On the way out of a photo booth set up for a "Mother's Day" event at a restaurant, Linda Maher tripped and fell, hitting her head on the corner of a wall.

Her lawyer sued and asked a jury for $11 million. But defense attorney Casey Quillen had come prepared: She filed a motion in limine to prevent Maher's lawyer from using what she called "reptile theory" strategies at trial. Defense attorneys say plaintiffs attorneys use the theory to incite jurors' survival instincts, emotions and fears by appealing to their "reptilian brains," often in reference to safety or community concerns. They do this to obtain larger, and often unexpected, jury awards, sometimes referred to as "nuclear" verdicts, defense attorneys say.

Sounds far-fetched? It's not. On May 17, the judge granted Quillen's motion, and the jury came back with a defense verdict.

Quillen, of counsel at Ruebel & Quillen in Westminster, Colorado, said the ruling was critical to winning the case.

"If they had presented a different line of questioning or done the whole 'reptile theory' buildup, we may have been faced with a completely different verdict," she said.

She's not alone. Defense attorneys increasingly are slipping in "reptile theory" motions prior to trial or, in some cases, in motions for new trial, particularly in the past five years. And they've won some recent decisions. The concept, popularized by a book for the plaintiffs' bar called "Reptile: The 2009 Manual of the Plaintiff's Revolution," has popped up in defense bar seminars and events—it's even the subject of a copyright battle between two jury consulting firms over articles they published.

"There has been a big effort by the defense bar to try to preclude those type of arguments because what they end up doing is presenting a jury that is scared by the time they get to the verdict stage, and they want to award more damages to punish the defendant, which is not proper," said Rachel Mihai, a partner in the Newport Beach, California, office of defense firm Bremer Whyte Brown & O'Meara. "And the plaintiffs attorneys might put a fear in the jury that, if they don't make a decision, that we as a society will see this condition come up again and again, and they have to be responsible as jury members."

But plaintiffs attorneys insist that "reptile theory" is a valid strategy to address jurors' community conscience or bring up safety rules that corporations violated.

"From the plaintiffs' perspective, laws are rules, so you talk to the jurors about violating the law or the rule. There's nothing improper about that," said plaintiffs attorney Tom D'Amore, of D'Amore Law Group in Portland, Oregon. "That's what the whole tort system is all about: to keep our society safe and conscious of the community."

Sam Cannon, the lawyer who represented Maher, who slipped in the Colorado restaurant, said he disagreed with the judge's ruling granting the "reptile theory" motion.

"I've never read 'Reptile' and don't really buy the theory particularly, but in a case where the claim is the owner did something unreasonably dangerous, I tried to talk about what they should have done to make the place safer, and that's what lead to the motion," said Cannon, of Cannon Law in Fort Collins, Colorado.

What is "reptile theory?"

"Reptile theory" usually raises its head in run-of-the-mill cases, like those over trucking accidents or slip-and-fall incidences.

"Some plaintiffs lawyers swear by this 'reptile theory' and follow it to the tee," said D'Amore, who has been to several "reptile programs," including at the American Association for Justice, the largest plaintiffs bar organization. On Oct. 11, he defeated a motion for new trial, alleging in part that he used "reptile theory" arguments during closing argument in a wrongful death case over a car accident in Oregon. The jury awarded $26.5 million.

Under "reptile theory," plaintiffs attorneys often focus on safety rules, industry standards or employer handbooks, and whether a defense witness, often the corporate representative, followed them.

The questions, however, often stray from the standard of care at issue, Quillen said, focusing instead on getting a "visceral reaction from the jury based on witness testimony."

"Usually, they're termed in questions you, as a rational human being, can't disagree with, and then they build a box around the witness to get the witness to admit whatever they did was horrible and awful and endangers the public," she said.

The tactic, however, does not always work. Quillen said the facts of the cases and the skills of the plaintiffs lawyer are additional factors that influence whether the strategy works on jurors.

How Judges Have Ruled

In general, judges have been reticent to grant "reptile theory" motions. In many cases, judges have called the motions either premature or too vague.

"Defendants complain about amorphous and ill-defined concepts rather than specific evidence which they believe plaintiff will introduce or arguments which they believe plaintiff might make," wrote Judge John deGravelles of the U.S. District Court for the Middle District of Louisiana in a 2017 decision denying a "reptile theory" motion in a car accident case in Baton Rouge, Louisiana. "The court is being asked to rule on abstract and generalized hypotheticals."

Last year, Judge David Faber of the U.S. District Court for the Southern District of West Virginia refused to grant a "reptile theory" motion in a public nuisance case brought by eight residents who lived within a half-mile of a hog farm in North Carolina. The defense motion, he wrote, was full of "unnecessarily inflammatory language" that "could have been made in a more professional and specific manner." A jury in that case awarded more than $100,000 on Dec. 12.

In D'Amore's case, Magistrate Judge Patricia Sullivan of the U.S. District of Oregon, in refusing to grant the new trial motion, wrote that, "references to the conscience of the community are not necessarily problematic."

But some judges have sided with defendants, many of which are better poised to strike at "reptile theory" arguments.

"When the 'reptile theory' first came on scene, there were a lot of motions in limine early in the case, before depositions and trial, trying to preclude any questions that would fall under 'reptile theory,'" Quillen said. "But nobody understood it well enough, and nobody was outlining specific questions that would be objectionable in explaining to the court as to why these questions should not be allowed in the first place."

She said she added more details in her "reptile theory" motion in the Colorado restaurant slip-and-fall case, for instance. On May 17, Larimer County District Court Judge Julie Kunce Field granted the motion, barring plaintiffs attorneys from asking the restaurant owner questions "regarding safety standards or public safety."

Mihai filed her first motion in limine to bar "reptile theory" questions in a case alleging her client had discriminated against renters with children by evicting them from an apartment building in Riverside, California. She said she got the idea to mesh "reptile theory" with the Golden Rule, which bars attorneys from inviting jurors to imagine if the alleged wrongdoing had been done to them.

On March 29,  Judge Jesus Bernal, of the U.S. District Court for the Central District of California, granted the motion, agreeing with the defense that "reptile theory" arguments are "those which ask the jury to place themselves in the shoes of a 'reasonable person.'"

The jury came back with a defense verdict on April 5.