Documentaries are the most persuasive form of entertainment.
The written word depends on content & the spoken word depends on the emotional appeal of the speaker... paintings are purely aesthetic and deal with abstract truths... plays require lots of time, energy, and immersion to experience their full effect... but movies are immediately accessible and use MOTION PICTURES & SOUND to communicate.
TO GET A DIRECT LINE TO THE SUBCONSCIOUS BRAIN
MIX MOTION PICTURES & SOUND.
The impact of a message is greater if it is less abstract and more visual.
If an agenda is visualized and made immediately visceral using "true" footage, your point of view could be engineered to feel self-evident.
It's obvious why we need to invade Iran.
It's obvious why we need to donate to this charity.
Look. At. This. Footage.
The other component, actually, is the mixture of synchronized sound.
If the footage were completely silent, it would not be as effective (see: silent films).
Synchronized sound reinforces the reality of the images (even if they're not real).
Sound being one of our most primal senses, when mixed with motion pictures, creates a phantasmatic cocktail narcotizing the brain in submission to the movie.
It's alchemy with cinema.
Since documentaries are a highly visual medium - and because the nature of watching a movie is similar to you re-experiencing an actual lived event (meaning, movies are very similar to implanted memories) - whatever the camera points to, the audience will accept.
Even if someone in the audience disagrees fundamentally with whatever the documentary is about, the idea still has a higher chance to stick as compared with every other type of media.
That's because the idea will slip into the subconscious mind of the unbeliever as a fact before the rational mind has time to debunk it.
And that fact will interact with the mind for a longer duration than if introduced via other media (brochures / music / sculpture / etc).
Debunking in a documentary occurs only after the fact, if at all.
Documentaries are also highly effective because their agenda will be reinforced in the minds of those who already agree: and it's only a matter of time before this network of belief surrounding the unbeliever is accepted as a truth, even if begrudgingly.
Take for example Dinesh D'Souza's film "2016: Obama's America."
I saw this movie in a multiplex simply out of the novelty of watching a documentary in a multiplex. It happens so rarely.
I also have a particular love for the obscure & bizarre.
Anyway, so I went with a Moleskine in hand (the girl at the ticket counter said, "You're actually going to take notes during the movie?" LOL Yup!) and checked out the movie.
Basically, I don't agree with the subject matter.
I didn't agree walking into the movie, and I didn't agree leaving the movie.
But, in many respects, the movie wasn't for me.
The market was for the more Christian-Republican minded among us.
And that's fine.
Everybody deserves media
(may the best media win).
Regardless, I saw the movie.
Regardless, I walked away with the images in my head.
Regardless, my mind entertained the possibility of some of the events portrayed (paving new pathways in my brain).
Emotional connections were anchored for characters I normally wouldn't empathize with.
And the things I did not agree with seemed, at least on some level, understandable.
And I'm an unbeliever.
Imagine the effect a documentary has on a believer.
If someone had simply told me the arguments presented in the film, or if I had stumbled on a blog post about the exact same subject, the effect certainly would not have been the same - and would've probably pushed me further away from their point of view.