The judge in the murder case against Jason Van Dyke is set to hear arguments Thursday on whether to allow trial testimony by a Florida-based psychologist who has described “alterations” in what police officers perceive as they kill people.

Attorneys for Van Dyke, the Chicago officer who fatally shot Laquan McDonald, are planning on Dr. Laurence Miller as an expert witness to buttress their contention the killing was an act of self-defense.

But special prosecutor Joseph McMahon, in a motion released to the public last week, said Miller’s testimony about Van Dyke’s perceptions during the shooting would be “self-serving hearsay.”

“The jury does not need Dr. Miller to tell them what thoughts were going through the defendant’s mind before and during the shooting, because only the defendant can know that information,” McMahon argued in the motion filed March 8.

Miller’s name and identity do not appear in court documents available to the public. Cook County Judge Vincent Gaughan has blocked release of defense filings about planned expert witnesses. The judge ordered Miller’s name to be redacted in the prosecution motion.

But attorneys have referred to the proposed witness by last name in court.

Miller, a clinical and forensic psychologist and police educator based in Boca Raton, confirmed he has been retained by the defense team. He said he has not been called to appear at Thursday’s hearing. He declined to comment about his planned trial testimony.

Altered perceptions

Van Dyke fired 16 shots into McDonald, 17, on Oct. 20, 2014. A video of the shooting, recorded on a police dashboard camera, was withheld from the public until a judge ordered Mayor Rahm Emanuel’s administration to release it more than a year later.

The video shows Van Dyke opening fire within seconds of leaving his police SUV as McDonald, who was carrying a knife, walked away from officers. The day the video was released, prosecutors charged Van Dyke with first-degree murder. Grand juries added charges of official misconduct and aggravated battery.

After the video release, the city disclosed reports by officers on the scene that depicted McDonald as moving threateningly toward Van Dyke with the knife before the officer opened fire.

Separately from Van Dyke’s case, two police officers and a detective were charged with conspiracy in an alleged cover-up for him.

In 2016, meanwhile, Miller gave Van Dyke a psychological examination.

The defense plan, according to the prosecution motion, is for Miller to testify about reactions by officers during and after shootings by cops — about their altered perceptions, thinking, behavior, and memory.

Miller has written on those topics.

“Most officers who have been involved in a deadly force shooting episode have described one or more alterations in perception, thinking and behavior that occurred during the event,” Miller wrote in a 2006 article in International Journal of Emergency Mental Health . “Most of these can be interpreted as natural adaptive defensive reactions of an organism’s nervous system to extreme emergency stress.”

Those reactions, Miller wrote, range from time-perception distortions to “tunnel vision” in which the officer focuses on just one thing, typically a suspect’s weapon.

The article says officers who use deadly force can also experience “some form of perceptual and/or behavioral dissociation.”

“In extreme cases, officers describe feeling as though they were standing outside or hovering above the scene, observing it ‘like it was happening to someone else,’” Miller wrote. “In milder cases, the officer may report that he or she ‘just went on automatic,’ performing whatever actions were necessary with a sense of robotic detachment.”

Miller made similar points in a 2015 article, “Why Cops Kill: The Psychology of Police Deadly Force Encounters,” published by the journal Aggression and Violent Behavior.

Colorable basis

Civil-rights attorney James D. Montgomery Sr. said Miller’s testimony, if allowed into the trial, would help the defense argue the officers on the shooting scene “truly believed they were under imminent attack” by McDonald.

Montgomery, who served as Chicago corporation counsel under Mayor Harold Washington, called the plan for Miller to testify an attempt to “take away the sting of a clear video showing there was no justification for the shooting.”

“Police officers who have shot people, unprovoked, have been acquitted by juries all over this country because people believe in the police and they don’t believe in criminals,” Montgomery said. “The defense wants to get some evidence to give a trier of fact who may be inclined to acquit Van Dyke a colorable basis for doing so.”

Van Dyke’s attorney Dan Herbert declined to comment and pointed to a Gaughan decorum order that bars the parties from publically addressing the case outside the courtroom.

Gaughan said Thursday’s hearing about the admissibility of Miller’s testimony will be closed to the public. The judge held the case’s first closed-door hearing last week.

Gaughan has said the trial will take place this summer but has not announced a specific date.

Chip Mitchell covers law enforcement for WBEZ. Follow him @ChipMitchell1.