We often assume that is the preferred mode for presenting graphics about how things work, but the existing research literature does not offer strong support for this assumption. Thus write Richard Mayer, Mary Hegarty, Sarah Mayer, and Julie Campbell in the December 2005 issue of Journal of Experimental Psychology: Applied. The researchers decided to investigate the relative efficacy of computer-animated presentations versus static presentations. Of course, in a design project, it is always possible to design in one medium well and in another medium poorly, so the researchers attempted to equalize the quality of the presentations: The animation and narration materials were constructed by using relevant principles of multimedia design for dynamic media, such as presenting the words as spoken rather than printed text (the modality principle) and presenting corresponding words and animations at the same time (the temporal contiguity principle). The illustrations and printed text materials were also constructed using relevant principles of multimedia design for static media, such as presenting the illustrations as a series of frames depicting the major steps in the process (the segmenting principle) and presenting corresponding words near the diagrams they described (the spatial contiguity principle). The researchers generated arguments for why each form of presentation should be more effective. For example, the static media presentations should work better because learners see only the frames that distinguish each major step. On the other hand, the dynamic media presentations should work better because they're more interesting to learners. The presentations occurred in four separate experiments with four different groups of college students. The average SAT scores in the four groups ranged from 1138 to 1230. Drawn from a pool of people who were satisfying part of a psychology course requirement, the groups contained many more women (137) than men (36), although Mayer noted that there was no sign of a different pattern of results for males. Each group saw a single presentation. The four presentations explained how lightning works, how a toilet works, how ocean waves are formed, and how an automobile brake works. After the presentation, the subjects were asked a retention question or a series of short retention questions (e.g., What causes the formation of ocean waves? Why do they move toward the shore? Why do they break at the shore?). They were also asked a series of transfer questions (e.g., Why do waves rise and curl? Why do they fall? If waves keep moving to the shore, why doesn't the ocean run out of water? What could you do to make sure waves break about 50 feet from the shore?). All questions were answered in writing. For all four presentations, groups that received the static presentation scored higher on both the retention and transfer tasks than groups that received the dynamic presentation. For two of the four presentations, the differences were statistically significant for retention, and for the other two, they were significantly different for transfer: waves and brakes were significant for retention; lightning and toilets, for transfer. However, the odds of all four static presentations being consistently higher on the retention and transfer questions are quite small. The study has some fairly severe limitations, some of which the authors recognize. For example, animation might be needed to explain more complicated systems than the four used in the experiment. People might not be able to keep track of everything in a complex system when it is presented in a series of static images. Similarly, animation might help in visualizing processes not visible in the real world, such as the movement of air around pressure systems (or, I would add, the structure of an atom or the universe). Learning from dynamic presentations might also be improved if the presentation arrived in meaningful segments, with the learner in control of movement from one segment to another (the famous hit continue when ready option). …