Inside an old warehouse on Washington State University's Spokane campus, police officer Nick Briggs is being fitted with an imaging device to monitor what's happening inside his brain as he makes life and death decisions.

"What it does is measures the oxygen in the blood in your prefrontal cortex," Dr. Lois James tells Briggs. "In layman's terms, that gives us an idea of how hard you're working at the various tasks."

As he steps into the V simulator, Briggs is armed with an actual police issued handgun -- a Glock -- modified to shoot a laser instead of bullets.

James puts him through a series of high anxiety scenarios based on real life situations that play out on a huge virtual reality screen. Inside this simulator, Briggs will be tested as he decides whether to shoot or not to shoot in the face of danger -- a decision he said he takes very seriously.

"There's a high degree of stress, thinking that it's real. You're thinking about ensuring the citizens involved are safe, you're thinking about your personal safety," Briggs said.

The exercises are designed to test the limits of human judgment.

"We really want to understand and provide knowledge and understand the dynamics of deadly encounters, because very little is really known about the challenges officers face in these split second life or death decision making moments," James said.

The Violence Confrontation Lab at WSU is the only one of its kind in the world that takes data from actual officer-involved shootings and recreates frighteningly realistic scenarios playing out on a huge virtual reality screen. The research is partially funded by the U.S. Department of Defense.

James oversaw the creation of 60 scenarios used in the simulator -- compiled based from 35 years of information collected by the FBI about actual police involved shootings. The scenarios were filmed on real-life locations using actors. Each scenario begins with a briefing similar to what an officer receives on patrol from a dispatcher.

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In one domestic violence scenario, the simulation informs Briggs: "You receive a domestic disturbance call from a distraught person who says their spouse is being abusive and there are weapons in the house. Do you understand?"

Briggs signals yes. As he enters the home portrayed on the virtual reality screen, Briggs sees a woman being assaulted. Briggs orders the man to stop: "Sir, let me see your hands," he orders.

The man ignores him and raises what looks like a gun. Briggs shoots.

"Reaction time was zero point six seconds, so a little over a half a second from the gun becoming apparent, to the officer firing the first shot," James said as she reviewed the scenario later. And Briggs didn't shoot once. He fired three shots in a little over one second. That's how fast things unfolded.

It was the right decision because Briggs took down the suspect without harm to himself or the woman being assaulted.

His body reacted to the scenario as if it were real.

"I was sweating, my heart beat was elevated, my pupils were dilated—all those stress responses which is great because that's what it's going to be like in real life," he said.

In another scenario, Briggs fails to stop a suspect, after which he can't seem to shake it, playing out his mistake over and over.

"I wasn't able to react fast enough, it even bugs me now doing the interview that I wasn't able to react fast enough in order to prevent her from getting hurt," he said.

Across the country, officers are making split-second decisions, and the researchers at the Violence Confrontation Lab are splitting those seconds into tenths and hundredths of seconds to understand the science behind it all. James says they're trying to identify what officers can do to make good decisions, and to minimize harm to themselves and others.

It's possible the research could even help police departments identify which officers are better equipped to manger the most difficult, dangerous, high stress situations.

"If we can say for example that Officer A is using 70 percent of his cognitive resources, we have good information there that says that Officer A might be able to handle something else that's thrown at him. Whereas if Officer B is using 100 percent of his resources, throwing something else into the mix, might not work," James said.

More than a hundred Spokane police officers have gone through the simulator. While the data is still being analyzed, James said the researchers hope to learn whether the use-of-force training being used by police departments really works.

"If we can better understand the dynamics of deadly encounters and understand what happens to officers when they're in those encounters, we can take that knowledge and apply that in the field. We can use it to inform training we can use it to inform policy," James said.

Spokanes Police Chief Frank Straub said he believes having officers take part in the research (which they do on their own time and without compensation) is already paying off for the department and the citizens they police.

"What we saw in 2014 is a 22 percent reduction in our use of force incidents. We're seeing I believe the benefits of data and science informed training on our officers their decision making and the amount of force that we're using in our interactions with the community," Straub said.

The research is still being analyzed, but Straub and Dr. James plan to present some of the preliminary findings in May to a research advisory board of the International Association of Chiefs of Police, which is co-chaired by Laurie Robinson, professor of Criminology, Law, and Society at George Mason University and former Assistant Attorney General for DOJ's Office of Justice Programs. Robinson also serves on President Obama's Task force on 21st Century Policing.

Nick Briggs is already convinced the research is helping. He's 29 years old and said he has never used lethal force during his eight years as a cop. He believes the lessons he's learning in the lab will transfer to the real world, if and when he's forced to decide: shoot or don't shoot?

"At our core, we're good people that don't want to hurt anyone," Briggs said.