The investigation compared the transparency of 11 different types of symbols with 40 nonspeaking mentally retarded subjects (ages 4-20). Analysis indicated a hierarchy of difficulty with actual objects the easiest and Blissymbols and written words the hardest to understand. Results have implications for selecting initial symbol systems for…

Used descriptive analysis and a forced choice task to investigate childrens' and adults' production, interpretation, and judgment of notation. Results showed that young children may not impose the same symbol-meaning structure at decoding that was proposed at encoding. Only after this ability develops does a preference for one form-one function…