Effects of Procedural Variations in the Training of Negative Relations for the Emergence of Equivalence Relations

Teaching receptive vocabulary to two autistic children: A replicated, clinic-based, single case experimental design

Background and aims

This study was conducted in a clinical setting with the aim of replicating previously used procedures for teaching receptive vocabulary. Researchers increased the number of vocabulary words and maintained use of match-to-sample (MtS), prompting, and reinforcement procedures. Researchers were also interested in the efficacy of the intervention from caregivers' perspectives.

Methods

Using a concurrent multiple baseline design, two autistic preschoolers with receptive language impairment were taught to identify 30 common objects. MtS, prompting, and reinforcement procedures were individualized to support each child. Maintenance checks and generalization probes were completed after a predetermined number of intervention sessions (i.e. three or four clinic sessions). A social validity questionnaire was completed by parents following the final maintenance check.

Results

Receptive object identification improved significantly for both participants. Despite exposure to vocabulary targets for only three or four sessions, they generalized the vocabulary targets to non-identical pictures and maintained words at maintenance checks. Participants were most successful when researchers individualized prompting and reinforcement.

Conclusion

MtS, prompting, and reinforcement were effective procedures for improving object identification, even with a limited number of intervention sessions. To support varying learner profiles, modifying prompting and reinforcement procedures was necessary. Caregivers of both participants reported positive improvements in areas such as communication, attention, and behaviors.

Implications

This replicated study provides support for MtS, prompting, and reinforcement as means of teaching receptive vocabulary to autistic preschoolers in a clinical setting. The materials used were simple and cost-effective. Overall, this study outlines and supports a flexible and effective evidence-based practice to teach receptive language to autistic children.

Effect of observing response requirements to sample and comparison stimuli on the establishment of reject control (sample/S- relations)

The establishment of sample/S- relations (or reject control) during conditional discrimination training (AB, BC) affects transitivity (AC), equivalence (CA) and reflexivity (AA, BB, CC) test outcomes. The present study parametrically evaluated the effects of different observing patterns to comparison stimuli on the establishment of reject control during baseline conditional relation training. A matching-to-sample with observing requirements (MTS-OR) procedure was implemented during AB and BC conditional discrimination training. During training, the participants were required to observe the sample and incorrect comparison on every trial before responding. In addition, the participants were divided into three groups that differed regarding the percentage of training trials on which they were prevented from observing the correct comparison stimuli: 25%, 50%, and 75%. Once the mastery criteria were achieved during training, transitivity (AC), symmetry (BA, CB), equivalence (CA), and reflexivity (AA, BB, CC) tests were conducted with all comparison stimuli visible from the beginning. The results suggest that the number of errors during transitivity, equivalence, and reflexivity tests progressively increased as participants were prevented from observing the correct comparison on a greater number of trials during training. Symmetry test results, however, were not affected by the experimental manipulation. Moreover, the number of participants showing reject-control patterns during tests slightly increased and the number of participants showing select-control patterns decreased as a function of the number of trials on which the participants were prevented from observing the correct comparison. Thus, we suggest that observing patterns during training is a relevant variable that affects equivalence test outcomes.

Transfer of baseline reject control to transitivity trials and its effect on equivalence class formation

This study explored the role of baseline reject control on transitivity responding. In Experiment 1, participants learned to respond to a baseline of arbitrary AB and AC conditional relations, and then they were exposed to transitivity-like BC and CB trials in which the correct comparison stimulus was replaced by a novel stimulus (D). Five of 10 participants selected stimulus D, but only 1 showed expansion of the baseline stimulus classes to include the D stimuli. In Experiment 2, the emergence of symmetry and transitivity from baseline relations was assessed before participants were exposed to the transitivity-like trials. Six of 8 participants who showed emergence of equivalence relations selected the D stimuli on transitivity-like trials and provided evidence that baseline classes expanded to include these stimuli. In Experiment 3, these 6 participants selected novel stimuli (E) in additional transitivity-like trials, and all showed that the E stimuli had become members of the previously established classes, which now comprised 5 members. A route for the emergence of transitivity by way of the transfer of baseline between-classes reject control is discussed.