseado no Paradigma de Equivalência de Estímulos / Teaching reading and writing to students with intellectual disabilities based on stimulus equivalence instruction / Enseñar a leer y escribir a estudiantes con discapacidad intelectual basado en el Paradigma de Equivalencia de Estímulos

A formação de classes de estímulos equivalentes tem sido considerada um modelo para o estabelecimento de relações simbólicas, ou do significado, contribuindo para o ensino de leitura e escrita. O presente estudo teve como objetivo avaliar os efeitos de um módulo de ensino de um programa informatizado de leitura e escrita em crianças com deficiência intelectual matriculadas em uma escola regular. Participaram três alunos com idades entre 8 e 10 anos. O programa de ensino era aplicado na própria escola, duas a três vezes por semana, individualmente, com sessões de aproximadamente 35 minutos. Foi empregado uma avaliação geral de leitura e escrita antes e após o programa. Os resultados mostraram que quanto melhor o repertório de entrada, mais rapidamente os participantes avançaram no módulo e melhoraram seus repertórios de leitura e escrita. A realização dessa intervenção nas séries iniciais pode contribuir na aprendizagem de repertórios básicos de leitura e escrita.

The formation of stimulus equivalence classes has been considered a productive model of symbolic relations ­ or meaning ­ for teaching reading and writing. This study aimed to evaluate the effects of one module of a computerized reading and writing program for children with intellectual disabilities enrolled in a regular school. Three students aged between 8 and 10 participated in the study. The program was applied individually to each participant in the school premises across two to three weekly sessions of approximately 35 minutes each. General assessment was applied as a pre and post-test. The results showed that the better the participants' existing repertoires, the faster they advanced in the procedure and improved their reading and writing skills. Conducting this intervention in early school years can contribute to the process of leaning basic reading and writing

La formación de clases de estímulo equivalentes se ha considerado un modelo para el establecimiento de relaciones simbólicas, contribuyendo a la enseñanza de la lectura y escritura. El estudio tuvo como objetivo evaluar los efectos de un módulo didáctico de un programa computarizado de lectura y escritura en niños con discapacidad intelectual matriculados en una escuela regular. Participaron tres estu diantes de entre 8 y 10 años. El programa de enseñanza se aplicó en la escuela, de dos a tres veces por semana, de manera individual, con sesiones de aproximadamente 35 minutos. Se utilizó una evaluación general de lectura y escritura antes y después del programa. Los resultados mostraron que cuanto mejor era el repertorio de entrada, más rápido avanzaban los participantes en el módulo y mejoraban su repertorio. La realización de esta intervención en los grados iniciales puede contribuir al aprendizaje de los repertorios básicos de lectura y escritura.

Peripheral vision in matching-to-sample procedures.

Eye-tracking has been used to investigate observing responses in matching-to-sample procedures. However, in visual search, peripheral vision plays an important role. Therefore, three experiments were conducted to investigate the extent to which adult participants can discriminate stimuli that vary in size and position in the periphery. Experiment 1 used arbitrary matching with abstract stimuli, Experiment 2 used identity matching with abstract stimuli, and Experiment 3 used identity matching with simple (familiar) shapes. In all three experiments, participants were taught eight conditional discriminations establishing four 3-member classes of stimuli. Four different stimulus sizes and three different stimulus positions were manipulated in the 12 peripheral test phases. In these test trials, participants had to fixate their gaze on the sample stimulus in the middle of the screen while selecting a comparison stimulus. Eye movements were measured with a head-mounted eye-tracker during both training and testing. Experiment 1 shows that participants can discriminate small abstract stimuli that are arbitrarily related in the periphery. Experiment 2 shows that matching identical stimuli does not affect discrimination in the periphery compared to arbitrarily related stimuli. However, Experiment 3 shows that discrimination increases when stimuli are well-known simple shapes.

Domestic hens succeed at serial reversal learning and perceptual concept generalisation using a new automated touchscreen device.

Improving the welfare of farm animals depends on our knowledge on how they perceive and interpret their environment; the latter depends on their cognitive abilities. Hence, limited knowledge of the range of cognitive abilities of farm animals is a major concern. An effective approach to explore the cognitive range of a species is to apply automated testing devices, which are still underdeveloped in farm animals. In screen-like studies, the uses of automated devices are few in domestic hens. We developed an original fully automated touchscreen device using digital computer-drawn colour pictures and independent sensible cells adapted for cognitive testing in domestic hens, enabling a wide range of test types from low to high complexity. This study aimed to test the efficiency of our device using two cognitive tests. We focused on tasks related to adaptive capacities to environmental variability, such as flexibility and generalisation capacities as this is a good start to approach more complex cognitive capacities. We implemented a serial reversal learning task, categorised as a simple cognitive test, and a delayed matching-to-sample (dMTS) task on an identity concept, followed by a generalisation test, categorised as more complex. In the serial reversal learning task, the hens performed equally for the two changing reward contingencies in only three reversal stages. In the dMTS task, the hens increased their performance rapidly throughout the training sessions. Moreover, to the best of our knowledge, we present the first positive result of identity concept generalisation in a dMTS task in domestic hens. Our results provide additional information on the behavioural flexibility and concept understanding of domestic hens. They also support the idea that fully automated devices would improve knowledge of farm animals' cognition.

Effects of brief post-sample cues signaling presence or absence of reinforcers in delayed matching-to-sample.

When short-term memory is assessed in the delayed matching-to-sample (DMTS) procedure, performance is better when cues signal larger reinforcer magnitudes or higher reinforcer probabilities for correct responding. Previous studies demonstrating signaled-magnitude or signaled-probability effects presented cues for a prolonged period during the sample stimulus and/or retention interval. The present study asked whether a signaled-probability effect would occur with brief post-sample cues that signaled the presence or absence of reinforcement. Five pigeons responded in a DMTS task in which sample stimuli were sometimes followed by a 0.5-s cue signaling that reinforcers would either be available or not available in the current trial, and the retention interval varied from 0.5 s to 20 s. A reliable signaled-probability effect was found when reinforcers were arranged independently and for all correct responses, whereas a smaller, less systematic effect was found when reinforcers were arranged dependently and probabilistically. These findings highlight the importance of reinforcement contingencies and contingency discriminability in remembering, and add to the evidence showing that cues signaling differential reinforcement in DMTS may affect processes during the retention interval and comparison phase, rather than attention to the sample stimulus.

The Use of the Go/No-Go Successive Matching-to-Sample Procedure with Nonverbal Auditory Stimuli to Establish Equivalence Classes and Speaker Behavior.

The purpose of the current study was to extend the findings on the use of the go/no-go successive matching-to-sample (S-MTS) procedure to establish auditory equivalence classes. Eight college students learned to conditionally relate nonverbal auditory stimuli into three, 3-member classes. Following training, all participants met the emergence criterion for symmetry, and six out of eight participants met the emergence criterion for transitivity/equivalence. Furthermore, all participants responded with either an experimenter-defined or a unique tact, and five participants related these names intraverbally. Although these results replicate previous findings, albeit with stimuli that cannot be echoed, possible verbal mediation via tact and intraverbal behavior seems to have occurred.

Revisiting the use of two choices in the matching-to-sample procedure.

The use of two choices in the matching-to-sample (MTS) procedure has been discouraged in the literature because it may lead to "reject control," resulting in failures to establish equivalence classes. In the present study, reject control was prevented during training with the two-choice MTS procedure by presenting the correct comparison with one of five possible incorrect comparisons across trials. This procedure was compared to a six-choice MTS procedure, in which these same six comparison stimuli were presented simultaneously across trials. In Experiment 1, conditional discrimination training and emergent relations testing maintained the same number of comparison choices, two or six. Experiment 2 assessed whether training with two or six choices would result in successful tests under a different configuration from the one with which training occurred (i.e., six or two choices, respectively). In Experiment 3, the conditions were the same as in Experiment 2, but minimal instructions were given to the participants. The results showed the establishment of equivalence classes in all test conditions, thus demonstrating success of the different training conditions. The two-choice MTS procedure appears to be at least as effective as the six-choice procedure for training conditional relations and establishing equivalence classes.

Number-of-responses matching in pigeons (Columba livia): Choice biases following delay and no-sample tests.

In a symbolic matching-to-sample task, pigeons learned to discriminate between 5 and 15 key pecks (samples): different choices were correct following the smaller and the larger response requirements. Subsequently, accuracy was tested in delayed matching, with the delay spent in darkness, contrarily to previous studies, that used illuminated delays. On average, delayed choices reflected indifference between the choices, but individual analyses showed different biases, replicating previous findings. It has been suggested that the end result of a delay may be similar to presenting no sample to begin with, so we compared preferences following a delay and following trials where no pecks were required. Performance in the two situations differed and, on zero-peck trials, a bias towards the "small" choice was found. Finally, to assess if the "small" bias was due to stimulus generalization, we compared zero-peck trials and trials with small response requirements (ranging from one to four) and found a discontinuity between zero and non-zero samples that may seem to be at odds with a generalization account.

Incrementing non-matching- but not matching-to-sample is rapidly learned in an automated version of the odor span task.

The odor span task (OST) is frequently used to assess memory capacity in rodents. Odor stimuli are presented in a large arena and choices of session-novel odors produce food reward. The procedure can be described as an incrementing non-matching-to-sample contingency because on each trial one new stimulus is presented along with one or more previously presented (non-reinforced) comparison odors. An automated version of this task has recently been developed in which odors are presented with an olfactometer in an operant chamber using a successive conditional discrimination procedure. The present study compared the acquisition of matching- vs. non-matching-to-sample versions of the task with six rats tested under each procedure. All six rats trained on the non-matching variation showed rapid acquisition of the discrimination with high rates of responding to odor stimuli when they were session-novel and low rates of responding to subsequent presentations of those odors. However, only three of the six rats trained on the matching variation met acquisition criteria, and two of the three that did acquire the task required extensive training to do so. These results support findings from the OST that rats can differentiate between stimuli that are session-novel and those previously encountered, but also that a matching contingency is more difficult to learn than a non-matching arrangement. These findings parallel differences observed between acquisition of simple matching- and non-matching-to-sample tasks, but accounts such as novelty preference or the oddity preference effect may not be sufficient to explain the present results.

Training sequence effects on emergent conditional discriminations: Replication and extension to selection-based training.

We examined the replicability and generality of a previously reported training sequence effect on emergent conditional discriminations in the intraverbal naming task. In Experiment 1, a tact-intraverbal (TI) group learned first to vocally label 6 visual patterns and then to intraverbally relate pairs of verbal labels, whereas an intraverbal-tact (IT) group received the same training in the opposite sequence. Emergent conditional discriminations among pattern stimuli were assessed in match-to-sample (MTS) format. Experiment 2 was identical, except vocal tact and intraverbal training were replaced with selection-based training in which the verbal labels were text stimuli. Compared to the IT sequence, the TI sequence resulted in greater mean accuracy at test (Experiment 1), higher yields (Experiment 2), and shorter reaction times (Experiment 2). Experiment 2 data suggested the TI group's performance might be less dependent on intact intraverbal relations relative to the IT group, but related to participants' reports of visualization during intraverbal training. The results suggest the sequence effect is replicable and occurs in experimental preparations commonly used to study derived stimulus relations. They also provide novel support for the hypothesis that participant behavior during training alters sources of stimulus control available at test.