In my first draft, I’ve got characters grimacing, smirking, scowling, smiling, and laughing. In every subsequent pass, I work hard to go deeper into the character’s POV to figure out what he’s actually experiencing. But it’s hard because that leads to a lot of teeth grinding, gut clenching, and hands curling into fists (not literally, but you know what I mean). And that’s not good, right? I’ve been told not to do that–but isn’t that showing what they’re feeling viscerally? It’s overdone, for sure, but…? So how do we show/express a character’s emotions without being clichéd or…dumb? How do you do it differently for men and women?
The best thing anybody ever told me about emotion in fiction was from Ron Carlson’s class: “Emotion lives in the body.” Words lie, physical reactions don’t. So your instinct to show emotion physically is the right one. The mistake a lot of people (not necessarily you) make is to forget that description is like salt, it’s there to wake up the taste buds, not overwhelm the rest of the dish. Since we’re talking about emotional description, I’ll go back to the key to description: Not Every Detail, Just the Significant.
So you have two angry people. One of them curls his hands into fists. If that detail is in there just to show generic anger, it’s not effective and it’s even distracting because most people do not curl their hands into fists during an argument. But if this is a specific abusive husband, and the scene is told from the wife’s POV, then those incipient fists are Significant Detail. The key is always “What significance does this action have in this story with this character?” The abusive husband with the fists is easy; what does it mean when his toddler son throws a temper tantrum with his hands balled into fists? What does it mean when his wife curls her hands into fists, too, for the first time? A guy in barroom brawl using his fists to fight isn’t significant; the same guy using the same fist to punch down bread because he’s learned that kneading bread is a way to defuse his anger is interesting. If the detail is generic and not specific to that character in a way that illuminates him or her, it doesn’t belong.
Your “gut-clenching” is a different problem. People don’t choose to clench their guts, their bodies do that for them instinctively. That is, even if you’re unconscious of the fact that you’re clenching your fists and grinding your teeth, once you recognize that you’re doing those things, you can stop. The knots in your stomach, however, are still gonna be knots because that was an involuntary response, like blushing, sweating, swallowing because your throat tightens, going cold from fear or warm from shame, or fainting from shock. There are hundreds of things our bodies do that are out of our control, and they all betray emotion in some way. Some people get stomach cramps when they’re very upset, some people get headaches, some people’s chests hurt, some people lose their breath, and all of those people only have those reactions when something of great emotional significance happens because they’re all reactions that the body produces in reaction to perceived threats. That means an ordinary argument, even one that makes the character really angry, isn’t going to produce an over-the-top reaction. The key, again, always, is significance. If you establish that this character represses her emotions and as a result gets stomach cramps and because of that eats Tums like candy, then that “gut-wrenching” become part of the story: an enemy can steal her Tums and leave her in agony; you can show her home alone after a bad event that’s she’s handled, curled up on her bed and crying from the stomach pain; she can hit with a blow that’s so devastating that she throws up in front of people. It that case, “gut-wrenching” is significant. I’m asthmatic, so when I did an asthmatic heroine, her shortness of breath reaction to shock was significant because if she didn’t get to her inhaler she was going to pass out from lack of oxygen. So the key to instinctive physical reactions is “How is this specific to this character and what impact does this reaction at this time have on the story?”
So significant detail, but jeez, you just want to show the emotion this character is feeling using physical cues, you can’t set up every character as an asthmatic with stomach ulcers. Okay, what’s the scene detail? Is your gut-wrenched character at an expensive dinner with important people? Then maybe instead of gut-wrenched, the character starts to feel seventy bucks worth of prime rib begin to rebel within. That carries with it the added threat of throwing up at dinner, which has the symbolic danger of throwing a gift back in the faces of people the characters needs, none of which is on the page but which is packaged in the “seventy-bucks worth of prime rib.” That’s all about money. But maybe it isn’t about money, maybe she’s having dinner with her perfect sister, and Sis drops the bomb during dessert, and the stomach-churning becomes the potential of decorating Sis’s Armani with a projective-vomited hot fudge sundae. Bottom line: ask yourself the significance of this detail for this character in this scene. If there is none, if it’s just generic, then it’s not specific and probably not useful.
So here’s my recommendation: Write the first draft as always with no restrictions. Put in all the gut-wrenching and teeth-clenching you want. Then in later drafts go back and look at what’s going on in that scene and what kind of physical reaction would be likely for that character. If she’s abrasive and confrontational, maybe she steps forward or leans forward. If she’s retiring and hates confrontation, maybe she crosses her arms over her stomach and leans back or steps back. If she’s cautious, maybe she goes very still, alert to danger. If she hates showing emotion, maybe she looks away because she knows she’s about to cry. If she feels overwhelmed, maybe she takes a step back toward the door. If she’s had it with whoever is arguing with her, maybe she picks up her phone to end the conversation or picks up a crowbar to end it a different way. If anger is making her turn warm and red-faced, maybe that makes her even angrier, that she’s betraying herself. If fear is making her cold, maybe she pulls her sweater tighter around her. In the rewrite, you know who the character is, so you can write the reaction she’d have, not the generic.
Short version: Emotion lives in the body, but it is specific to the body it lives in. What you’re going for is specific emotional cues that support characterization and move plot.