Action beats are phrases or sentences that accompany dialogue that describe the speaker’s movement or facial expressions. Like dialogue tags, they may precede, be interspersed with, or follow dialogue.
In a similar fashion, phrases that communicate what the speaker is feeling are called emotion beats. Action beats and emotion beats are so similar, many experts group them both under the heading of action beats.
Examples of action beats:
John smashed his fist on the table. “I never said that.”
“I’m sorry.” She looked away. “But you asked.”
“Sure. No problem.” Amber closed her eyes and bit her lip.
See our article How to Write Engaging Dialogue for tips on how to use action beats to bring your dialogue to life.