The effect of verbal and visual (color or black/white) coding strategies in self-paced instruction and test materials in facilitating student retention on different cognitive tasks was studied. The 176 college student subjects received instruction and testing using varied combinations of color or black/white materials. Instructional materials were a self-paced learning booklet with simple line drawings, word labels, and prose text on the human heart. Self-paced test materials measured four cognitive knowledge tasks. Color-coded, self-paced presentation materials were superior to black/white presentation materials on both immediate and delayed posttests; however, color presence in evaluation materials did not affect achievement. The effectiveness of color-coded instructional materials may result from the sustained student attention and content interaction they demand and the enhanced associative memory structure they provide. Color-coding had a more positive impact on visual than on verbal task tests. Recall decline from immediate to delayed retention testing was similar for both color-coding and black/white instructional groups. (LMM)