This application seeks support to continue long standing, programmatic research on stimulus control development in individuals who have severe, lifelong learning problems. The research has two major aims: (1) to further understanding of basic stimulus control processes in learning and (2) to improve methodology for teaching and evaluating individuals whose limited language skills render them difficult or impossible to teach with traditional instructional methods. The program emphasizes studies with children who are being treated in residential setting to prepare them for life in the community. Research under past NICHD sponsorship has developed operant conditioning methods capable of teaching substantial new behavior to people with severe intellectual disabilities. Among these are: (a) stimulus control shaping methods (stimulus fading, delayed cue, etc.); (b) prompting methods that make use of generalized stimulus relations (e.g., learning by exclusion); (c) methods for developing and evaluating stimulus classes based on common physical features; and (d) methods for developing arbitrary stimulus equivalence, including constructed response matching to sample with components of complex stimuli. During the current grant period (8/1/89 to present), research sought to blend the techniques into a comprehensive methodology for teaching behavioral prerequisites for rudimentary reading, spelling, and number skills to people with moderate to severe disabilities. The present application proposes to pursue this goal further, investigating novel approaches to problems identified under the current program and extending the program to study problems pertinent to clinical and educational applications of the methodology. Seven research projects and three core units are proposed. Projects 1-4 continue and expand studies begun during the current grant period. Projects 5-7 are extensions of past efforts that ask, respectively, whether behavioral programming based on our research (a) may require specific modifications in relation to the diagnostic status of the learner; (b) will prove useful in establishing and evaluating selection- based communication skills in individuals with severe communication deficits; and (c) will effectively promote gains in adaptive functioning in our study population. The core units provide support services that are critical to accomplishing the research program. These are (a) program direction and general project management, (b) technical support and statistical consulting, and (c) subject acquisition, evaluation, performance remediation, and tracking.