This investigation studied the transparency or guessability of communication symbols from three widely used systems—Blissymbols, Picsyms, and Rebus. Symbol transparency was assessed across four age groups through a forced-choice identification task which contained Word, Phrase, and Sentence subtests. Significant differences were found in both Word subtest and Total test scores for the variables of symbol system and chronological age. Subjects across all age groups performed similarly in response to the Picsyms and Rebus symbol items but significantly more poorly when identifying Blissymbols. In addition, there appeared to be a developmental progression for the Picsym and Rebus symbol tests, but the same trend did not emerge for the Blissymbol test. The feature of symbol transparency, as measured through a forced-choice identification task, discriminated among symbol systems. Significantly fewer symbols from the Bliss system were found to be transparent when compared with Picsym and Rebus systems.
