Just came across some research which says that “the human brain processes and retains more information if it is digest in either its verbal or written form, but not both at the same time.” (Research points the finger at PowerPoint by Anna Patty, The Sydney Morning Herald)
The UNSW (Australia) research shows that the brain’s short-term memory is limited and that the “cognitive load” becomes too heavy, basically, when information is presented in both its visual (or written) and its verbal (or oral) form at the same time. The professor (John Sweller) who developed this “cognitive load theory” says flatly that PowerPoint presentations have been disasters and they “should be ditched.”
The article even mention something I do all the time: not content to simply listen to scripture being read aloud by a human voice (in church), I feel compelled to read along in print (the same translation and sometimes a very different translation — which brings up other questions of cognitive function: how much are you getting when you’re getting the same thought not just in two formats (print and oral), but also in two different versions?).
One other thing: Professor Sweller also says that it’s better to teach by presenting an already-solved problem rather than asking students to work out the problems themselves. That seems counter-intuitive. But he says that “Looking at an already solved problem reduces the working memory load and allows you to learn. It means the next time you come across a problem like that, you have a better chance at solving it.”
Interesting. So students learn it better because more of it gets into their “working memory.”