Increasing the saliency of behavior-consequence relations for children with autism who exhibit persistent errors

Reinforced behavioral variability in the valproate rat model of autism spectrum disorder

Individuals diagnosed with autism spectrum disorder (ASD) tend to display restricted, repetitive behaviors and deficits in social interaction. Rats exposed to valproate (VPA) in utero have been shown to model symptoms of ASD. In previous research, VPA rats engaged in less social interaction and more repetitive responding than controls. The purpose of the present study was to further investigate behavioral variability in the VPA rat model of ASD by testing VPA and control rats in a reinforced-behavioral-variability operant task. In this procedure, rats emitted sequences of lever presses, some of which produced food. During baseline, food was delivered probabilistically, and variability was not required. Next, rats were exposed either to a variability contingency, in which food was only delivered following sequences that differed sufficiently from previous sequences (i.e., variability required), or to a yoked contingency, in which variability was not required. We hypothesized that VPA rats would behave less variably than controls in this task. However, VPA and control rats responded similarly variably when variability was required. Furthermore, VPA rats behaved slightly more variably than controls during baseline and yoked conditions, when variability was not required. These findings contribute to the complex literature surrounding the VPA rat model of ASD.

Promoting the emergence of tacting three-digit numerals through a chain prompt combined with matrix training

Children with autism spectrum disorder (ASD) have difficulty generalizing from directly trained responses to untrained responses (i.e., emergent responding). In this study, we used a chain prompt combined with matrix training to teach 2 participants with ASD to tact 192 three-digit numerals. We used a multiple-baseline design across matrices to evaluate the treatment effects on trained and untrained tacts of numerals. Both participants mastered all numerals exposed to training and all numerals not exposed to training after 3 to 5 sixteen-trial sessions per matrix. One participant learned to tact 8 numerals for each 1 numeral exposed to direct training, and the other participant learned to tact 12 numerals for each 1 numeral exposed to direct training. We discuss these results relative to the effectiveness and efficiency of our chain prompt combined with matrix training for teaching tacting skills for targets with shared stimulus properties that facilitate generalization to untrained targets.

Stimulus Control Research and Practice: Considerations of Stimulus Disparity and Salience for Discrimination Training

Stimulus control plays a prominent role in behavior-analytic service delivery, as many discrimination skills are necessary for daily interactions. Clarification and standardization of terminology are necessary for the advancement of research and practice on stimulus control. The purpose of the present article is to provide an overview of stimulus control and discrimination training as they relate to the disparity and salience of stimuli. An overview and examples of stimulus disparity and stimulus salience are provided, followed by recommendations for efficacious service delivery.

The influence of correlations between noncritical features and reinforcement on stimulus generalization

One strategy to program for generalization is to vary noncritical features in teaching exemplars, thereby avoiding noncritical features from being highly correlated with reinforcement and thus gaining faulty stimulus control. In the current translational evaluation, 2 groups of adults of typical development were taught to respond to arbitrary stimuli with experimenter-defined critical and noncritical features in a matching-to-sample task. The teaching arrangement used for 1 group programmed for low correlation between noncritical features and reinforcement; the teaching arrangement used for the other group programmed for high correlation between noncritical features and reinforcement. Participants in the former group displayed (a) faster acquisition of matching, (b) less variability in correct responding, and (c) a decreased likelihood of faulty stimulus control developing during training. The results contribute towards advancing the study of stimulus control and developing an explicit technology of generalization to better serve consumers of the application of our science.

A preliminary investigation of fixed and repetitive models during object imitation training

Empirically based guidelines for imitation training for children with Autism Spectrum Disorder (ASD) are limited and there is no existing evidence about what types of imitative models foster faster acquisition of imitation in children with ASD. We compared rates of acquisition for two different methods for presenting the imitative model (i.e., repetitive, fixed) in simple (Experiment 1) and conditional (Experiment 2) discrimination arrangements. The results suggest that some children with ASD may acquire imitation more rapidly when repetitive models, rather than fixed models are used to present the target skill. In Experiment 3, we investigated the features of object imitation models that might influence acquisition. The results of Experiment 3 suggest that the dynamic nature of repetitive models might be responsible for the differential acquisition we observed in the earlier two Experiments. Additionally, the presence of an outcome (e.g., stacked blocks) during training does not enhance acquisition.

Back-translating behavioral intervention for autism spectrum disorders to mice with blunted reward restores social abilities

The mu opioid receptor (MOR) plays a critical role in modulating social behavior in humans and animals. Accordingly, MOR null mice display severe alterations in their social repertoire as well as multiple other behavioral deficits, recapitulating core and secondary symptoms of autism spectrum disorder (ASD). Such behavioral profile suggests that MOR dysfunction, and beyond this, altered reward processes may contribute to ASD etiopathology. Interestingly, the only treatments that proved efficacy in relieving core symptoms of ASD, early behavioral intervention programs, rely principally on positive reinforcement to ameliorate behavior. The neurobiological underpinnings of their beneficial effects, however, remain poorly understood. Here we back-translated applied behavior analysis (ABA)-based behavioral interventions to mice lacking the MOR (Oprm1^-/-), as a model of autism with blunted reward processing. By associating a positive reinforcement, palatable food reward, to daily encounter with a wild-type congener, we were able to rescue durably social interaction and preference in Oprm1^-/- mice. Along with behavioral improvements, the expression of marker genes of neuronal activity and plasticity as well as genes of the oxytocin/vasopressin system were remarkably normalized in the reward/social circuitry. Our study provides further evidence for a critical involvement of reward processes in driving social behavior and opens new perspectives regarding therapeutic intervention in ASD.

Effects of neutral and enthusiastic praise on the rate of discrimination acquisition

Previous research has shown that praise is an effective reinforcer; however, few researchers have evaluated whether qualitative differences in praise affect responding. The purpose of the current study was to compare the effects of neutral, enthusiastic, and no praise on the rate of matching-to-sample acquisition during discrete-trial training with adults diagnosed with autism and an intellectual disability. In addition, we evaluated preference for neutral, enthusiastic, and no praise. All three participants acquired responses slightly faster during the enthusiastic praise condition. Preference assessment results showed that one participant preferred enthusiastic praise, whereas the two other participants showed indiscriminate selections.