Learning of writing letter-like sequences in children with physical and multiple disabilities

This study compared implicit and explicit learning instructions in hand writing. Implicit learning is the ability to acquire a new skill without a corresponding increase in knowledge about the skill. In contrast, explicit learning uses declarative knowledge to build up a set of performance rules that guide motor performance or skills. Explicit learning is dependent on working memory, implicit learning is not. Therefore, implicit learning was expected to be easier than explicit learning in children in special education, given their expected compromised working memory. Two groups of children (5-12 years) participated, children in special education with physical or multiple disabilities (study group, n=22), and typically developing controls (n=32). Children learned to write letter-like patterns on a digitizer by tracking a moving target (implicitly) and verbal instruction (explicitly). We further tested visual working memory, visual-motor integration, and gross manual dexterity. Learning curves were similar for both groups in both conditions; children in the study group did learn both implicitly and explicitly. Motor performance was related to the writing task. In contrast to our hypothesis, visual working memory was not an important factor in the explicit condition. These results shed new light on the conceptual difference between implicit and explicit learning, and the role of working memory therein.