Kim Potter's lawyers are portraying her mistake -- fatally shooting Daunte Wright with a firearm when she says she meant to grab her Taser -- as an "action error."
This is when "we do one thing while meaning to do another," according to her defense attorney Paul Engh.
"They are ordinarily dismissible, but they become quite important when what happens is catastrophic," Engh said.
Potter is the former Brooklyn Center police officer charged in the death of Wright, a 20-year-old Black man who was fatally shot during a traffic stop in April.
Dr. Laurence Miller, a psychologist, testified in Potter's trial how action errors may play a role in making mistakes in daily life. Like writing the wrong date down or putting in an old password into a computer, ingrained habits sometimes take over and people do what is routine rather than what they actually meant to do, Miller argued.
Miller described an action error in more detail for the jury deciding whether Potter is guilty of first- and second-degree manslaughter. She has pleaded not guilty.
"In an action error, there is a sequence of responses in which an intended action has an unintended effect ... [it] does not have to do with outside interference, willful neglect or conscious manipulation," Miller said.
MORE: Kim Potter trial updates: Potter testifies in her own defenseHe added, "You intend to do one thing, think you're doing that thing, but do something else and only realize later that the action that you intended was not the one you took."
He said these actions occur all the time.
"There are three main factors," Miller said. "[A] person is under an extreme degree of stress. But what's interesting is that the arousal [does not] necessarily cause the action error."
The second main factor, Miller said is hyper-focus, "when you are in an extremely emotional state, you zero in on the thing that seems to be most dangerous, most critical, and because you're zeroing in on one particular aspect of that situation, the thing that is causing in your mind the greatest parallel in danger, you're tuning out everything else."
Then comes the third factor, which is a "distraction of attention," Miller said, "because you're zeroed in, you're tuning out everything else."
MORE: Kim Potter trial: Prosecution tears into Potter's police trainingThe prosecution is arguing that Potter was reckless and negligent in the killing of Wright.