Cognitive learning and textbook/handbook design

Similar to Carter, who Shamoon and Burns mention, composition researcher and theorist Janet Emig talks about how cognitive learning and our mastery of language progresses from novice to expert. These ideas got me thinking about the cognitive levels of readers, and wondering if the trend toward more graphically driven textbooks for undergraduates isn’t actually reinforcing the textbook’s demise. It’s not only the ideas about writing that are more simple in freshman composition textbooks, the language and formatting of these ideas is also more graphically driven with shorter sentences and paragraphs, extensive use of headings , call-out boxes, numbering, tabbing, etc. Graduate student texts I’ve seen rarely look anything like textbooks, but are just big gray boxes. In fact, graduate texts that make too much use of graphics might imply to the reader that the content is too “elementary” (S&H, for example, has lots of points that could be enhanced graphically, like the five practices discussed on 227-228 and the three research strands on 233-234, but the writers chose not to). While textbook publishers might see the use of graphic devices as a way to make information more accessible, does it also make the text seem more directive and authoritative (Look here! This is important! Don’t forget this!), and therefore less valuable to their level of cognitive learning? How does this reflect on writing handbooks like Faigley’s or Hacker? Or are they more of a reference that needs to have the ability of quick access?