Using Time Delay to Teach Manual Signs to A Severely Retarded Student

Abstract

A severely retarded adolescent boy who had not acquired oral expression skills was taught five manual signs to express a food preference. Time delay procedure was used to present and fade both model and physical prompts. The food items themselves were used as reinforcers. A multiple baseline design employed across behaviors demonstrated that instruction was effective for all five signs. During probes for expression of choice, the subject did select a variety of food items.