I think you need better questions instead of a direct answer and here were my 2 cents. Funny how people here think about A/B testing before they actually try to put an hypotesis behind the fact. As an average guy, I'd say that remembering things you've just listened to is very harder, except for people who have non-standard memory qualities. In ancient Greece, Epic saga started to be written to ensure the story wouldn't change through time. There's not only memorization involved, but also understanding and the ability to refer to someone else what you've learned. Have you ever tried as a child that game in which you have to pass a message through a number of mates by whispering it in their ear? It's disastrous and you don't even have to memorize it. Hammurabi has started writing laws for the same need of reference. And yet? In ancient times nothing was written, and people had to learn long codes and rhymes by heart and were requested to remember that for a lifetime. And it was easier: they exercised the skill a lot. Their attention span was linear, more focused, more trained. Did you actually learn logarithmic tables by heart? State capitals? We live in times that don't really promote retention in favour of linking concepts and knowing where to search the written information at speed, just because the lack of exercise has taken away our trust in our own memory. So I don't really think that the medium is important, it's the fit. Do you want a soothing voice telling you the beauty of an imaginary landscape? Or to give voice to a particular character from a book which matters to you? Or are you reading a technical reference book? Are you studying for repetition? Does voiced emphasis give you a stronger hook on sentences? Are you reading or listening to a book about public speaking? I remember prayers from my catholic days which I learned by heart in church without even reading them once - because I remember the rhythm and that kind of song they used to make you better memorize it. Still reminds me of Homer and ancient Greek times. What do you think?
