MOTIVATING AUTISTIC CHILDREN THROUGH STIMULUS VARIATION

This study evaluated the differential effectiveness of two methods of presenting discrimination tasks when teaching autistic children. In a constant task condition, the common method of presenting a single task throughout a session was used. In a varied task condition, the same task was interspersed with a variety of other tasks from the children's clinic curricula. Results showed declining trends in correct responding during the constant task condition, with substantially improved and stable responding during the varied task condition. In addition, naive observers judged the children to be more enthusiastic, interested, happier, and better behaved during the varied task sessions. These results suggest that “boredom” may be a particularly important variable to control in the treatment of autistic children, and that particular care may be necessary when defining criteria for task acquisition. The results are discussed in relation to the literature on increased responsivity to stimulus novelty and variation.     

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.     

Note on computation of bi-serial correlations in item evaluation

By the use of an algebraic variant of the ordinary formula for bi-serial correlation, tables, and graphic devices, a time-saving systematic procedure for the computation of bi-serial correlation co-efficients is outlined for application to the evaluation of items of a test. A table of z for arguments ofp=.000 top=.999 is given.     

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.     

International publication trends of JABA authorship

The present study addressed international publication trends in JABA authorship between 1970 and 1999. First, we analyzed authorship patterns to identify trends in the appearance of new first authors, unfamiliar authors, and frequent contributors. Second, articles were assigned to either a North American or an international category. The data show a decline in the number of articles by new authors and an increase in the publications of frequent contributors from North America. Trends are shown in comparison to those from the American Journal on Mental Retardation.     

A program to compute McGraw and wong’s common language effect size indicator

McGraw and Wong (1992) have described a very appealing index of effect size that requires no prior knowledge of statistics to understand, which they termed CL, the common language effect size indicator. CL is the probability that a score randomly sampled from one distribution will be larger than a randomly sampled score from a second distribution. McGraw and Wong describe how to compute CL from the means and standard deviations of two groups, using tables of normal curve probability values. The program described herein computes CL without lookup tables but also permits the user to compute CL from Cohen’s d, from a t test for independent groups, or from point-biserial r, the correlation between a dichotomous and a continuous variable. A table giving CL for various values of d is also provided, as are the equations for converting t and r to d.     

Communality of videogame performances with tracking tasks

Performances on three videogames were compared with two different tracking tasks and a third dual tracking task, after stability of performance was achieved by 40 male subjects. The six tasks were performed in succession for three weeks each, and one year separated administration of the tracking tasks from the videogames. Convergence of the cross-correlations among these tasks occurred such that higher correlations were attained for scores obtained late in practice (late/late) of two tasks (even when they were performed a year apart) rather than for scores obtained earlier in training (viz., early/early). High communality between these two types of tasks was observed as indicated by virtual overlap between the videogames and the tracking tasks, even though different control media (joysticks, knobs), control orders (zero/first), and control inputs (displacement/force transducer) were required. Because these tasks apparently index similar abilities, there may be advantages to measuring tracking skills with videogames, which include low cost, wide availability, inherent interest to subjects and motivation, rapid approach to stable levels, and, in many cases greater apparent face validity relative to real world performance requirements.