Twenty student volunteers, naive to Blissymbols, were asked to “guess” the meaning of 64 Blissymbols, each presented without their word gloss. The symbols and their verbal labels were each varied orthogonally on two dimensions of representativeness of the symbol (high/low) and concreteness of the word they were designed to represent (high/low). The representativeness values were obtained from the norms reported by Yovetich and Paivio (1980), while the concreteness values were obtained from the norms reported by the Paivio, Yuille, and Madigan (1968). The subjects' responses were subsequently scored as either “exact/synonymous” or “other.” Results of the analysis of subjects' mean responses for the two dimensions of Blissymbols, using paired f-tests, revealed that the guessability of a symbol's gloss was significantly affected by the dimension of representativeness. The results have implications for understanding the psychological attributes of the graphic representations which are used in clinical and/or research methodologies, and they support the findings of earlier research dealing with Blissymbols as well as natural language logographs (i.e., Chinese and Japanese).