I've talked in the past about the problems things like alternate endings can pose to the integrity of a story, and the same is generally true of interactivity in its broadest sense. There are precious few examples of stories that offer the reader a choice in what happens next, and then go on to reward them with a collection of equally enjoyable and satisfying conclusions afterwards. My perspective on the matter still hasn't changed: I firmly believe that a linear story will almost always be superior to one with multiple branches or endings.
However, that isn't to say that I dislike the idea of interactivity in storytelling. Far from it!
Something that I've been meaning to talk about for a long while now is the degree to which books and the textual medium have always been just as, if not more, interactive than any other form of storytelling out there.
There is a specific dimension to textual storytelling that is left almost entirely in the hands of the reader. Namely; the visuals. Theatre, film, video games, and art are all predominantly visual mediums, and very little is left to the audience's imagination when they're sitting in a theatre or watching a screen. Books do, of course, rely on description to fill in these visual blanks, but this generally varies from author to author (I'm a big fan of staying light on the description myself), and even the most vivid of sentences are never going to create exactly the same image in the reader's head as they do in that of the author.
In fact, when you think about it, the auditory element of novels is also entirely in the hands of the reader. We're all going to give the voices of characters different accents, inflections, and cadences in our heads. Even in the most meticulously described stories, there will always be a wealth of features that we have to fill in for ourselves. Every reader has, at some point, conjured up the outfit a character is wearing in their head, the layout of a room, or the features of a face. These are things that stick with you for the entire novel, and they define a huge part of how we respond to the material in hand.
If you compare it to a move, the job a reader has isn't much different to that of the casting director, set designer, and costume designer all rolled into one. We have the blueprint of the story laid out to us with instructions on how each of these elements should generally look or feel, but the details are all ultimately up to us. We conjure up entire worlds in our heads as readers, and there are millions upon millions of different interpretations of Hogwarts, Middle Earth, and Watership Down out there across the world. Christian Grey has a thousand different faces, and Ned Stark has said "Winter is Coming" in too many different ways to count (though most of them probably sound like Sean Bean).
I'm sure I've mentioned it before, but this is part of what makes books so special to me. They hold the potential for far more interactivity than the majority of other mediums out there. Even in a non-linear video game with dozens of choices that all alter the plot in some way, does that degree of interactivity really compare to creating entire worlds, characters, and voices in your own head?
I'd love to hear what other people think about the subject. Do you agree that books are as interactive as I seem to think? Or am I overlooking the degrees of interactivity present in other mediums?