Embedding Extra Stimuli in the Task Direction: Effects on Learning of Students With Moderate Mental Retardation

This investigation examined the acquisition of target and nontarget stimuli by 4 students with moderate mental retardation. Students were taught to name photographs of foods (target stimuli) using a progressive time delay procedure. In addition, the grocery departments where foods could be found in a local supermarket (nontarget stimuli) were presented as part of the discriminative stimulus. A multiple probe design across photographs and replicated across students was used to assess experimental control of both target and nontarget stimuli. The results indicated that (a) progressive time delay was effective in teaching 12 target photographs to 3 students and 6 photographs to 1 student, (b) presentation of the nontarget grocery department as part of the discriminative stimulus was effective in increasing the percentages of correct responding to these stimuli across all students, and (c) some generalization in the percentage of correct responding to the target and nontarget stimuli occurred in the natural supermarket setting.