The influence of task variation and maintenance tasks on the learning and affect of autistic children

Analyses of autistic children's learning and affect have begun to consider the role of antecedent variables, including the manner with which tasks are sequenced within instructional sessions. Within the context of a simultaneous-treatments design, this experiment evaluated autistic children's affect and rate of task acquisition under three experimental conditions. The conditions were (1) a constant task condition in which only one acquisition task was presented per session; (2) a varied-acquisition-task condition, in which 10 acquisition tasks were randomly interspersed throughout each session; and (3) a varied-with-maintenance-task condition, which randomly interspersed 5 acquisition tasks and 5 which had been previously acquired. The results showed significantly more efficient learning under the varied-maintenance condition, with no consistent differences separating the other two conditions. In addition, observers' ratings of the children's affect showed that the most positive judgments were produced by the varied-maintenance condition. The varied-acquisition condition was next while the constant task condition always produced the least favorable ratings. These findings are discussed in relation to the literature on massed versus distributed practice, stimulus variation, and success-induced motivation. The implications for upgrading the treatment and education of handicapped children are also reviewed.     

The generality of overselectivity in developmentally disabled children

A growing body of research suggests that low Mental Age (MA) autistic and retarded children show a unique stimulus control deficit, one that may cause many or most of their behavioral deficiencies. This problem, stimulus overselectivity, is evidenced when a child responds only to a restricted portion of the stimulus environment when compared with normal children. The purpose of this study was to assess whether this overselectivity is general across situations or whether it is restricted to certain stimulus/task conditions. Eight autistic children, who evidenced overselectivity on a preassessment task, and 8 normal children with similar MA levels participated. All children were trained on 3 tasks to determine if overselectivity varied as a function of different stimulus conditions. Each of the 3 tasks involved training a child to respond to (i.e., touch) a card containing a circle (S +) and to avoid a blank (S ?) card. In each case, the circle comprised a series of dots. The difference between the 3 circles (tasks) was the distance between the successive dots making up each circle. Also, in the minimal separation condition the dots were smaller in size and greater in number than in the larger separation conditions. Of concern was whether autistic children learned about the gestalt (i.e., the circle), which required attention to multiple cues, or whether children would overselect and respond to the dots. The results showed that (1) stimulus overselectivity was found not to be a generalized deficit in autistic subjects; instead, it varied as a function of the stimulus variables; and (2) the stimulus variables manipulated in this study similarly influenced the responding of both normal and autistic children. The implications of these data for a theory of overselectivity are discussed.     

NORMAL PEER MODELS AND AUTISTIC CHILDREN'S LEARNING

Present research and legislation regarding mainstreaming autistic children into normal classrooms have raised the importance of studying whether autistic children can benefit from observing normal peer models. The present investigation systematically assessed whether autistic children's learning of discrimination tasks could be improved if they observed normal children perform the tasks correctly. In the context of a multiple baseline design, four autistic children worked on five discrimination tasks that their teachers reported were posing difficulty. Throughout the baseline condition the children evidenced very low levels of correct responding on all five tasks. In the subsequent treatment condition, when normal peers modeled correct responses, the autistic children's correct responding increased dramatically. In each case, the peer modeling procedure produced rapid achievement of the acquisition criterion which was maintained after the peer models were removed. These results are discussed in relation to issues concerning observational learning and in relation to the implications for mainstreaming autistic children into normal classrooms.     

Learning through observation: The effects of peer modeling on acquisition and generalization in autistic children

The purpose of this study was to systematically determine whether lowfunctioning autistic children [MA of approximately half of their CA or less] could learn through observation by the use of a peer modeling procedure. Since modeling is less structured than traditional one-on-one procedures, it was also thought that modeling might facilitate subsequent generalization of tasks learned through observation. Four autistic children were taught two receptive labeling tasks. One task was taught by a traditional trial and error procedure, while the other task was taught by a modeling procedure wherein the models were other autistic children. Results indicated that all four children learned through observation of their peer model. Additionally, generalization and maintenance of correct responding were superior when the children learned through observation rather than by trial and error. These results are discussed in terms of the modeling literature, generalization issues, and implications for designing teaching settings for autistic children.This research was supported by USPHS Research Grants MH 28231 and MH 29210 from the National Institute of Mental Health. The authors would like to acknowledge Paul Lizotte for his assistance.     

Classroom treatment of autistic children: II. individualized instruction in a group

This study was designed to assess the feasibility of providing individualized instruction in a classroom of autistic children. In particular, we investigated whether students' unsupervised responding was a variable which would influence the effectiveness of individualized instruction procedures. Initially, one teacher attempted to teach different academic behavior to four autistic children simultaneously. During these sessions the teacher rotated from child to child, providing individualized instructions and reinforcers to each. We found, however, that each child stopped responding whenever the teacher rotated to a different child and, further, no academic progress occurred for any of the children during these sessions. In a multiple baseline design, treatment procedures were then introduced (prompt fading, chaining, and programmed instructional materials) to teach each student to continue working for an extended period of time after each instruction from the teacher. After treatment, sessions of individualized instruction in a group were reintroduced for each child. The results showed that unsupervised responding was an important variable influencing the effectiveness of individualized instruction. Specifically, the data show that (1) unsupervised responding, acquired during treatment, generalized to the group setting; (2) after treatment, each child began to make progress on his assigned tasks; and (3) programming instructional materials in small steps appeared to be necessary in order to ensure the maintenance of unsupervised responding across changes in instructional materials. By the end of this study it was possible for one teacher to simultaneously teach four autistic children — with each child learning at his own rate, on his own task, with minimal supervision from the teacher. It is suggested that the generalizability of these results, to other settings where continuous supervision is difficult, may be an important concern of future research.     

SELF-STIMULATION AND LEARNING IN AUTISTIC CHILDREN: PHYSICAL OR FUNCTIONAL INCOMPATIBILITY?1

This study investigated whether an observed inverse relationship between self-stimulation and learning in autistic children is due to a physical inability of the subject to use the same body part for self-stimulation and task responding, or whether self-stimulation “distracts” the subject from task responding. Four actively self-stimulating autistic children were taught two discrimination tasks; one required a response that physically interferred with their self-stimulation; the other did not. Results were: (a) all subjects responded similarly across both tasks; (b) the three subjects with higher mental age scores learned both tasks without external suppression of self-stimulation; and (c) none of the subjects showed an inverse relationship between self-stimulation and learning. The study demonstrated that elimination of self-stimulation is not a necessary prerequisite for the acquisition of a new behavior in all autistic children.     

TOO MUCH REINFORCEMENT,TOO LITTLE BEHAVIOR: ASSESSING TASK INTERSPERSAL PROCEDURES IN CONJUNCTION WITH DIFFERENT REINFORCEMENT SCHEDULES WITH AUTISTIC CHILDREN

Task interspersal procedures have been quite effective in increasing autistic children's motivation to learn. These procedures have typically demonstrated that the inclusion of reinforced maintenance tasks (previously learned tasks) increases responding to new acquisition tasks because more reinforcers, in general, are available. However, studies have not specifically addressed the effects of various schedules of reinforcement, used in conjunction with task interspersal procedures, upon response acquisition. In the present study, a multiple baseline design across subjects was used to assess different reinforcement schedules. Five autistic children participated in learning sessions, during which trials of an acquisition task were interspersed with trials of three maintenance tasks. Correct responses to acquisition tasks were continuously reinforced throughout all conditions, while the reinforcement schedule for competent performance of maintenance tasks differed systematically. Results indicated that all children learned the new tasks when food reinforcers were presented only for acquisition tasks. Results are discussed in terms of behavioral contrast and improving the effectiveness of motivation-enhancing procedures for autistic children.     

A COMPARISON OF PEER-INITIATION AND TEACHER-ANTECEDENT INTERVENTIONS FOR PROMOTING RECIPROCAL SOCIAL INTERACTION OF AUTISTIC PRESCHOOLERS

We compared two procedures for improving the social interactions of three autistic children. In a peer-initiation condition, confederates were taught to initiate interaction with the autistic children. In a teacher-antecedent condition, teachers prompted the autistic children to initiate with confederates, who had been taught to reciprocate. Using an alternating treatment design, differential effects were found. The peer-initiation procedure reliably increased the social responses of the autistic children, whereas the teacher-antecedent condition increased the initiations and responses of the autistic children. In addition, longer chains of social interaction occurred during the teacher-antecedent condition.     

The effects of constant vs varied reinforcer presentation on responding by autistic children

The autistic child's characteristic lack of motivation can create considerable problems for educators. Since there is some evidence that stimulus variation may influence motivation, this study was designed to assess the differential effects of constant vs varied reinforcer presentation. Specifically, two questions were addressed: (1) Would there be any differences in the total number of responses emitted by autistic children when the reinforcer was held constant as opposed to varied; and (2) would there be any differences in the interresponse interval for constant vs varied reinforcer presentation? The results clearly demonstrated that the children in this investigation made significantly more and faster responses when the reinforcer presentation was varied as opposed to constant. The results are discussed in terms of the effects of stimulus variation on satiation and implications for teachers of autistic children.     

Instrumental learning in preschool children as a function of type of task, type of reward, and some organismic variables

The effects on instrumental behavior of differences in type of task, type of reward and three organismic variables were investigated in preschool children. The main results were that: (a) an imitative task was acquired in fewer trials than a nonimitative task; (b) social reward in acquisition led to greater resistance to extinction; (c) a history of frequent social reinforcement from peers led to persistence in responding during extinction for boys only; (d) extraversion was found to interact with the variables of task and reward in errors made during extinction; and (e) intelligence was not found to be a reliable predictor of main acquisition and extinction measures or related errors. Detailed analysis of the different types of errors contributed directly to the interpretation of these findings.     

Novel n-back spatial working memory task using eye movement response

We created a novel eye movement version of the n-back task to measure spatial working memory (WM). Rather than one continuous trial, discrete trials were presented in order to develop a simpler WM task. In Experiment 1, we varied the visibility of the final stimulus to maximize the difference in performance between 0-back and 1-back tasks (WM effect). In Experiment 2, we administered the optimized task to children. In Experiment 3, we further simplified the task. Both adults and children easily completed our task, displaying significant WM effects. Further, similar WM effects were obtained in our original and simplified n-back spatial WM tasks, demonstrating flexibility. Because WM deficits are often an early feature of disease and a marker of disease progression, our saccadic measure of spatial WM may be particularly useful in hard-to-test populations, such as patients and children, and may have application in brain-imaging studies that require discrete trials.     

INCREASING THE INDEPENDENT RESPONDING OF AUTISTIC CHILDREN WITH UNPREDICTABLE SUPERVISION

We investigated the role of predictable versus unpredictable supervision on the independent task responding of three autistic children. In a predictable supervision condition, the therapist was present in the setting for a regular period of time and then was absent for the remainder of the session. In an unpredictable supervision condition, the therapist's presence was scheduled on a random, intermittent, and unpredictable basis throughout the session. The multiple baseline analysis showed that the unpredictable supervision produced much higher levels of on-task responding during the therapist's absence for all three children. Analysis of work completed during the therapist's absence also favored the unpredictable supervision condition. The results are discussed in relation to the literature on generalization and educational practice.     

THE LIMITS AND MOTIVATING POTENTIAL OF SENSORY STIMULI AS REINFORCERS FOR AUTISTIC CHILDREN

This study investigated the reinforcing properties, limits, and motivating potentials of sensory stimuli with autistic children. In the first phase of the study, four intellectually retarded autistic children were exposed to three different types of sensory stimulation (vibration, music, and strobe light) as well as edible and social reinforcers for ten-second intervals contingent upon six simple bar pressing responses. In the second phase, the same events were used as reinforcers for correct responses in learning object labels. The results indicated that: (a) sensory stimuli can be used effectively as reinforcers to maintain high, durable rates of responding in a simple pressing task; (b) ranked preferences for sensory stimuli revealed a unique configuration of responding for each child; and (c) sensory stimuli have motivating potentials comparable to those of the traditional food and social reinforcers even when training receptive language tasks.     

THE EFFECTS OF ECHOLALIA ON ACQUISITION AND GENERALIZATION OF RECEPTIVE LABELING IN AUTISTIC CHILDREN

This investigation, consisting of two experiments, was designed to assess the effects of autistic immediate echolalia on acquisition and generalization of receptive labeling tasks. Experiment 1 addressed whether autistic children could use their echolalia to facilitate acquisition. The results indicated that incorporating echolalia (echo of the requested object's label) into the task before manual response (handing the requested object to the experimenter) facilitated receptive labeling. Experiment 2 was designed to determine the effects of incorporating echolalia into task response on acquisition and subsequent generalization. These results indicated that echolalia facilitated generalization for echolalic autistic children but not for functionally mute autistic children. The results of the experiments are discussed in terms of stimulus control. Additionally, it is proposed that perhaps in certain cases, echolalia should not be eliminated, but used to advantage in receptive responding.     

REINFORCER VARIATION: IMPLICATIONS FOR MOTIVATING DEVELOPMENTALLY DISABLED CHILDREN

Motivating developmentally disabled children to participate in educational activities can be very difficult. This is especially true for children diagnosed autistic. Because there is some evidence to suggest that stimulus variation may influence motivation, the present study investigated the effects of constant vs. varied reinforcer presentation on correct responding and on-task behavior. Results from a reversal design showed declining trends in both correct responding and on-task behavior when the same reinforcer was consistently presented, whereas, varying the reinforcers produced significantly improved and stable responding. The results are discussed in relation to the literature on stimulus variation and its effects on responsivity.     

Categorization of multidimensional stimuli by pigeons

Six pigeons responded in a visual category learning task in which the stimuli were dimensionally separable Gabor patches that varied in frequency and orientation. We compared performance in two conditions which varied in terms of whether accurate performance required that responding be controlled jointly by frequency and orientation, or selectively by frequency. Results showed that pigeons learned both category tasks, with average overall accuracies of 85.5% and 82% in the joint and selective control conditions, respectively. Although perfect performance was possible, responding for all pigeons fell short of optimality. Model comparison analyses showed that the General Linear Classifier (GLC; Ashby, 1992) provided a better account of responding in the joint control condition than unidimensional models, but a unidimensional model fitted better for the condition that required selective control by frequency. Our results show that pigeons' responding in a visual categorization task can be controlled jointly or selectively by stimulus dimensions, depending on reinforcement contingencies. However, analysis of residuals confirmed that systematic deviations of GLC predictions from the obtained data were present in both conditions, suggesting that an alternative account of responding in multidimensional category learning tasks may be necessary.     

Heterogeneity impairs numerical matching but not numerical ordering in preschool children

Do preschool children appreciate numerical value as an abstract property of a set of objects? We tested the influence of stimulus features such as size, shape, and color on preschool children's developing nonverbal numerical abilities. Children between 3 and 5 years of age were tested on their ability to estimate number when the sizes, shapes, and colors of the elements in an array were varied (heterogeneous condition) versus when they did not vary (homogeneous condition). One group of children was tested on an ordinal task in which the goal was to select the smaller of two arrays while another group of children was tested on a match‐to‐sample task in which the goal was to choose one of two visual arrays that matched the sample in number. Children performed above chance on both homogeneous and heterogeneous stimuli in both tasks. However, while children showed no impairment on heterogeneous relative to homogeneous arrays in the ordering task, performance was impaired by heterogeneity in the matching task. We suggest that nonverbal numerical abstraction occurs early in development, but specific task objectives may prevent children from engaging in numerical abstraction.     

INTERTRIAL INTERVAL DURATION AND LEARNING IN AUTISTIC CHILDREN

This study investigated the influence of intertrial interval duration on the performance of autistic children during teaching situations. The children were taught under the same conditions existing in their regular programs, except that the length of time between trials was systematically manipulated. With both multiple baseline and repeated reversal designs, two lengths of intertrial interval were employed: short intervals with the S^D for any given trial presented approximately one second following the reinforcer for the previous trial versus long intervals with the S^D presented four or more seconds following the reinforcer for the previous trial. The results showed that: (1) the short intertrial intervals always produced higher levels of correct responding than the long intervals; and (2) there were improving trends in performance and rapid acquisition with the short intertrial intervals, in contrast to minimal or no change with the long intervals. The results are discussed in terms of utilizing information about child and task characteristics in terms of selecting optimal intervals. The data suggest that manipulations made between trials have a large influence on autistic children's learning.     

Recollection reduces unitised familiarity effect

Two types of encoding tasks have been employed in previous research to investigate the beneficial effect of unitisation on familiarity-based associative recognition (unitised familiarity effect), namely the compound task and the interactive imagery task. Here we show how these two tasks could differentially engage subsequent recollection-based associative recognition and consequently lead to the turn-on or turn-off of the unitised familiarity effect. In the compound task, participants studied unrelated word pairs as newly learned compounds. In the interactive imagery task, participants studied the same word pairs as interactive images. An associative recognition task was used in combination with the Remember/Know procedure to measure recollection-based and familiarity-based associative recognition. The results showed that the unitised familiarity effect was present in the compound task but was absent in the interactive imagery task. A comparison of the compound and the interactive imagery task revealed a dramatic increase in recollection-based associative recognition for the interactive imagery task. These results suggest that unitisation could benefit familiarity-based associative recognition; however, this effect will be eliminated when the memory trace formed is easily accessed by strong recollection without the need for a familiarity assessment.     

Early bilingualism enhances mechanisms of false‐belief reasoning

In their first years, children's understanding of mental states seems to improve dramatically, but the mechanisms underlying these changes are still unclear. Such ‘theory of mind’ (ToM) abilities may arise during development, or have an innate basis, developmental changes reflecting limitations of other abilities involved in ToM tasks (e.g. inhibition). Special circumstances such as early bilingualism may enhance ToM development or other capacities required by ToM tasks. Here we compare 3‐year‐old bilinguals and monolinguals on a standard ToM task, a modified ToM task and a control task involving physical reasoning. The modified ToM task mimicked a language‐switch situation that bilinguals often encounter and that could influence their ToM abilities. If such experience contributes to an early consolidation of ToM in bilinguals, they should be selectively enhanced in the modified task. In contrast, if bilinguals have an advantage due to better executive inhibitory abilities involved in ToM tasks, they should outperform monolinguals on both ToM tasks, inhibitory demands being similar. Bilingual children showed an advantage on the two ToM tasks but not on the control task. The precocious success of bilinguals may be associated with their well‐developed control functions formed during monitoring and selecting languages.