Gabe Duquette, writing at Liposuction, divides artistic fit into two categories: chords and maps.
Chords are elements combined in a way that is appealing, but not because the combination describes reality. Chords exploit the many evolved sweet spots of the senses. They can be comprised of “real” things but prioritize creation of an experience over transmission of knowledge. Chords can be consonant or dissonant — the sum of their parts can elicit pleasure or irritation, or even revulsion. Chocolate and peanut butter fit better than chocolate and ketchup.Maps describe what exists. They exploit the evolved need to understand how reality behaves. They can be aesthetically pleasing but they put the task of abstraction first. Maps “fit” when they achieve compression — when they eliminate redundancies in a pattern of real-world relationships without sacrificing essential features. Poor map fit is usually due to bad compression (irrelevant information that feels like fat on the bone) or outright misrepresentation (features that don’t appear in the abstracted territory). The Wire fits better than unedited surveillance camera footage or CSI: Miami.
There is a third category of fitness, however, which I believe Gabe has potentially overlooked because of his consumption preferences (film and music over visual art and literature). I'm tentatively calling the elements which belong to this category of fitness "Effect ideas," which is a significantly less catchy reference to the similarly functioning Speech Act.
Where chord elements are in the service of aesthetic interestingness, and map elements are in the service of insight/understanding, effect ideas engage in a bit of both. They are a third category of returns on artistic consumption. Effect ideas are mechanisms of action by a work and onto an audience member, the effect conveying in it valuable information, or posing valuable questions, about the world. Effect ideas are a form of philosophy which exert themselves through the reader watching himself watch the text. Through the self-watching, the reader comes to understand more about art, reality, perception, the world, or the self.
You realize you thought X thing about a novel character based on the character's gender, race, or other stereotypable feature. You realize you anticipated a different ending based on tropes of the genre. You realize something flawed about your literal perception. You realize you act or feel differently after exposure to specific media products, including behavioral/emotional mimesis of their protagonists.
You notice shifts in interior state when moving between color palettes. You notice you feel disgust at a character's actions, and that possibly it is the disgust of self-recognition. You notice your judgment or rage towards a fictional character is blown far out of proportion. You notice a work resonates more with you because you share physical characteristics with the represented subject — or that you have difficulty connecting to said subject for the opposite reason.
All these effect ideas, or rather effect ideas period, require some amount of reflection or "noticing" by consumers of the art stimulus. This is why visual arts and literary fiction especially encourage this category of response. Their consumption involves silent pondering, especially viewer self-evaluation when faced with the art object. (Though the effect idea plays an important role in all mediums.) Moreover, literary and gallery audiences are trained to treat these mediums this way, and in response the mediums are created for such a treatment. Often, the effect idea intercepts, and takes advantage of, these mediums's hermeneutic cycles of prediction, discovery (new information), and prediction evaluation (in light of new info). It is a feedback loop touched on by Peli Grietzer in Amerikkkkka:
Art is more 'artsy' the more [the reading] process bolsters its intended impact.
Effect idea fitness is a third category of fit, distinct from chord fit or map fit. It is a fitness between artistic or textual elements which cause reflection in the viewer so that a coherent theme emerges, or so that overlapping intellectual stimuli lead to a fruitful crossfertilizing of reflective responses. More over, it is a mobilization of mechanisms with an awareness of how they will be received in the viewer/reader, and of the kinds of reflective responses a viewer/reader will have if he subjects his response to the work to interrogation. Effect idea fitness is the so-called "artsiness" of the work, and a certain prerequisite for successful "high" art.