So, I was responding to this - specifically the common assertion that "books leave more to the imagination" - and the more I thought about it, the more ways that claim seemed totally bankrupt.
After a point, my response got long enough that I figured it makes more sense here, rather than slamming the discussion there with a wall of text. Without further ado:
Cinema as a medium does not require you to fill in any fewer "blanks" than books do.
Cinema probably has more blanks to fill in, by nature.
Let's start by pointing out how easy it is to effectively argue the exact opposite: Because literature is not constrained to audiovisual scenes, literature far more often "feeds" you things like a character's motivations, thoughts, desires, emotions, etc. by directly describing them - whereas films must rely on the audience inferring all that from very abstract clues. This isn't a big secret, but it never seems to come up in these discussions. Screenwriter John August has a succinct post on his blog about this that's worth anyone's read.
Honestly, you weren't even filling in those blanks.
Going a step further: The fact that a given piece of prose doesn't provide certain information, like the color of a shadow on a rainy pier, doesn't mean you're filling in that blank at all. There's no evidence to suggest that every time we read any prose our brain is immediately recreating an entire sensory experience down to deciding every single detail not provided. We don't even do that with actual lived sensory experiences.
We only "fill in blanks" as they are relevant, required, or suggested in the narrative - either directly or by mentioning something that happens to evoke a related remembered experience personally. Sure, you may readily describe details of an imagined scene when asked - but you'd be dishonest to say you came up with all of them before prompted to, when they weren't relevant to your experience/understanding of the narrative.
One corollary of the above, of course, is that cinema "filling in blanks for you" (assuming it did) doesn't necessarily preclude any level of engagement with any given film. In filmmaking, "the extra's socks" refers to a detail that is present but trivial; the audience is likely to ignore it unless they're specifically looking for it (at which point they're actively engaged anyway, filled blanks or not).
Actually, wouldn't providing more filled blanks be more engaging?
Why are we assuming that being given fewer pieces of descriptive information (again, if that were true) necessarily engages us more in creative/cognitive/interpretive processes? It's not like we're actively trying to synthesize brand new information that totally repurposes the text in a specific effort to be creative - we're filling in those blanks with familiar assumptions by reflex. If anything, leaving you to what you already know is likely to be less engaging. Often, the fewer the constraints the more cliche the response.
By contrast, if more detailed descriptive information is provided that you could not have anticipated, because it's totally new to you - say, a novel soundtrack on a film - you are now immediately determining the relationship between that and the rest of the experience. You are making decisions and evaluations that you would not have made when given less information.
The reductio ad absurdum of the "less is more" line is that a blank canvas is the most intellectually stimulating and engaging possible painting. We correctly say that's ridiculous because without at least some inciting pieces of information we don't have anything to interpret, build upon, and synthesize from. If we accept that, how can we simultaneously argue that any medium would be less engaging by providing more inciting information that has to be interpreted?
We take non-diegetic soundtrack (i.e. music that is not coming from the "world" in the film, like the Jaws theme playing while the woman is swimming in the water) for granted, but reflect on that for a moment: It's information that's meant to augment the scene depicted in the film only on the level of abstract connections - the fact that different soundtracks overlaid with the same scene can make you relaxed or tense is a testament to those "filled blanks" actually engaging you more.
You know what - why don't you choose what blanks to fill?
It seems easy to assume that the cinematic frame is dictating your focus - hence the usual "movies do all the work for you" arguments. But I think it's the opposite, most of the time. I made the point earlier that when processing experienced sensory information we only pay attention to certain areas of focus; we're not taking in the whole scene all the time as equally important. Why would that not be the same for films?
Unless there literally is nothing on the screen but a word, or a detail-less image, you have free reign to direct your attention to and focus on whatever you want, from the extra's socks to the signs of the shopkeeps in the background of a busy city shot. Even extreme close-ups still allow you to go over the details of the thing you're looking at, the imperfections in an actor's skin, the striations in their iris, etc.
The cinematographer's efforts, of course, often strongly suggest where your attention should go - but it's not like they have you strapped down with a speculum on each eye and a neck brace holding your head still like in Clockwork Orange. And even that's more style than medium: Plenty of films feature less tightly-focused centers of attention and invite the audience to wander.
By contrast, however, with literature there is actually no escape from what the author describes to you. There is no screen to wander in. They may give you details to elicit some gap-filling on your part to paint the parts of the picture that they don't, but I can't see why the exact same thing wouldn't happen for audiences regarding off-screen action. The difference is that within what the work does provide, you have a freedom of attention that literature is incapable of providing by nature. A single frame of a film can include enough detail of an urban street that would take several chapters of a book to even articulate in the same level of detail - and in an instant we take it in our attention drives our focuses around the image.
I don't really have a well-structured conclusion; sorry - this was a rant, not an essay.
When I hear people complaining that movies are spoonfeeding them info, they're almost always complaining about a given execution, not anything that is intrinsic to the medium. And I wonder how many people who claim to prefer the cognitive engagement of "filling in the blanks" that books provide but movies lack were also applauding, say, Heath Ledger's subtle but compelling performance in Brokeback Mountain, Amelie's use of color and lighting, etc.
But don't let me hog the soapbox.
I'd love to hear any more thoughts/responses to this.