Procedures for teaching appropriate gestural communication skills to children with autism.

Four children with autism were taught to use gestures in combination with oral communication. Using a multiple-baseline across-responses design, intervention was introduced successively across three response categories containing gestures representative of attention-directing/getting, affective, and descriptive behavior. Although none of the participants displayed appropriate gestural and verbal responses during baseline, all participants acquired this skill with the systematic implementation of modeling, prompting, and reinforcement. Generalization measures indicated that the children learned to respond in the presence of novel stimuli and a novel setting. Social validity measures revealed that the participants' behavior appeared more socially appropriate at the completion of the study than at the start of the study, and that the participants' behavior was indistinguishable from that of their typically developing peers.

Maintained nodal-distance effects in equivalence classes.

Twelve subjects were trained to select one of two stimuli from a pair (the B pair) when presented with one of two stimuli from another pair (the A pair), thus establishing two AB relations, A1-B1 and A2-B2. In a similar fashion, additional stimuli were used to establish BC, CD, and DE relations. Trials used to train all relations occurred in each session. Once performances were established, probe trials were introduced that tested for the emergence of untrained relations (e.g., B1-D1 or A1-E1). These emergent relations were categorized according to nodal distance (i.e., the number of stimuli across which transitivity would have to hold in order for the relation to emerge). For example, a test for A2-C2 crosses one node (B2), whereas a test for A1-E1 crosses three nodes (B1, C1, and D1). Only 2 of the subjects formed equivalence classes. The evocation of class-appropriate responding by each emergent-relation probe was an inverse function of nodal distance for all 12 subjects. In addition, performance on the originally trained relations was disrupted by the introduction of probes. The 2 subjects who exhibited equivalence classes were then trained to make different numbers of key presses in the presence of each of the four A and E stimuli. In a response-transfer test, the B, C, and D stimuli evoked the responses trained to the A and E stimuli in the same equivalence class. Likelihood of class-appropriate responses was an inverse function of nodal distance, and this pattern persisted across testing. Reaction times in the transfer test were an inverted U-shaped function of nodal distance. Because training of the baseline relations occurred concurrently and the B, C, and D stimuli were presented an equal number of times before the transfer test, the test performances illustrate effects of nodal distance that were not confounded by order or amount of experience with the stimuli. The results imply that ordered, sequential exposure to individual stimulus relations may facilitate the development of equivalence classes and that the relatedness of stimuli within an equivalence class is a relatively permanent inverse function of nodal distance.

The effects of schedules of reinforcement on instruction-following in human subjects with verbal and nonverbal stimuli.

The experiment reported here represents a partial replication of an experiment by Newman, Buffington, and Hemmes (in press) and analyzes responding in college students as a function of three different schedules of reinforcement (FR 1, FR 2, FR 3) and either verbal discriminative stimuli (instructions) or nonverbal discriminative stimuli (different colored cards). All consequences (tokens) were based on behavior consistent either with the verbal discriminative stimulus (S(D)) or with the nonverbal S(D). The schedule of reinforcement varied across subjects, and accuracy of the verbal and nonverbal S(D)s varied across phases from. Results showed that the behavior of all continuous reinforcement (FR 1) subjects was sensitive to the accuracy of the verbal S(D)s, but the behavior of subjects in the nonverbal S(D) conditions showed more sensitivity than the behavior of subjects in verbal conditions under intermittent schedules (FR 2 and FR 3). These finding suggest that the behavior of subjects in experiments where instructions are sometimes pitted against actual contingencies of reinforcement is a function not only of the instruction, but also of the type of reinforcement schedule used.

Maximization of reinforcement by two autistic students with accurate and inaccurate instructions.

The present study examines maximization of reinforcement by two autistic individuals under conditions of no instructions, accurate instructions, and inaccurate instructions. Accuracy of instructions and magnitude of reinforcement for differential responding in a choice paradigm were systematically varied across phases. Subject one maximized reinforcement across all three conditions in seven experimental phases. Subject two maximized across these same seven phases, but also experienced three additional phases. In two of the additional phases, subject two maximized reinforcement. In a ninth phase, when reinforcement was intermittent rather than continuous, he failed to maximize reinforcement. Implications of the results for the controversies surrounding the concept of rule-governed behavior are discussed.