Do adults with mental retardation show pictorial superiority effects in recall and recognition?

We examined memory for pictures and words in adults with mental retardation and a control group of adults of normal intelligence. During acquisition, sets of simple line drawings and matching words were presented for study using an intentional learning procedure. The principle dependent measures were free recall and recognition. Measures of working memory span were also administered. Pictorial superiority effects occurred in free recall and recognition for both intelligence-level groups. Correlational analyses indicated that working memory span was primarily related to recall performance, irrespective of stimulus format. These data strongly suggest that persons with mental retardation can utilize nonverbal memory codes to support long-term retention as effectively as do adults of normal intelligence.