JACKSONVILLE, Fla. -

The defense in the Michael Dunn case were unsuccessful in bringing the fight-or-flight defense into the testimony of his murder trial. The judge wouldn't allow someone the attorney considered an expert to testify.

Early in the Tuesday hearing, the defense counsel called a counselor up to the stand who was a self-proclaimed expert on fight or flight, but the judge didn't allow the man's testimony because he wasn't considered an expert by the court.

One local psychologist said fight or flight is a reaction everyone has, and it can be irrational or unknown how it will manifest until a person is in a life-threatening situation.

"The fight or flight response is an automatic response the body makes in order to survive when somebody experiences a threat," said Justin D'Arienzo, a clinical psychologist with no link to the trial. "The body makes rapid calculations that's often out of our conscious control."

That's what defense lawyers would like to get across, that Dunn was fearing for his life and his shooting of Jordan Davis was beyond conscious control.

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"The body takes over, there's a rapid calculation, a decision is made and we respond," said D'Arienzo.

D'Arienzo said anyone in a dangerous situation will go into fight-or-flight mode. That's one reason defense lawyers have hit hard on the theory that the teens had a gun, which caused Dunn to pepper the red Durango with bullets in fear of his own life. There is no proof though and no gun was ever found.

"It can be often that someone acts impulsively or does something that's questionable when people want to understand why someone would act a certain way in a threatening situation," said D'Arienzo.

D'Arienzo said there are actually three manifestations of fight or flight: fight, flight or freeze. He said men typically become more aggressive while women are more likely to flee or diffuse the situation.