Preference for multiple versus mixed schedules of reinforcement

Five pigeons were trained in a concurrent-chain procedure. In the initial links, equal nonindependent variable-interval schedules were available concurrently on two keys. Completing the schedule on either key led to exclusive presentation of one of two further variable-interval schedules for a fixed period of time. During these terminal links, as many reinforcers as were scheduled could be obtained. If the response producing this terminal link occurred on one key, differential stimuli signaled which variable-interval schedule had been produced. If the response producing the terminal link occurred on the other key, no such differential stimuli were available. Once the fixed period of time elapsed, the initial links were reinstated. In Experiment 1, the period of time for which the terminal links were available was always 10 s and the absolute duration of the initial links was varied. Subjects preferred the alternative leading to the multiple schedule when the initial-link duration was short, but preferred the alternative leading to the mixed schedule when the initial-link durations were longer. In Experiment 2, both the initial-link duration and the duration of the terminal links were varied. The effect of initial-link duration was identical to that in Experiment 1 and there was no systematic effect of varying the terminal-link duration.     

Training respite care providers for families with handicapped children: Experimental analysis and validation of an instructional package

We conducted four experiments to evaluate a respite care training package. In Experiment 1, we assessed the effectiveness of an instructional manual on the acquisition of respite care skills and compared the relative effects of three different manual on the acquisition of respite care skills and compared the relative effects of three different manual presentation formats. Results showed that performance during simulated (role-played) respite care situations improved substantially for all six trainees following presentation of the instructional manual (with no significant differences between presentation formats) although some remedial training was necessary to achieve mastery criterion. In Experiment 2, we evaluated the effects of the manual presented as a whole with a larger group of trainees and compared it to a workshop training approach. Results showed that both the instructional manual and workshop training approaches were effective, but that the former appeared to be more cost-effective. In both experiments, correct responding generalized to a respite care situation with a multiply handicapped child. In addition, several measures of social validity were obtained. In Experiment 3, we evaluated a simplified training and assessment package that could be conducted using the resources typically available to respite care agencies, and in Experiment 4, we demonstrated that respite care agency personnel could successfully implement this program.     

APPLICATIONS OF A SEQUENTIAL ALTERNATING TREATMENTS DESIGN

We propose the use of a combined version of the alternating treatments and multiple baseline designs in situations in which a traditional baseline (no treatment) condition either does not provide an adequate contrast condition or is not feasible or practical due to clinical constraints. We refer to this design as a sequential alternating treatments design because two treatments are initially implemented in a random or counterbalanced fashion and are followed by a sequential change in one or both treatments across settings, subjects, or tasks. The effects of the independent variables are assessed first by analyzing the two series of data points representing the different treatments (relative effects) and then by assessing changes in one or both series, as application of the alternative treatment is introduced sequentially. The sequential application of treatment provides an analysis of control in the same manner as the multiple baseline design; the initial alternating treatments phase provides a contrast condition in much the same manner as a baseline condition. Applications of this design to the assessment of peer training and self-injurious behavior are described.     

BEHAVIORAL MANAGEMENT OF EXERCISE TRAINING IN VASCULAR HEADACHE PATIENTS: AN INVESTIGATION OF EXERCISE ADHERENCE AND HEADACHE ACTIVITY

A behavioral package was used to shape and maintain the adherence of 5 subjects with vascular headache to a program of aerobic exercise training. Repeated measures of exercise behavior were examined through the use of a bidirectional changing criterion design. Repeated measures of headache activity were also collected. Results demonstrated a functional relationship between the behavioral package and exercise adherence, because all 5 subjects showed exercise behavior that matched bidirectional changing exercise criteria. The results also indicated clinically significant collateral reductions in vascular headache activity in 4 subjects. Subjects whose aerobic fitness levels were not masked by vasoactive medication also showed measurable increases in aerobic fitness. The results are discussed in terms of the methodology used to demonstrate a functional relationship between the adherence package and exercise behavior and the possible mechanism(s) by which aerobic exercise activity might affect vascular headache activity.     

An alternative test for multisample sphericity

A test for multisample sphericity based on the efficient scores criterion is obtained as an alternative to the likelihood ratio test developed by Mendoza.     

THE EFFECTS OF KNOWN-ITEM INTERSPERSAL ON ACQUISITION AND RETENTION OF SPELLING AND SIGHTREADING WORDS1

The use of well-documented procedures such as shaping, differential reinforcement, and fading may not be the most practical for teaching certain academic behaviors. An alternative procedure of interspersing trials on previously trained items with trials on unknown items has been suggested, but its effects on acquisition and retention have not been systematically examined. This study investigated the effects of interspersing known items during training on new tasks. Six mentally retarded adolescents were given pretests on spelling and sightreading words, which were divided into pools of learned and unlearned items. Training and baseline conditions were implemented concurrently, using a multi-element design. During interspersal training sessions, 10 known words from the pretest were alternately presented with each of 10 test words that were incorrect on the pretest. The ratio of previously mastered words to test words was gradually reduced. During baseline sessions, 10 different test words were presented without alternation of previously known words. During this condition, a procedure involving high-density social reinforcement contingent on task-related behaviors, but not necessarily correct responses, was later introduced, followed by a return to the original noninterspersal baseline. During all conditions, test words were deleted and replaced after meeting a mastery criterion of three consecutive correct trials. Retention tests were administered over learned test words for all conditions, at specified intervals. Results showed that both acquisition and retention of spelling and sightreading words were facilitated by the interspersal procedure. All subjects acquired more words during the interspersal condition than either the high-density or baseline conditions. The effectiveness of the procedure may possibly be attributed to better maintenance of attending behavior to unknown items as a function of the inclusion of known items, which directly increase the amount of reinforcement for correct responses during the early stages of skill acquisition.     

An experimental analysis of electricity conservation procedures

Daily electricity consumption of four families was recorded for 106 days. A reversal design, consisting of various experimental conditions interspersed between repeated baseline conditions, was used. During experimental conditions, daily prompts (written conservation slogans attached to front doors) and/or daily feedback (daily kilowatts consumed and daily cost information) were in effect. Maximum consumption occurred during the initial baseline; minimum consumption occurred during different experimental conditions for different families. The mean decrease from the maximum to the minimum for all families was 35%. Reversals in consumption were demonstrated in three families, although successive baselines tended to decrease. No clear differences in effectiveness between prompting and feedback conditions were apparent. The procedures used resulted in considerable dollar savings for the families.     

THE CHANGING CRITERION DESIGN

This article describes and illustrates with two case studies a relatively novel form of the multiple-baseline design called the changing criterion design. It also presents the design's formal requirements, and suggests target behaviors and circumstances for which the design might be useful.     

Univariate repeated measures techniques applied to multivariate data

Repeated measures designs in psychology have traditionally been analyzed by the univariate mixed model approach, in which the repeated measures effect is tested against an error term based on the subject by treatment interaction. This paper considers the extension of this analysis to designs in which the individual repeated measures are multivariate. Sufficient conditions for a valid multivariate mixed model analysis are given, and a test is described to determine whether or not given data satisfy these conditions.     

Contingency and stimulus change in chained schedules of reinforcement

Higher rates of pecking were maintained by pigeons in the middle component of three-component chained fixed-interval schedules than in that component of corresponding multiple schedules (two extinction components followed by a fixed-interval component). This rate difference did not occur in equivalent tandem and mixed schedules, in which a single stimulus was correlated with the three components. The higher rates in components of chained schedules demonstrate a reinforcing effect of the stimulus correlated with the next component; the acquired functions of this stimulus make the vocabulary of conditioned reinforcement appropriate. Problems in defining conditioned reinforcement arise not from difficulties in demonstrating reinforcing effects but from disagreements about which experimental operations allow such reinforcing effects to be called conditioned.