I recently came across a very interesting blog post by Will Thalhelmer which I highly recommend. It traces the origins of the famous "what people remember" model — 10% of what they read, 20% of what they see, 30% of what they hear, etc. I will leave you to read the details of where all this came from and how it is completely unfounded in any research whatsoever. Apparently this groundless model backed by absolutely nothing may derive from Edgar Dale's 1946 Cone of Experience, an "intuitive model of the concreteness of various audio-visual media" as Thalhelmer puts it (see below). No percentages, which were apparently first published by D. G. Treichler, an employee of Mobile Oil, according to Thalhelmer's and other's research.
But what I found interesting here is how this cone of experience has had a long and active life span over a total of sixty years, versions of all sorts continually cropping up. A great example of how powerful a visual model can be even with no basis whatsoever in fact. A warning to us all to be more wary of how the visual can sometimes be deceptive, as Plato would say.