ABSTRACT
Explaining how things work is at the heart of science so our research focuses on techniques for helping students understand scientific explanations. In particular, we begin with texts that explain how various physical, mechanical, and biological systems work such as how lightning storms develop, how a car’s braking system works, or how a bicycle tire pump works. Verbal modes of instruction are dominant in education so the most common way of presenting scientific explanations is to use words—such as printed or spoken text. In our research, we explore the idea that adding visual modes of presentation—such as illustrations—can improve students’ understanding of scientific explanations. In a series of studies we have found that adding illustrations to text in a book-based environment can greatly improve students’ understanding of scientific explanations, as measured by performance on tests of problem-solving transfer. In addition, in our research we have pinpointed the conditions under which adding visual representations to text can help students to understand scientific explanations. Our work is guided by a cognitive theory of multimedia learning that assumes that there are separate verbal and visual information channels; that each channel is limited in processing capacity; and that constructivist learning occurs when students mentally select relevant verbal and visual material, mentally organize the selected material into verbal and visual mental models respectively, and mentally integrate the visual and verbal mental models with each other and with prior knowledge. It follows that an essential condition for effective multimedia instruction is that the learner be able to process corresponding visual and verbal material in working memory at the same time.
