Deep within every one of us is a brain structure called the Reptilian Complex. It is an ancient and powerful piece of biological machinery, having been part of every vertebrate creature ever to walk the earth or swim the seas. It’s in us, too, and handles the jobs we can’t be bothered to think about all the time, like keeping our hearts beating and breathing.

But for writers, the Reptilian Complex has a much more important job. It is also responsible for the Fight-or-Flight response, the basic survival instinct of all animals—people included—when threatened or cornered: fight, or run away.

Fight-or-Flight and Depression

Readers of this blog will well remember that depression is one of the five stages of grief that give such a useful roadmap for how characters respond when confronted with misfortunes. Had I been cleverer when writing that article on depression, I would have realized the connection between depression and the fight-or-flight response. Alas, I wasn’t, but better late than never.

What keeps people stuck in the depression stage, you’ll recall, is that anxious feeling of not seeing a way out of a bad situation. “Doomxiety,” I called it. In hindsight, this now seems obvious to me, but I didn’t see it at the time. Feeling trapped triggers the Reptilian Complex to initiate that fight-or-flight response.

I want to talk about flight first, because there’s a stronger connection to that sense of feeling trapped. The core of five-stage depression is not seeing any way out of a bad situation, so flight makes sense: running away, in one form or another, is a means to create a way out.

When do characters flee?

But notice, people don’t just immediately run away from bad situations all the time. In fact, flight is usually a last resort, and that’s because flight always involves sacrifice. The choice to run away always means leaving behind something that is of value to the character; if this weren’t so, the character wouldn’t have felt trapped in the first place, because the flight option—which was always there—would have had no down side.

The only thing keeping the character from always fleeing is an unwillingness to leave behind the parts of that bad situation that matter to them. Take bad marriages, for example. People stay in bad marriages all the time, because even if they’re totally unhappy with their spouse, there’s still something about the situation that the person values. Something that makes the flight option unacceptable. Maybe they can’t stand to leave the children, maybe the person came from a poor background but married into money and can’t stand the thought of being poor again, whatever. Something’s keeping them there.

Only when the situation becomes so bad that it outweighs the good parts will a person—or a character—finally choose to run away.

How do characters flee?

When a character finally opts to leave the bad situation behind, no matter the cost, he or she has some options. These fall into three broad buckets:

• Panicked flight. This is literal fleeing, a rushed, haphazard, often terrified physical exit from a situation. Lots of yelling and screaming, flailing of arms, you get the picture. This kind of flight is perfect for situations where the character is threatened, but doesn’t have any strong emotional investments in the situation itself. Let’s say your character is walking down the street on his way to a cafe for lunch, when a mugger jumps out of an alley brandishing a knife. Sure, losing out on lunch is, technically, a sacrifice but it’s not a big one. Why wouldn’t he run? Especially if the mugger looks a bit on the fat-and-slow side, why wouldn’t the character run? What earth would make him stay and fight? I mean, is he so committed to getting a ham-on-rye that he’s willing to risk getting knifed? Of course not. In situations like this, a sudden threat that is not coupled to a significant sacrifice, flight makes perfect sense.

• Methodical flight. This is a planned escape from a bad situation. Maybe it’s a jailbreak, but this fits any situation where the situation has become so bad that uprooting one’s whole life (or some significant chunk of it) isn’t too much of a sacrifice. These are the dads who go out for cigarettes and just never come back, the employees who just walk out even with no new job to go to. The amount of planning may vary; your typical jailbreak novel will involve an enormous amount of planning, while the deadbeat dad may simply have left with nothing but a wallet and a gym bag hastily stuffed with clothes and a razor. The difference is a lack of panic. This kind of flight is appropriate when the sacrifice is great, but there is no particular rush to escape. Use this when the character has plenty of time to consider the situation before deciding to flee.

• Existential flight. This, in a word, is suicide. Suicide, when the result of five-stage depression, is a form of flight. People and characters do this when they’re so convinced there’s no way out of their bad situation except to stop living. This is when a character believes that even picking up stakes and starting over somewhere else won’t actually get them out of the bad situation. Obviously, this is the ultimate last resort, and you should think very, very carefully before putting a character on that path. For one thing, we shouldn’t make light in our novels of what in real life is one of the worst kinds of personal tragedies. For another thing, suicide isn’t going to work in your novel unless you’ve created a situation where the sacrifice—literally everything in the character’s life including all possible future experiences—isn’t enough to outweigh the pain of the bad situation the character is in. To make that believable in a novel is a pretty tall order. There’s no question suicide has its place in literature, but—and I apologize for the wording here—it’s not easy to do it right.

When do characters fight?

The fight half of Fight-or-Flight also relates to the depression stage, but in a different way. Fighting can be the key to reaching acceptance. You can create some powerful moments when the trapped feelings behind depression trigger a fight response. These are moments when the character says “there must be some way out of this, and I’m going to find it!” Tons of great drama there. If you’re looking for a way to get your character into the acceptance stage, this can be a wonderful option because—assuming your readers are actually rooting for your character—they want to see the character reach acceptance. They want to see him push through, survive, win.

You can bring on moments like this in a million different ways. You could have a character fall back on pride or stubbornness as a reason not to flee. You could have the choice to fight come from the culmination of an inner character arc: “Daddy always said I was a no-good loser, but I’m not, damn him, I’m not! And I won’t be now!”

However you bring it on, the common theme behind all of these fight responses is the character realizing that the sacrifice attached to fleeing is just too great. The stubborn, prideful character isn’t willing to sacrifice self-image. The child of the abusive father isn’t willing to sacrifice the personal growth he has already made. Whatever it is, fighting is what characters do when you’ve coupled their bad situation to something of extreme personal value to them.

When our characters realize that nothing is so bad as to be worth that level of sacrifice, that’s when they fight back.