Verbal and visual instruction with mental retardation: The role of subject characteristics and task factors

Past research and theory presents an inconsistent picture concerning the relative value of verbal versus visual instructional programs for individuals with mental retardation. From an empirical perspective, there is evidence that this inconsistency may be due to the differences in the type of tasks and the specific abilities of the subjects employed across studies. In this research, the effects of three instructional procedures (verbal, visual, and verbal plus visual) were evaluated with mentally retarded persons who varied in verbal and visual ability. Performance was examined on a visual task which incorporated stimuli of varying degrees of familiarity to the subjects. The results indicated that the use of the combined verbal-visual instruction procedure was more effective than the other two training programs when task stimuli were familiar to the subjects. When task stimuli were unfamiliar, instructional procedures which had a visual component were found to be superior to a procedure which employed only the use of verbal component. The subjects' visual ability was most strongly associated with performance outcome when visual instruction was employed and unfamiliar task stimuli were sorted. In contrast, subjects' verbal ability appeared to be equally important across instructional and task conditions. The implications of the results for the design of instructional programs and for future research are discussed.