“Beat” is actually an acting term. In a movie or play, it describes a brief interruption or pause in the action or dialog. The result of putting a beat in can change the emphasis on a line of dialog or the meaning of an action, and do it extremely economically. The detective’s moment of stillness before she slowly reaches for the matchbox tells us that she’s realized something important; the brief pause between two lines of dialog gives the characters – and the audience – time to react.
The terminology has bled over from acting and visual media into prose writing, but it means the same thing. The difference comes in how a writer indicates the pause. An actor hesitates; a writer has to actually say “he hesitated.” A director has the camera cut away from the fight for just a second to show the horrified look on a bystander’s face; the exact same interruption for a writer runs into all sorts of viewpoint and pacing considerations (Would the first-person narrator actually notice a bystander’s reaction when he’s dodging punches? Would it distract him if he did? Is it too flat and generic to say “The bystander looked on in horror”? Is it going to be too much of an interruption to give a couple of sentences or paragraphs of description of the bystander?)
On the other hand, writers have a couple of useful tools that actors don’t. Punctuation, for instance. Standard punctuation is meant to indicate differences in tone and timing; there’s a reason that the period is also called a “full stop.” Commas are shorter pauses – just enough for a breath – while semi-colons and colons indicate longer breaks, dashes more of an interruption, and ellipses a hesitation or fading out.
Punctuation gets even more useful for indicating beats when writers use it in non-standard ways. This has to be done with a light hand, or it looks as if the writer is simply ignorant of standard punctuation rather than doing it on purpose. Still, the ability to write “‘Put. It. Down.’ He scowled – she lifted it higher – a flurry of motion; a crash; a fading cry…then silence, and curtains blowing through the broken fourth-story window.” makes it all but impossible for a fiction writer to stick strictly to correctly punctuated sentences. It’s hard to pull off effectively, though, if one doesn’t know the standard rules and usages to begin with. For those who are doubtful, or who want an engaging refresher course, I recommend Karen Elizabeth Gordon’s The New Well-Tempered Sentence.
Sentence fragments and short paragraphs can also provide beats, especially when they are a) not overused and b) in sharp contrast to whatever is around them. That is, a sentence fragment in the middle of an action paragraph composed of relatively short sentences will provide a less strong beat than one that occurs in the middle of a long description. Compare:
He dodged left. The bear dodged right. He ran for the tree. The branch was just out of reach. He jumped. Missed. And the bear was on him.
A row of ornate picture frames lined the back of the mantelpiece. Most of the pictures were of a single person in dark, old-fashioned clothes, but two were of couples, and one showed a family grouping of three adults and five children. A white candle-stub stood in front of each picture, trailing cold wax and bits of blackened wick across the gray stone. Except for one. At the far end, half-hidden behind the portrait of a stern-faced matron in black, stood the picture of a ten-year-old boy in a baseball uniform, glaring at the unseen photographer…and at the empty space in front of the picture where his candle should have been.
In dialog, the speech tag can act as a beat, especially if it is longer than “he said” and/or comes at the beginning or in the middle of a line. “You insist that I say it? All right, then,” he said doesn’t have a beat in it (this is what people really mean when they claim that “said” is invisible as a speech tag). But “You insist that I say it?” he said. “All right. then.” has a very short beat in the middle, because the dialog is interrupted just a little, even if it’s only by “he said.” And “You insist that I say it?” He looked down. “All right, then.” has a longer beat, because the reader has to switch from dialog to the character’s actions and back.
Beats in dialog can come at the beginning or the end of a line, too, to indicate the pacing and the rhythm of the conversation. There are a couple of things to watch out for here: one is to not get carried away and put a beat somewhere in each and every line. Another is to vary your placement. Even if it’s the sort of conversation where there’s a dramatic pause between several lines in a row, you can make it look varied by putting the first beat at the end of the first line and the second beat at the beginning of the third line: “I’m coming with you,” she said firmly, and waited.//”You’re not going to give up on this, are you?”//She smiled. “Do I ever?” reads more smoothly, in most cases, than “I’m coming with you,” she said firmly.//”You’re not giving up on this, are you?” He sighed and shook his head.//”Do I ever?” she said with a smile.