Being in the multimedia biz, I’ve often heard (and even cited) bromides like “we remember 10% of what we read, 20% of what we hear, 30% of what we see, 50% of what we see and hear.” This is totally bogus, according to this guy.
The so-called “Weiss-McGrath retention study” is referred to in one of our clients’ marketing communication materials, looking quite authoritative. It appears in a 1963 book by Harold Weiss and J.B. McGrath, Jr., Technically Speaking, Oral Communication for Engineers, Scientists, and Technical Personnel. Not readily available, I think, judging by this Amazon link. Seems like something that would have been the subject of more recent (and possibly more authoritative) studies, but I haven’t run across any. I did run across some possibly interesting citations in a discussion of forensic animation — something I’d never heard of.