Please know that I am not an expert! Check out Jeff Curto's podcasts about Gestalt for a photographer's take on this.
Closure is our brains’ tendency to supply missing pieces – we recognize a human face, for example, even if the eyes are covered. The viewer completes the puzzle and in fact gets satisfaction from doing so.
In writing, this means that we don’t have to supply every detail of a person’s appearance or actions – we include just enough so the reader can create an image that will let her understand the story. For example, check out the opening of Susan Fox’s March 30, 2010 release, Love, Unexpectedly:
“What’s new with me? Only everything!” Nav Bharani’s neighbor Kat widened her chestnut brown eyes theatrically. She dropped her laundry basket in front of one of the half dozen washing machines in the basement laundry room of their apartment building, then hopped up on a dryer, clearly prioritizing gossip over chores.
The name Nav suggests the actor Naveen Andrews, so right away I assume that Nav is dark haired and handsome. Kat’s comment and her hopping up on a dryer suggests she’s young, agile, and lively. The author didn’t have to tell me those things in so many words; my brain filled in the blanks from the information she did provide.
Once something has directed our attention in a particular direction (a path or lines of perspective, for instance), continuance is our tendency to continue to look that way until we see something interesting. In Western society we read from left to right, so we’re more comfortable when the path draws us from left to right.
Structure does this in a tale. We place the most important element, the most powerful word or image, at the end of the sentence, paragraph and story. We seduce the reader into following us along the trail, tossing out crumbs as we go and all the while making them wait for the cake.
It can be as straightforward as this line from Love, Unexpectedly:
Even in the crappy artificial light, with her reddish-brown curls a bed-head mess and pillow marks on one cheek, Kat was so damned pretty she made his heart ache.
The beginning of the sentence sets up the reader’s expectation with the word even. We read on to find out even what? Next, the physical description lets us picture the setting and continues with the set-up: even though she looks a mess…what? Only when all that work is done does Fox deliver the powerful "she made his heart ache."
That’s satisfying – and enticing.
Our brains like to group things, and similarity of size, shape, and colour or value (lightness or darkness) are three visual categories the brain uses.
In storytelling, this works in the sense of style or voice. The terse sentences of a 1940s noir mystery novel create a mood for the reader; using them in a romantic comedy would contradict the light, generally happy tone of the story and the dissonance might rankle in the reader’s mind.
Parallel sentence structure and agreement are two obvious grammatical uses of similarity. If it aren’t there, readers are jolted out of the story as his brain tries to make sense of the awkwardnesses.
In the opening of Firefighter Daddy (July 2010), Lee McKenzie uses two different kinds of similarity.
Mitch Donovan hadn't been inside this second-grade classroom since…well, second grade. He noticed two things right away—the chairs were a lot smaller than he
remembered, and the teacher was much younger.
The first sentence uses repetition of words to create humour; it sets the tone for the book. The second applies structural repetition for rhythm; that makes the sentence flow smoothly.
Visually, proximity is often a more powerful way to group things.
Close edge creates visual tension; the closer items seem to be to each other, the more likely we are to think they belong together.
Images in which items are or appear to be touching can be stronger than close edge
overlapping items really look like they belong together.
However, in writing, close edge is a stronger technique than overlapping. We want to create tension in the reader and crank it tighter during the course of a story. That means the detective can’t match the criminal with the crime too quickly, the romantic hero and heroine can’t touch (or overlap) too soon. By letting the characters get close and then pulling them apart before they get what they really want, writers force readers to keep turning pages in an attempt to relieve that tension.
Sharon Ashwood’s Unchained (July 6, 2010) creates suspense by making the reader wait for each revelation.
Ashe stilled, straining to pick up the slightest whiff of Nasty Critter. A light breeze chilled the sweat along her hairline. Her heart hammered hard, but her thoughts were clinically calm. If you were going to kick the ass of anything bigger than a garden sprite, discipline was key.
We know the protagonist is hunting a bad guy, and Ashwood leads us through the chase move by move, letting us see just one enticing element of the story at a time. We get close…
Ashe dropped back to the counter just as the outside door swung open and someone walked in. In a flash, she aimed her gun in a two-handed grip.
Then she froze. Oh. My. Goddess. But she let her surprise last only a microsecond. Her eyes on the newcomer, she hopped to the floor. “What are you doing here?”
Captain Reynard gave a slight bow. “I am looking for you.” His so-English accent sounded like something off Masterpiece Theater, but that baritone voice was pure seduction.
…but he’s not the bad guy, so the hunt is still on. However, now there’s a new kind of tension in the story as well and while Ashe and Captain Reynard get closer during the course of the book, something keeps them apart: close edge but no touching, in the storytelling sense.
No matter what the genre, a tale always lies in how the characters travel their paths, and the readers' pleasure comes from being led along with them, one tasty crumb at a time, until we reach the resolution, the big picture…the cake.