Personal injury lawyer Paul Luvera has written about Applying Reptile Concepts in Trial—describing how plaintiffs’ lawyers should appeal to jurors’ reptile brains.

The reptile brain is the core of the human brain, sitting right at the top of the spine surrounded by the later-developing dog brain and ape brain. The reptile brain is a survival engine, concerned only with survival: kill, eat, mate, flee. To get through to the reptile brain, you show it a threat, a way to mitigate or resolve that threat, and a greater threat that could otherwise result. In the example of a personal injury trial, says Paul, the plaintiff’s lawyer wants to make the points that:

1. The defendant’s conduct threatens everyone’s safety;
2. A proper verdict for the plaintiff will reduce the danger; and
3. If a proper verdict for the plaintiff is not given, the danger will be increased.

Easy to see how these apply to many criminal trials (at least trials involving mala in se, rather than regulatory offenses), right? Prosecutors use something like it in every jury trial—make the jurors afraid, then give them a way to be safer—though probably without realizing that they are appealing to the reptile brain.

There is much research and thought being conducted into how to win plaintiff’s personal injury trials because there is so much personal benefit to the lawyer in winning one of those trials. Civil defense lawyers and prosecutors aren’t putting as much effort into finding new ways to try cases as plaintiff’s lawyers are.

Nor are criminal-defense lawyers—most criminal-defense lawyers are struggling to make a comfortable living, and those that aren’t don’t necessarily have the tools or inclination to spend their free time figuring out how to try cases smarter. Sometimes we borrow from the personal injury lawyers who, like us, are representing human beings.

Unlike us, though, the personal injury lawyers are fighting over a quantifiable form of justice—justice as dollars—and they are on the offensive. So often (as, I contend, with the Reptile Trial) we can’t use their science to our clients’ benefit.

Not, at least, directly. But if we recognize that what our adversaries are doing is (whether consciously or not) appealing to the jurors’ reptile brains, then we can try to a) make a stronger appeal to the reptile brain; or b) disengage the reptile brain, and engage the dog brain or ape brain. Neither is an easy proposition.

First, jurors expect the government to protect them from people doing bad things and expect us to try to protect people doing bad things. So in order to appeal to jurors’ reptile brains ourselves we have to reverse these expectations. We have to show why the government’s conduct threatens everyone’s safety. While it is often true that the government’s conduct threatens everyone’s freedom, such an argument is an appeal to the simian brain, and can’t serve to divert the reptile brain. It’s less often arguable that the government’s conduct presents a threat to jurors’ safety. If you can’t get the jury thinking that they have to protect themselves and their loved ones from the government, their reptile brains aren’t going to help you.

Second, evolutionary biology has given the reptile brain veto power over the rest of the brain when there is an imminent threat. Until the threat is resolved, the mammalian and simian parts of the brain—the parts that deal with emotion, complex social interaction, advance planning—don’t get a vote.

Fortunately, our higher brains have a mechanism for taking control back from the reptilian brain. We even have a universal signal to tell our fellow humans when this has been done.

The mechanism is incongruity. The reptile brain is simple, one-tracked and without nuance. It can’t handle incongruity or surprise. When the reptile brain encounters something unexpected, it hands the job off to more complicated parts of the brain (“okay, mammalian brain: I’ve never seen one of these before. Should we flee it or mate with it?”).

So the criminal-defense lawyer can destroy the government’s reptilian argument by revealing a surprise that doesn’t fit in with the government’s reptilian story (an argument for maintaining Nasty Little Surprises until trial). In the words of trial consultant Dennis Elias, “Suspending disbelief & creating doubt that leads to curiosity and surprise is the art of the criminal defense attorney.”

And what’s the universal signal that tells us when our lizard brains have handed off to our mammalian and simian brains? It’s laughter. According to both the incongruity and relief theories of laughter, the surprise that gets us out of our reptilian brains is a trigger for laughter, either because the incongruous is inherently funny or because we are relieved to discover that we are out of danger. Find the surprises in the case, and reveal them to the jury, and you can get them using their higher brains. Do it in jury selection, if you can—take some part of the case that the government hammered on in its jury selection, and show the jury why things aren’t as they expect. Make them laugh, and make it a Simian Trial.

Once you’ve got the jury using their more complex brains, you want to keep them there. How? Two ideas.

First, the government’s Reptile Trial is a Things-That-Go-Bump-In-The-Night Trial. Things that go bump in the night can seem silly in the light of day, and the government’s perceived threat can seem silly to the mammalian brain.

Second, the rule of Reptile Trials is “simplify, simplify, simplify.” Since the lizard brain doesn’t deal with complexity, the rule of Simian Trials is the opposite.

Complexify, complexify, complexify.

(If you’ve arrived here from Overlawyered, you might be interested in The Ethics of Pathos, Part I.)