The lack of standardization in research involving pictorial variables has made it difficult to clarify the functions of pictorial stimuli in learning. This study sought to determine whether selected methods of rendering pictorial illustrations influenced the number and type of descriptive words evoked in a verbal association task. Normally the verbal responses evoked by a pictorial stimulus may be ranked as to frequency, with high frequency (called high dominance) associated with ease in learning. Experimental results indicated that color photographs elicited significantly more descriptive responses than black-and-white photographs, which in turn did better than line drawings. Both the stimulus objects were factors in determining the number and type of verbal responses elicited. The results affirm the need for developing standardized materials for studying concept learning with pictorial materials. (RB)