2. Ascent. There is something like a natural progression, a sort of development, in the way we attend to fictional works, such as novels, movies, or theatre plays. First, you simply follow the flow, and yield to impressions: this is the stage of immersion. Then follows an activity of comparison: noting characteristics, finding differences and commonalities with other works, understanding patterns and developments. Finally, with the recognition that there is a shaping mind (or several minds) behind all this, someone who has intentionally created it so, there is a stage of appreciation. It's the artist's imaginative performance that comes into focus at this last stage.
Let's take an example: you're reading a novel. The first stage is immersion. You get 'into' the story; you start orienting yourself in this fictional world, you get to know the characters, sometimes from within their own head, sometimes only from without; as the story develops, you're curious why they act as they do; you want to know what happens next. (It's just the same when watching a movie: you're attending closely to what is happening on the screen, you're with the plot, apprehending the events that unfold, listen to the characters' words, watch their actions, empathize with the feelings they express in their body language and tone of voice.)
At this stage, you are not aware of your own position as an observer; you're absorbed — you don't reflect. You're 'dreaming the fictional dream', as writing coach John Gardner has put it.
There may come a point, however, when you step out of this immediate engagement and enter stage two: comparison. This might happen while you're still reading, or perhaps afterwards; it may happen only after you've read many books; and perhaps even then only after prompting from a teacher or a review in a newspaper. Whatever triggers it, you attention is drawn away from what is happening to the characters to what you can observe about this piece of fiction as such. You begin to notice differences and commonalities with other stories; you start categorizing, possibly assign them to genres; you may identify stylistic elements, perceive patterns, developments, and so on.
Once you put a fiction into a comparison class, it speaks to you in a different way. You can't be exclusively absorbed in that single piece any more, because you are now aware of its relationship with many others. It does no longer only exist in the events and emotions it presents to you; it is now also bound into a larger context of ways of presenting such events and emotions. The space of what you're perceiving has widened considerably: from merely something that's going on (for you to raptly enjoy) to goings-on that merely present one lone path through a vast network of connections.
Noting this, of course, you may well ask yourself the question why you are on this particular path now, and not another one. There may be reasons behind it or not, but you'll find that now you realize a shaping will behind the fact that you are going in that particular direction right now. Someone (the author, or artist) has taken choices, has deliberately arranged things in this specific way. And once you're aware that many of those decisions come from a unique, creative mind, the mind of someone who knows about those options, and who has a sense of direction that somehow got transferred upon these fictions — once you notice that, you're on the level of appreciation.
3. I have started above with the claim that there is this development, or aesthetic ascent, in our responses to fictional works. We must get clearer about the status of that ascent.
First, of course we don't go through these stages with every single experience we have of a fictional work. In other words, you might have got to the level of appreciation when watching a movie yesterday, but that doesn't mean that you can't watch another movie today and remain on the level of immersion. (It's not quite so clear that you can watch the same movie today and remain on the level of immersion. I suspect that once you've reached some level of reflection with respect to a particular instance of fiction, it's difficult, perhaps impossible, to again retreat from that level. Compare this to knowing a foreign language: if you can't understand French, say, and you're sitting in a café in Paris, you may perceive all the talking around you, which you can't interpret, as a kind of music, an acoustic background, sounds without any direct meaning to you. Once you've learned the language, however, it is nearly impossible to perceive those same sounds that way. You'll hear the meaning of what is said, whether you want it or not. I think it's similar with perceiving an instance of fiction on the level of comparison or appreciation: once you're there, you can't go back.)
Second, this ascent is not tied to stages of our personal development. It's not that we're merely immersed in all novels, movies etc. for the first twenty years or so of our lives, and then learn something, get up to the next level, and from that point always remain there. Sure enough, with education and personal maturity comes also a greater ability and affinity for reflection and appreciation in these matters. But there is no reason why young people couldn't go through all stages very early in their development. (Even young children start sorting stories they know by how much they like them, and later on they may find they have a favorite author or two whose works they like most.)
Third, at all three levels external elements have an influence on what we experience, in addition to the aesthetic ascent. You may be immersed in a story at first, but your thoughts may drift away after a while. (So you're not reflecting on what goes on in the story, but you're suddenly in the mood to think about your plans for tomorrow, perhaps triggered by a sentence you've read.) Likewise, your concentration may fade because of physical or mental fatigue; or your ability to follow an emotionally disturbing story or film may be exhausted after a while. (You simply can't take any more of those depressing pictures or situations.)
On the level of comparison, personal preferences may guide your perception. For example, if you've just taken up dancing classes or some sport, you might be sensitive to aspects of physical activity or competitiveness and experience a movie which reflects on them much more intensely; this might lead to a preference for that category which is merely rooted in your own current situation. (Note that in this case, there is still much going on on the comparison level between movies within that same category. The preference is for focusing on movies which deal with that particular aspect, but you're still going to compare them with each other for how they do that; and that comparison activity is of course the more interesting one.) Similarly, there are many other influences here from our own personal constellation: we may find certain actors more attractive than others because of their physical appearance, their unique voice, or their intriguing screen persona; we may be fascinated by the novelty and relative strangeness of something we've only just started discovering; or we may even relish a slight quality of indistinctness in styles we're not yet used to. (Try reading Shakespeare in original Old English, or generally something written in a language you can understand reasonably well, but you're not yet quite familiar with. The fact that there are nuances you won't get, and the fact that you know it, will add a special, unique charm to those works; but it will inevitably wear off after some more practice.)
Finally, on the level of appreciation, where we focus on artistic performance, there is another set of external elements that may influence us, such as a personal like or dislike for the artist, or an own personal experience practicing the art in question: you can recognize an achievement much better if you know from first-hand experience what it takes to get there, what labors, patience, and perseverance are required for it. Thus, on all three levels there are external factors interacting with the development we're looking at here, aesthetic ascent.
(I don't think there is a need to 'purify' our reception of fictional works, in a way that minimizes or even eliminates those external influences. It's just important to be aware that aesthetic ascent, in the sense described here, is not the only thing going on in those experiences.)
There's a fourth aspect to aesthetic ascent. Our experience of an instance of art is deepened, its richness and intensity increased on each of those levels (contrary to widespread opinion that a perception that is unspoiled by theory is the most intense). This connects back to my earlier post about appreciation of the craft. I said there that conceptual skills are required, and must be developed, in order to get to a more refined appreciation of art. Aesthetic ascent is a crucial factor in building these conceptual skills. Understanding is enhanced by informed ways of looking at things; and the ability to appreciate fictional works is no exception to that rule.
 John Gardner, The Art of Fiction. Notes on craft for young writers. New York: Random House 1984.