Mayer, R. E., Steinhoff, K. et al. (1995). A generative theory of textbook design: Using annotated illustrations to foster meaningful learning of science text. Journal of Technology Research and Development, 43(1), 31-43.

In three experiments, college students read a text explaining how lightning works and then took problem-solving transfer tests. Some students (integrated group) also viewed illustrations depicting the major stages in the formation of lightning that (a) were placed adjacent to corresponding text paragraphs and (b) contained annotations repeating the verbal cause-and-effect information from the text. Other students (separated group) viewed the same illustrations (a) on a separate page and (b) without annotations, after they had finished reading the text. The integrated group generated approximately 50% more creative solutions on transfer problems than the separated group, and this pattern was stronger for students who lacked experience in meteorology than for high-experience students. The positive effects of integrated illustrations depended on incorporating annotations (i.e., captions and labels) into the illustrations rather than placing illustrations close to corresponding paragraphs. Results were interpreted in light of a generative theory of multimedia learning which posits that meaningful learning requires constructing connections between visual and verbal representations of a system.