WHEN IS AN ILLUSTRATION WORTH 10000 WORDS

In three experiments, students read expository passages concerning how scientific devices work, which contained either no illustrations (control), static illustrations of the device with labels for each part (parts), static illustrations of the device with labels for each major action (steps), or dynamic illustrations showing the "off" and "on" states of the device along with labels for each part and each major action (parts-and-steps). Results indicated that the parts-and-steps (but not the other) illustrations consistently improved performance on recall of conceptual (but not nonconceptiual) information and creative problem solving (but not verbatim retention), and these results were obtained mainly for the low prior-knowledge (rather than the high prior-knowledge) students. The cognitive conditions for effective illustrations in scientific text include appropriate text, tests, illustrations, and learners.