Comparison of Constant Time Delay and the System of Least Prompts in Teaching Chained Tasks.

This investigation compared the effectiveness and efficiency (sessions to criterion, percent of errors to criterion, and minutes of instructional time) of constant time delay and system of least prompts procedures in teaching chained tasks to students with moderate mental retardation. A different chained task was taught during each of two daily sessions, one task with constant time delay and the other with the system of least prompts. All four subjects learned 6 tasks; 3 with constant time delay and 3 with the system of least prompts. The parallel treatments design was used to assess the effects of the two instructional strategies. The results indicate that both strategies produced criterion level performance; however, the constant time delay proce dure was more efficient than the system of least prompts in terms of sessions, percent of errors, and direct instructional time to criterion. The differences were most pronounced on the measures of percent of errors and minutes of instructional time. The implications of these findings for practice are noted. Considerable research has shown that students with moderate to severe retardation dents with moderate retardation can learn (Doyle, Wolery, Ault, & Gast, 1988). The sys skills that allow them to function more indetern of least prompts involves presentation of pendently (Snell & Browder, 1987). Many a prompt hierarchy that is ordered from least skills needed for independent functioning into most intrusive. The student is initially gi volve response chains; examples in the doven the opportunity to perform a task inde mestic skill area include cooking, mending pendently; when an error or no response oc clothes, and cleaning clothes; examples in the curs, the student is provided with the next vocational area include janitorial skills, appaleast intrusive prompt. This process contin ratus assembly, and dishwashing. The system ues until the student responds correctly, of least prompts, also referred to as the inAnother instructional procedure that has creasing assistance procedure, has been used received research attention is time delay extensively for teaching such skills to stu(Handen & Zane, 1987). Time delay initially involves the simultaneous presentation of a target stimulus and a controlling response This investigation was supported by the U.S. De, , , i r ' . , r , prompt, and subsequently involves system partment of Education, Office of Special Educar . r . , . ' . tion and Rehabilitation Services, Field-Initiated atlc presentation of a response interval be Grant (Grant Number G008530197). However, tween the presentations of the target stimulus the opinions expressed do not necessarily reflect an(i prompt. Two types of time delay proce the policy of the U.S. Department of Education, dures exist: Progressive time delay, which in and no official endorsement of the U.S. Departvol ves inserting a progressively longer re ment of Education should be inferred. The ausponse interval between the target stimulus thors are grateful for the assistance provided by and the prompt; and constant time delay, Donald Cross, Ed.D., Chairperson, Department of which involves inserting a fixed response in Special Education, University of Kentucky; and by teryal between the stimu]us and pr0mpt. Dr. Norman Osborne and Mrs. Katye Jenkins of ^ , , , , rr • • . i • y-> ^ Time delay has been effective in teaching a Fayette County Public Schools. . r ,. . . . Correspondence concerning this manuscript varlety of d,screte responses to students with should be addressed to: Mark Wolery, Ph.D., Prinmoderate retardation (Ault, Wolery, Doyle, cipal Investigator CIS Project, Department of Spe& Gast, 1989). Comparisons of progressive cial Education, 229 Taylor Education Building, time delay and the system of least prompts in University of Kentucky, Lexington, KY 40506. teaching discrete responses has shown that