This will be a new series on my blog, coming out on Fridays. (I may not post one every single week, but they'll always come out on a Friday.) My goal is to impart some wisdom from my discipline - psychology - to help writers, in part because I see a lot of tropes over and over that are not really in line with what we know about human behavior. (And I have so many writer friends with their own expertise - I'd love to see others share some domain knowledge like this to help us write more accurately!)
One of the big tropes I see is how people respond to extreme fear, usually by soiling themselves in some way. George R.R. Martin just loves to have his characters pee and crap themselves, but he's certainly not the only offender. In fact, I just finished Sleeping Beauties by Stephen King (one of my favorite authors) and Owen King, and was really frustrated when once again, the peeing-oneself-in-fear trope reared its ugly head.
Do people pee themselves in fear? Yes they do. It probably doesn't happen anywhere near as often as it does in books, but then we don't usually encounter some of literature's most fear-inducing creatures in real life. So we'll say for the moment that the frequency with which people pee themselves is fine. In fact, that's not even the issue I have.
The issue I have is when this response occurs. In the books (and movies & TV series too), something scary shows up and the character immediately wets him or herself. Nope. That's not when it happens. It would happen after the fear moment has passed - after the creature has been beaten or moved onto another target, just as the character is beginning to breath a sigh of relief. That's right - you pee after you've been afraid, not during.
How could that be? Let me talk to you for a moment about the fight vs. flight response, for which I've created this visual aid:
sympathetic nervous system is getting you ready to expend energy, because fighting or flighting, you're going to be expending energy. Your body releases chemicals, like epinephrine (adrenaline), norepinephrine, and cortisol. Your heart rate and blood pressure increase. Your pupils dilate. Your muscles get ready for action.
But as these systems are charging up, other systems are slowing or shutting down completely. Your immune response is suppressed. Sexual arousal is suppressed. Digestion slows or may even stop. And your body stops producing waste materials, like urine. It's not very helpful if, just as you're getting ready to fight for your life, you realize you're hungry or need to pee, or if your allergies act up and you've suddenly got itchy eyes, sneezes, and a runny nose. Those feelings go away, temporarily, so you can focus your energy on the surviving.
But after the stressful period ends, your parasympathetic nervous system takes over. Unlike the sympathetic nervous system's "fight or flight" response, the parasympathetic nervous system's response is "rest and digest." (I've also heard "feed and breed," because of the aforementioned impact on sexual arousal.) Those processes that were slowed or stopped start up again. Your muscles relax. You can imagine where this is going.
The best portrayal of this concept I've ever seen was in The Green Mile: the scene where Wild Bill, one of the inmates on death row, grabs Percy, one of the guards, and threatens him. The other guards get Wild Bill to release Percy, who rushes to the other side of the corridor and collapses on the floor. Wild Bill says with a smirk that he wouldn't have hurt Percy. And that's when Del, a fellow inmate, points out that Percy has just wet himself.
Percy is away from Wild Bill and safe. While the emotions he was experiencing when Wild Bill grabs him are still present (he's still upset), his body is returning to its previous physiological state. And that's when his bladder lets go.
So there you have it - if you really want your character to wet him- or herself, it should happen after the character begins "coming down."
I know one question I've gotten when discussing this in the past is, why do animals pee on someone/something in fear? Remember, animals don't have the same highly evolved nervous system that we have. Their systems are not going to shut down in the same way a human's does. Also, their reaction is not directly to fear, but is (arguably) an evolved response that is pretty effective in getting predators to let them go. Sure, an animal could bite instead, but that's aggressive and likely to earn an aggressive response. These animals are generally built for flight, not fight, and peeing is a submissive response. But for humans and other creatures higher on the food chain, being an apex predator means we'll have much different responses than animals that are not apex predators.
Bonus: you could use this information to portray the opposite. Sometimes authors want to show how badass their character is by having them be completely unfazed by something another character finds terrifying. You could have your character walking into battle commenting that he/she is starving and hopes to get something to eat after finishing with this nonsense, or something along those lines.
I know I blog about statistics a lot on this blog, but I'm always thrilled to talk about my discipline too! Any psychology topics you'd like to see addressed here? (Or any tropes you're tired to seeing?)