The generalization-across-dimensions model applied to conditional temporal discrimination.

Can simple choice conditional-discrimination choice be accounted for by recent quantitative models of combined stimulus and reinforcer control? In Experiment 1, two sets of five blackout durations, one using shorter intervals and one using longer intervals, conditionally signaled which subsequent choice response might provide food. In seven conditions, the distribution of blackout durations across the sets was varied. An updated version of the generalization-across-dimensions model nicely described the way that choice changed across durations. In Experiment 2, just two blackout durations acted as the conditional stimuli and the durations were varied over 10 conditions. The parameters of the model obtained in Experiment 1 failed adequately to predict choice in Experiment 2, but the model again fitted the data nicely. The failure to predict the Experiment 2 data from the Experiment 1 parameters occurred because in Experiment 1 differential control by reinforcer locations progressively decreased with blackout durations, whereas in Experiment 2 this control remained constant. These experiments extend the ability of the model to describe data from procedures based on concurrent schedules in which reinforcer ratios reverse at fixed times to those from conditional-discrimination procedures. Further research is needed to understand why control by reinforcer location differed between the two experiments.

Facilitating the emergence of intraverbal tacts by autistic children via joint control.

Rodriguez et al. (2022) discovered that teaching four component skills was sufficient to facilitate the emergence of intraverbal tacts across four applications with three participants. Our study replicated and evaluated an extension of this procedure that was directed at facilitating intraverbal tacts when a child learns the component skills but continues to fail to produce intraverbal tacts. The extension consisted of procedures to enhance the divergent control exerted by the auditory stimulus (i.e., the question) and the discriminability of joint control. Intraverbal tacts emerged for all three participants after undergoing the extension procedures. These results are discussed in the context of a conceptual analysis of intraverbal tacts and the potential role of joint control.

Lack of reinforcement is hard to "bear": Assessing judgment bias in grizzly bears (Ursus arctos horribilis).

Cognitive biases reveal underlying affective state by indicating optimism and pessimism. This methodology may permit assessment of positive welfare in animals that have few validated positive welfare indicators, such as bears. Our goal was to validate a judgment bias test for assessing optimism in brown bears, using a touchscreen. After training the bears on a conditional discrimination, we compared responses to an ambiguous stimulus in a 2 × 2 nested design involving four experimental conditions representing presence or absence of a behind-the-scenes tour and presence or absence of a keeper training session with food reinforcement. We recorded bears' behavior during the conditions as a measure of convergent validity. Testing revealed the possibility of pessimism in the absence of reinforcement in one bear. More frustration behaviors were also observed during the no food reinforcement conditions. This is the first experimental demonstration of brown bears using a touchscreen and one of only three reports in which bears have been reported to perform a conditional discrimination. This method of assessing underlying affective state shows promise for the future.

Divided stimulus control depends on differential and nondifferential reinforcement: Testing a quantitative model.

We investigated the effects of differential and nondifferential reinforcers on divided control by compound-stimulus dimensions. Six pigeons responded in a delayed matching-to-sample procedure in which a blue or yellow sample stimulus flashed on/off at a fast or slow rate, and subjects reported its color or alternation frequency. The dimension to report was unsignaled (Phase 1) or signaled (Phase 2). Correct responses were reinforced with a probability of .70, and the probability of reinforcers for errors varied across conditions. Comparison choice depended on reinforcer ratios for correct and incorrect responding; as the frequency of error reinforcers according to a dimension increased, control (measured by log d) by that dimension decreased and control by the other dimension increased. Davison and Nevin's (1999) model described data when the dimension to report was unsignaled, whereas model fits were poorer when it was signaled, perhaps due to carryover between conditions. We are the first to test this quantitative model of divided control with reinforcers for errors and when the dimension to report is signaled; hence, further research is needed to establish the model's generality. We question whether divided stimulus control is dimensional and suggest it may instead reflect joint control by compound stimuli and reinforcer ratios.

Comparing a modified simple-conditional with the conditional-only methods in teaching Chinese children with autism.

Instruction in auditory-visual conditional discriminations for young children with autism spectrum disorder is typically based on either a conditional-only or a simple-conditional method. In this study, we evaluated a modified simple-conditional method in which we removed the steps for which visual comparisons were presented in isolation. We compared this modified simple-conditional method with the conditional-only method when teaching auditory-visual conditional discriminations to six young Chinese children with autism spectrum disorder. We included two efficiency measures: total sessions and time to mastery. Our results replicated the findings of previous research in that both methods were efficacious for all but one participant. Although efficacy outcomes were similar across methods, the conditional-only method was more efficient across participants according to sessions and time to mastery. Thus, the results add to support for the use of the conditional-only method to teach auditory-visual conditional discriminations.

Developing a Preference Scale for a Bear: From "Bearly Like" to "Like Beary Much".

A preference scale for use by nonhuman animals would allow them to communicate their degree of liking for individual items rather than just relative preferences between pairs of items. It would also allow animals to report liking for images of objects that would be difficult to directly interact with (e.g., potential mates and habitat modifications). Such scales can easily be presented using touchscreen technology. Few zoos have used touchscreen technology for species other than nonhuman primates. I present a description of efforts taken to create such a scale for use with a single zoo-housed American black bear (Ursus americanus). Although the bear did not reach a high level of proficiency with assigning preferred and non-preferred food items to categorical responses of "like" and "dislike," she was able to learn how to use the like and dislike buttons differentially for a single preferred and less preferred food item and she selected the correct response button for the preferred item at above chance levels. These data contribute to our limited understanding of black bear cognition and suggest that conditional discriminations may be difficult for black bears. This finding can inform continued efforts to create a simpler tool for nonhumans to communicate their preferences to human caregivers in a more nuanced way than is currently possible. More generally, the current study contributes to the growing body of work supporting the use of touchscreen technology for providing enrichment to less studied species like bears.

A parametric analysis of procedural fidelity errors following mastery of a task: A translational study.

Procedural fidelity is defined as the extent to which the independent variable is implemented as prescribed. Research using computerized tasks has shown that fidelity errors involving consequences for behavior can hinder skill acquisition. However, studies examining the effects of these errors once skills have been mastered are lacking. Thus, this translational study investigated the effects of varying levels of fidelity following mastery of a computerized arbitrary matching-to-sample task. A group design (consisting of five groups) was used in which college students initially completed 250 trials during which no programmed errors (i.e., perfect fidelity) were arranged, followed by an additional 250 trials with consequences delivered across various levels of fidelity (i.e., 20, 40, 60, 80, and 100% of trials administered without errors). The results showed that participants assigned to higher fidelity conditions performed better (on average). These results extended the findings of previous studies by demonstrating how errors involving consequences affect behavior across various stages of learning.

Prior experience modifies acquisition trajectories via response-strategy sampling.

Few studies have considered how signal detection parameters evolve during acquisition periods. We addressed this gap by training mice with differential prior experience in a conditional discrimination, auditory signal detection task. Naïve mice, mice given separate experience with each of the later correct choice options (Correct Choice Response Transfer, CCRT), and mice experienced in conditional discriminations (Conditional Discrimination Transfer, CDT) were trained to detect the presence or absence of a tone in white noise. We analyzed data assuming a two-period model of acquisition: a pre-solution and solution period (Heinemann EG (1983) in The Presolution period and the detection of statistical associations. In: Quantitative analyses of behavior: discrimination processes, vol. 4, pp. 21-36). Ballinger. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.536.1978andrep=rep1andtype=pdf ). The pre-solution period was characterized by a selective sampling of biased response strategies until adoption of a conditional responding strategy in the solution period. Correspondingly, discriminability remained low until the solution period; criterion took excursions reflecting response-strategy sampling. Prior experience affected the length and composition of the pre-solution period. Whereas CCRT and CDT mice had shorter pre-solution periods than naïve mice, CDT and Naïve mice developed substantial criterion biases and acquired asymptotic discriminability faster than CCRT mice. To explain these data, we propose a learning model in which mice selectively sample and test different response-strategies and corresponding task structures until they exit the pre-solution period. Upon exit, mice adopt the conditional responding strategy and task structure, with action values updated via inference and generalization from the other task structures. Simulations of representative mouse data illustrate the viability of this model.

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)

Reducing the occurrence of mouthing and jumping in a dog through conditional discrimination training.

Many approaches for reducing unwanted behavior use punishment, extinction, or noncontingent reinforcement. Other methods focus on teaching and reinforcing alternative behaviors that can replace the unwanted behavior. Another strategy can be to change the stimulus control of the unwanted behavior. The present study investigated if conditional discrimination training using positive reinforcement could reduce undesirable behaviors in a pet dog. After conditional discrimination training, two unwanted behaviors (jumping and mouthing) occurred reliably in the presence of new discriminative stimuli, while other behaviors occurred in the presence of the discriminative stimuli that had previously produced these unwanted behaviors. This experiment demonstrates that conditional discrimination training can be an effective way to control the frequency of an unwanted behavior by controlling the frequency of the presentation of a discriminative stimulus.

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.

Replication of a skills assessment for auditory-visual conditional discrimination training.

Auditory-visual conditional discrimination training (e.g., receptive identification training, listener responses; AVCD) is ubiquitous in early intervention and special education programs. Nevertheless, some learners with Autism Spectrum Disorder (ASD) do not appear to benefit from this training despite use of empirically validated treatments. To prevent exposure to extended training that does not lead to learning, a skills assessment that measures skills related to AVCD training will be useful for educators and practitioners. The current study replicated the skills assessment developed and evaluated by Kodak et al. (2015) with 8 participants with ASD who received behavior analytic intervention that included at least 1 goal related to AVCD training. Two of the 8 participants mastered all skills included in the assessment except scanning. In addition, 5 participants' responding failed to reach mastery during subsequent exposure to AVCD training, which further demonstrated the predictive utility of the skills assessment.

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.

Facilitating the emergence of intraverbal tacts in children with autism spectrum disorder: A preliminary analysis.

Intraverbal tacts are an example of multiply controlled verbal behavior. More specifically, they are verbal responses under control of both a nonverbal (visual) stimulus (e.g., a green ball) and a verbal (auditory) stimulus (e.g., "What color?" vs. "What shape?"). Studies have shown that verbal behavior training can be arranged in a way that would lead to the emergence of other verbal operants, including multiply controlled (convergent) intraverbals. Our study sought to evaluate the relevance of a specific set of component skills on the emergence of intraverbal tacts in children with an autism spectrum disorder. Intraverbal tacts were observed only when all component skills were mastered, suggesting that this set of skills was sufficient to produce emergent verbal performance. Preliminary data were obtained on the necessity of 4 of the 6 component skills and tentatively suggest that they may be necessary to produce emergent intraverbal tacts, at least under some conditions.

What's not to like about Likert? Developing a nonverbal animal preference scale (NAPS).

Rating scales, such as Likert scales, are incredibly flexible and intuitive tools for measuring individuals' rating of agreement with or relative preference for many types of stimuli. For humans, this typically involves ratings of agreement between end points representing distinct attitudes or beliefs; For example, strongly disagree to strongly agree. Nonverbal versions of Likert scales have also been presented to children, allowing them to indicate their degree of preference, pain, or happiness. However, before the current study, no known efforts had been made to develop a nonverbal rating scale for use with nonhuman animals. Such a scale would be a useful welfare tool, allowing nonverbal individuals to indicate not just relative preferences between pairs of items but their degree of liking for individual items. I present an outline of the steps taken to create such a scale for use with three zoo-housed gorillas. Two gorillas succeeded in associating preferred and less preferred foods with different response buttons but none of the gorillas were able to effectively use the neutral response button. It is possible that limits in gorillas' capacity for conditional discriminations and/or conceptualization of constructs as abstract as "liking" impeded training. These data are relevant for understanding gorilla cognition and can inform continued efforts to create a tool for nonhumans to communicate their preferences to human caregivers in a more nuanced way than is currently possible.

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.

Conditional Learning Deficits in Children with ADHD can be Reduced Through Reward Optimization and Response-Specific Reinforcement.

When children with ADHD are presented with behavioral choices, they struggle more than Typically Developing [TD] children to take into account contextual information necessary for making adaptive choices. The challenge presented by this type of behavioral decision making can be operationalized as a Conditional Discrimination Learning [CDL] task. We previously showed that CDL is impaired in children with ADHD. The present study explores whether this impairment can be remediated by increasing reward for correct responding or by reinforcing correct conditional choice behavior with situationally specific outcomes (Differential Outcomes). An arbitrary Delayed Matching-To-Sample [aDMTS] procedure was used, in which children had to learn to select the correct response given the sample stimulus presented (CDL). We compared children with ADHD (N = 45) and TD children (N = 49) on a baseline aDMTS task and sequentially adapted the aDMTS task so that correct choice behavior was rewarded with a more potent reinforcer (reward manipulation) or with sample-specific (and hence response-specific) reinforcers (Differential Outcomes manipulation). At baseline, children with ADHD performed significantly worse than TD children. Both manipulations (reward optimization and Differential Outcomes) improved performance in the ADHD group, resulting in a similar level of performance to the TD group. Increasing the reward value or the response-specificity of reinforcement enhances Conditional Discrimination Learning in children with ADHD. These behavioral techniques may be effective in promoting the learning of adaptive behavioral choices in children with ADHD.

Central Thalamic-Medial Prefrontal Control of Adaptive Responding in the Rat: Many Players in the Chamber.

The medial prefrontal cortex (mPFC) has robust afferent and efferent connections with multiple nuclei clustered in the central thalamus. These nuclei are elements in large-scale networks linking mPFC with the hippocampus, basal ganglia, amygdala, other cortical areas, and visceral and arousal systems in the brainstem that give rise to adaptive goal-directed behavior. Lesions of the mediodorsal nucleus (MD), the main source of thalamic input to middle layers of PFC, have limited effects on delayed conditional discriminations, like DMTP and DNMTP, that depend on mPFC. Recent evidence suggests that MD sustains and amplifies neuronal responses in mPFC that represent salient task-related information and is important for detecting and encoding contingencies between actions and their consequences. Lesions of rostral intralaminar (rIL) and ventromedial (VM) nuclei produce delay-independent impairments of egocentric DMTP and DNMTP that resemble effects of mPFC lesions on response speed and accuracy: results consistent with projections of rIL to striatum and VM to motor cortices. The ventral midline and anterior thalamic nuclei affect allocentric spatial cognition and memory consistent with their connections to mPFC and hippocampus. The dorsal midline nuclei spare DMTP and DNMTP. They have been implicated in behavioral-state control and response to salient stimuli in associative learning. mPFC functions are served during DNMTP by discrete populations of neurons with responses related to motor preparation, movements, lever press responses, reinforcement anticipation, reinforcement delivery, and memory delay. Population analyses show that different responses are timed so that they effectively tile the temporal interval from when DNMTP trials are initiated until the end. Event-related responses of MD neurons during DNMTP are predominantly related to movement and reinforcement, information important for DNMTP choice. These responses closely mirror the activity of mPFC neurons with similar responses. Pharmacological inactivation of MD and adjacent rIL affects the expression of diverse action- and outcome-related responses of mPFC neurons. Lesions of MD before training are associated with a shift away from movement-related responses in mPFC important for DNMTP choice. These results suggest that MD has short-term effects on the expression of event-related activity in mPFC and long-term effects that tune mPFC neurons to respond to task-specific information.

Comparison of sounds and words as sample stimuli for discrimination training.

A portion of children diagnosed with autism spectrum disorder (ASD) have difficulty acquiring conditional discrimination. However, previous researchers suggested that the discrimination of nonverbal auditory stimuli may be acquired more efficiently (Eikeseth & Hayward, 2009; Uwer, et al., 2002). For example, a child may learn to touch a picture of a piano after hearing the musical instrument more quickly than when the auditory stimulus is the spoken word "piano." The purpose of the present study was to extend previous research by assessing the acquisition of conditional discriminations with sample stimuli presented as either automated spoken words or high- and low-disparity nonverbal auditory stimuli (i.e., environmental sounds). Conditional discriminations with high-disparity environmental sounds as sample stimuli were acquired rather than or more efficiently than those trained with low-disparity environmental sounds and words as sample stimuli.