
What you see is what you learn.
Isn't this true?
Maybe.
There's no complicated research to back this statement. But there is a parallel: WYSIWYG.
In the early 1980s, computers had a TEXT-BASED INTERFACE, meaning you had to understand (and make the computer understand) everything in TEXT (most popular such product being Microsoft DOS). Needless to say, this was not a permanent long term solution to understanding computers and soon enough, bright engineers started looking for an alternative developed the GUI or the GRAPHICAL USER INTERFACE. They called this new interface the WYSIWYG or What You See Is What You Get; no complicated text to be memorised. Maybe this single shift from TEXT to VISUAL has changed our world by making computers accessible to so many more people around the world.
Will textbooks ever shift from being "text" books to "visual" books? In a way, with eVideo being a companion to Sinhals "text" NOTES, it has already started to happen.
Perhaps eVideo's myDigitalBook is the world's only book which displays animations and visuals.

Most people do learn better and faster if they can visually see something. Until now, we were in the text-based system because of various limitations. But with better technology and resources, its obvious that in the future learning will be more visual and less textual. WYSIWYL: What You See Is What You Learn, a boon for all the Visual Learners in the world.
We see. We learn.
Its that simple.