The participants in this study are junior and senior students enrolled in an undergraduate introductory instructional development course at a southwestern university. Students in the class were equally divided by visual ability into three treatment groups.

Results were not significant, concluding the effects of concretely illustrated and abstractly illustrated instruction for this study had no differential effect on learning abstract concepts. This finding points to further study with more proven instruments.

The design of the study used a two by three multivariate analysis of variance (MANOVA). The illustration variable had three levels: none, concrete and abstract. The dependent variables were immediate and delayed post-test scores.

The materials of this study were three versions of a printed lesson based on the intellectual skills portion of Gagne's domains of learning outcomes. The first treatment contained text and abstract visuals, the second treatment contained text and concrete visuals and the third was text alone. An immediate and delayed test was given over the lesson.

The purpose of this study was to investigate the comparative effects of concretely illustrated instruction versus abstractly illustrated instruction on the acquisition of abstract concepts with immediate and delayed testing.