How can text "show" us anything?

One of my pet-preoccupations is the debate within the horror community whether a monster is scarier if it's shown or merely suggested.

It's clear enough what this distinction amounts to in visual media like film and comics. Showing means the explicit depiction, on-screen or in-panel, of a relatively complete image of the monster. Suggesting means offering just enough hints of what a monster looks like--partial or unclear glimpses, sound effects, claw-marks or carnage or other traces of activity--for audiences to form their own mental images of the monster.

Does this distinction have any application when it comes to prose fiction like novels or short stories? Does it even makes sense in that context? Prose is not a visual medium, and therefore can't literally show us anything, the way movies or comics can. With unillustrated text, there are no external images; the only images are the mental ones readers imagine. In this literal sense, words can only ever suggest an image. But is there any sense in which they can also be said to show it?

I think so. Here's one way to think about imagination, art, and language that supports the use of this distinction where prose fiction is concerned:

We have evolved impressive visual and memory systems to take in and store information from the world around us. Impressive as these systems are, they aren't magic. There are no limits to the information available out there, but our visual systems have limited bandwidth and our memory systems have limited capacity. Our visual systems have grown uncannily efficient at recognizing and extracting only the most essential information and converting that into the rich experience of a visual field we enjoy. Our memory systems have grown just as efficient at further extracting only the very, very most essential information, breaking it down into components, and storing those units in the form of "dispositional representations" that allow us to reconstruct rough, incomplete, but usually good enough mental images of things we've previously perceived. What happens when we remember something visual is, the information stored in these dispositional representations gets sent "downstream" to the visual cortex--the same one that processes visual perception--and from that information, it generates the experience of a mental image (see this post for a much more detailed discussion of all this).

Of course, even very vivid memories are much fainter than perception. That's why people carry around photographs of loved ones. No matter how well they remember the loved one's face, there's no substitute for being able to actually look at it. The reasons for this discrepancy should be obvious: the visual cortex receives vastly more and better input from perception than it does from memory. Visual perception is supported by all kinds of dedicated anatomy (binocular arrangement of the eyes for depth perception, cone photoreceptors for color perception, etc.) and early-visual pathways and processing systems (for functions like edge-detection, various Gestalt effects, etc.) that have been fine-tuned by long evolution to make best use of as much of the highest quality information as possible, and what's more, they can continuously extract further information from whatever is being looked at. Memory has a finite store of information to offer, and that information has undergone processes of selection, refinement, and specialized coding which leave it more abstract, attenuated, and even degraded, compared to what perception takes in; what's more, when this information serves as input for mental imagery, it doesn't benefit from the early-visual structures or systems downstream of the visual cortex--those channels are all tuned to the outside world, and play no role in introspection.

Now, when we form mental images in imagination, we don't generate them by magic. The visual cortex does that work, too, and it needs input from somewhere. Where it gets that input from is memory. Once we've stored information in dispositional representations, we can reactivate it in patterns previously perceived, but we don't necessarily have to. We can also activate it in new patterns to generate new mental images. That's a wonderful ability! The problem is, these new imagined images are as faint and sketchy as remembered images, because they're formed from the same low quality and quantity of input.

One important function of visual art is to help make up for these limits of imagination. Visual art can serve as an extension, or prosthetic, of visual imagination, by putting a mental image out where we can see it. By committing a mental image to paper, canvas, clay, or whatever, an artist is first and foremost making it available to perception. Even if the artist only sketches a rough equivalent of the mental image, that still improves his access to it, because now it exists in a stable form that can be inspected with the full cognitive power and sensitivity of the visual system, rather than as a fleeting internal image that must be maintained through concentration. An image realized in art can also be added to and improved upon, in ways that would exceed our mental capacities if we tried to do them in imagination without the art as an external aid. That's why sketching is such an important part of the artistic process. In Natural-Born Cyborgs, Andy Clark (to whom I owe this idea of art-as-prosthetic) asks, "Why not simply imagine the final artwork 'in the mind's eye' and then execute it directly on the canvas? The answer," he goes on to explain, "is that human thought is constrained, in mental imagery, in some very specific ways in which it is not constrained during online perception." He then describes "a kind of looping process" in which "the artist first sketches and then perceptually, not merely imaginatively, re-encounters visual forms, which she can then inspect, tweak, and re-sketch so as to create a final product."

That brings us, at last, to the question of prose fiction. Language, it turns out, can also serve as a prosthetic aid to visual imagination. Whereas visual art can make a mental image accessible to perception, our ability to to select and combine words to convey precise details tremendously enhances the quality and quantity of information that can be retrieved from memory for the generation of mental imagery. It greatly increases our control over not only the content of a mental image, but also formal features like perspective, framing, figure-ground relations, "scene cuts" and transitions, etc. All that early-visual stuff that imagination can't access on its own?--the right description can direct us to visualize something in a way that simulates those effects. Formulating a mental image as a description also makes it more stable, which permits us to devote fewer resources to maintaining it and more to experiencing it. The ability to revise, substitute words, tinker with phrases, etc. lets writers employ the powerful internal/external looping process that artists employ in sketching, to add to and improve upon a mental image in a way that wouldn't be possible if the imagery weren't directed by the choice and arrangement of particular words. Used in this way, language makes our mental images virtually external enough to confer some degree of all these advantages of a literally external canvas or screen.

Admittedly, all of that still leaves us a far cry from perception. Prose fiction just can't compete with visual art in that regard. That isn't what it does best. Nevertheless, language serves this prosthetic function effectively enough that it makes sense to distinguish between times when it does so and times when it doesn't, and to call the former "showing" and the latter "suggesting."