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According to a Force Science Institute study [full report after the jump], a police officer’s memory after a shooting is highly unreliable. Same goes for you. That’s why you should never agree to a post-defensive gun use police interview without a lawyer present (but do provide details that can help the police apprehend criminals or identify witnesses). “Investigators need to remember that an officer who misses or misstates information about an event that later becomes significant is not necessarily being deceptive or self-serving,” the report recommends. That’s true for both cops and [non-LEO] citizens, although you’re hardly likely to get the same slack as brother officer. Just sayin’ . . .

Force Science writes:

A profound irony is revealed in a major new study of human performance under stress, sponsored by the Force Science Institute. Namely: At the most critical moment in a force encounter–the moment that perhaps is most important for an officer to describe accurately–the officer’s memory of certain key details about what happened is likely to be the least reliable.

In particular, the first-of-its-kind study documents that officers actively involved in armed confrontations often have difficulty accurately answering questions about a suspect’s weapon, including whether a weapon was visible in the offender’s hand, how the weapon was presented, and even whether the suspect fired it during the incident.

A peer-reviewed report on the study has been accepted for publication by the American Psychological Assn.’s prestigious journal, Law and Human Behavior. This will be the eleventh peer-reviewed scientific journal to have published law enforcement-related studies by the Force Science Institute.

An international team that included Dr. Bill Lewinski, FSI’s executive director, conducted the research. Lead author of the findings is Dr. Lorraine Hope, a professor of applied cognitive psychology at the University of Portsmouth in England. (Dr. Hope led another landmark FSI study several years ago that tested the functionality and memory of officers who were physically stressed to the point of exhaustion. Click here to read about it.)

SPLIT ASSIGNMENTS. Tested in the current study were 64 officers from an urban area of Canada, ranging in age from 22 to 59 and in experience from newly on the street to nearing retirement. They were randomly divided into two groups –Active (“Operational”) Officers and Observer Officers–and then paired with a member of the opposite group. One team at a time, the participants were then immersed in a violent, stress-inducing scenario.

As the action unfolded, the Active Officer, outfitted with a training gun loaded with blanks, was to respond as if experiencing the scenario on duty, while the Observer Officer was simply to passively watch what happened. Among other things, the researchers wanted to see what, if any, differences there would be between accounts of the experience given later by the paired participants.

The experiment involved a multi-stage procedure, which stretched over nearly a week before examination of all pairs was completed.

First, each pair watched a two-minute “briefing video,” purported to be cell phone footage taken in a college classroom. With a class in progress, a disgruntled student enters the room and engages the professor in an argument about poor grades. The perpetrator becomes increasingly agitated, draws a knife from his pocket, and takes the professor and another student hostage, while people flee from the scene.

Then from inside the “classroom,” each officer team, “dispatched” to the location, was exposed to the “experimental scenario,” lasting about four minutes. Standing side by side in designated positions, the officers initially are able to see the suspect threatening his hostages on “live” footage of the “on-going” incident from a closed-circuit TV camera trained on the hallway outside. Within seconds, the suspect bursts into the classroom, using a hostage as a shield and holding a knife to his captive’s neck.

After issuing various demands, he frees the hostage, throws the knife to the ground, and retreats back to the hallway. There, again visible on CCTV, he can be “seen tucking a gun into the waistband of his jeans.”

In a “final live interaction,” Hope writes, the suspect re-enters the classroom “in an agitated manner, goading the officers to shoot him.” At a point where he has turned his back on the officers, he suddenly spins around toward them with his hands moving toward his waistband and then his hands were suddenly thrust forward in a shooting position toward the officers. The gun, however, remains undrawn throughout. The assailant immediately pulled his hands into a hidden posture under his body as he fell.

The scenario ended once the Active Officer responded to this movement.

PUCKER FACTOR. This scenario, Hope explains, was developed through “extensive discussion with firearms instructors and police trainers” to be realistic and challenging enough to create “a natural physiological stress response” and complex enough that “the participants could be questioned about [it] in detail.”

That the scenario was a successful high stressor was well documented by cardiac monitors. During the scenario, Lewinski told Force Science News, the average Observer Officer’s maximum heart rate doubled, and the Active Officer’s pulse rocketed “significantly higher” yet.

An even “more reliable measure of stress,” he explains, was the fact that the officers’ rapid heart rate sustained consistently over a period of time, indicating the strong influence of stress chemicals. Again, this distinction was significantly more pronounced in Active Officers, who were personally responsible for dealing with the situation, compared to mere Observers.

MEMORY TESTS. For about 45 minutes after the scenario ended, the two officers were separated to avoid their discussing the incident. Then, with no imposed time pressure, they independently engaged in a two-part memory test.

1) In a “free recall” exercise (somewhat mimicking a cognitive-style interview) they were instructed to write down “as much information as they could remember” about the initial video briefing and the main scenario, making their accounts “as complete and accurate as possible” without guessing.

2) They then were asked to answer an extended list of 94 “closed questions” modeled on the style and content “often adopted by investigators.” A few questions asked for “subjective assessment” of the suspect, such as what his demeanor was. But most of these sought factual information about the briefing and live role-playing that could be verified with contemporaneous digital recordings.

A subset of 14 closed questions was deemed to be of supreme importance. Hope writes: These questions “were identified by legal and police training advisors as critical…with respect to an officer’s understanding of the final stages of the scenario and underpinning any justification to shoot.”

Specifically, these key inquiries focused on determining what the Active Officers and Observers remembered about the perpetrator’s action, his weapon position, and officer response.

On average, Hope reports, the participants took about two hours to complete the recall tasks. The results were carefully evaluated for amount and accuracy of information.

EVOLVING DISPARITIES. “Our findings showed a dramatic progression of memory impairment about what took place,” Lewinski says, “especially for the Active Officers.”

In freely recalling details about the briefing video, the researchers found on average that there was no significant difference between the amount or accuracy of information remembered by Active and Observer Officers.

However, significant free recall differences arose regarding the action as the officers became personally present in the intense, escalating live experimental scenario. Although the accuracy of what was recalled was essentially the same for both types of participants, Active Officers reported a significantly lower quantity of correct details than Observer Officers, Hope writes. In other words, the ability of Active Officers to describe what happened became sketchier.

In handling the “critical subset” of closed questions, particularly details involving the suspect’s weapon, disparity between the two officer groups became decisively evident. The overall recall of both groups degraded, but Active Officers provided far fewer correct answers and significantly more incorrect answers than Observers regarding the weapon “in the final moments of their interaction,” a particular area of memory “vulnerability,” Hope reports.

The average Active Officer dramatically trailed his Observer partner in accurately answering such questions as:

• What happened when the culprit turned towards you?
• Was there a weapon in his hand at this point?
• If yes, describe how he presented the weapon?
• Did the culprit discharge a weapon during the incident?
• What was the position of the culprit’s gun when he was impacted by round(s) from the officer? (Of Active Officers, 85% discharged their weapon during the scenario.)
• Where was the [suspect’s] gun at the end of the scenario?

One particularly startling finding emerged from the researchers’ tally. Despite spinning and moving his hands in a provocative manner, the suspect kept his gun tucked in his waistband throughout. Yet, Hope writes, roughly 20 percent of the participants–Active Officers and Observers alike–“explicitly reported” that the suspect “pointed a weapon at them/in their direction in the final scene” of the scenario.

She notes: All officers who reported seeing the weapon pointed at them “expressed surprise when told that was not possible.”

INTERPRETATION. Further research is needed to fully explain the phenomenon of seeing a gun that wasn’t there, Hope says. However, it seems likely that “expectation-driven” judgment of the suspect’s movement within a violent setting was involved. Or, to cite a cynical view, perhaps officers reported seeing a pointed gun under pressure to justify their own use of lethal force.

“Deliberate fabrication…lies beyond the scope” of the study, Hope writes. But the findings reveal other important and less controversial realities about “honestly held” memories that should be taken into consideration by investigators of officer-involved shootings and other high-intensity events, Lewinski says.

“Considering that Active and Observer officers stood side by side while exposed to the same threatening scenario yet had some critically different memory qualities tells us a lot about the unique pressures placed on officers who are forced to perform under high-stress conditions, compared to other eyewitnesses,” Lewinski says.

The impairment of Active Officer recall regarding weapon details during the most critical part of the scenario may be attributed to a couple of related factors, the researchers suggest.

• Active Officers had higher levels of stress throughout the scenario and that stress undoubtedly would have been at its maximum when the threat level seemed greatest. It has been solidly established in scientific literature that the greater the stress, the more likely that memory will be flawed.

• At the same time, the added cognitive load required by Active Officers to handle their time-pressured tactical and decision-making responsibilities would also have been at its greatest in the rapidly escalating final scene. This combination may have disrupted the ability of those officers to detect and thoroughly process details about the suspect and his weapon.

• After a real-world shooting, where the stakes obviously are much higher than in a research scenario, “it is reasonable to assume that officers may also experience stress at the reporting stage,” Hope writes, thereby potentially compounding the matter.

In summary, Lewinski states: “This study is added evidence that to expect an officer actively involved in a life-threatening encounter to resolve the action and completely grasp and later accurately describe in detail everything that happened may be expecting too much from the average human being.

“Investigators need to remember that an officer who misses or misstates information about an event that later becomes significant is not necessarily being deceptive or self-serving.”

In the words of the study: In regard to investigative procedures and policies, it is important that the treatment of operational witnesses (Active Officers) be “well-informed [about] the malleability of memory and appreciate the necessity for careful and ethical memory elicitation practices….

“[I]t is critical that practitioners in the legal system, whether lawyers, prosecutors, or judges, are cognizant of the potential for naturally occurring memory errors, gaps, and inconsistencies among all witnesses but particularly operational witnesses, such as armed officers [in] challenging incidents….”

Across several pages in their report, incidentally, the researchers provide a valuable summation of memory findings by other scientists in recent years that help explain why it is “difficult to predict what will be remembered from stressful events.”

At this writing, the date for Law and Human Behavior to publish the study has not been set. We’ll report when the study is available for access in full.

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    • Thanks! Here’s the NYT article

      “Dr.” Lewinski has a mail order Ph.D. from the Union Institute: “Adult distance learning center offering nontraditional degree programs, adult online degrees, online bachelor’s degrees and low residency degrees.”

      Force Science Institute claims it is “comprised of a world-class team of physicians, psychologists, behavioral scientists, attorneys and other leading professionals.” but only Lewinski is visible.

      Hired gun for police unions: the best justice money can buy.

      c.v. @

    • That’s a nice hit piece, but the only real complaint I found in it is that his expert testimony is often irrefutable. In fact it ends with a nice story of how his testimony apparently changed the mind of a jury who seemed hell bent on convicting an innocent man. Sounds more like a badass, to me.

    • Just because something gets published in a “refereed journal” doesn’t mean it’s good science or even scientific at all. In fact, much of what gets published as “science” is twaddle and dreck.

      This pretty much says it all . . .

      From Reason Magazine:

      “So Lewinski plays an active role in convincing officers they are always in danger when dealing with members of the public. Then when one of these shootings happen, he turns around and helps justify these shootings to juries because the officer was afraid he was in danger.

      Lewinski has infuriated researchers by using the concept of “inattentional blindness”—where focus on one task blocks out everything else—to justify police mistakes. Such an argument, one prosecutor noted, could be used to justify any police shooting, no matter the circumstances. But just imagine if a non-police citizen tried using the argument in a case. Would it end up like this one?”

      • See: Sokal affair

        Looks like the mail-order doctor’s latest “contribution” is that since memory under stress is questionable, one cannot fault cops when they simply make shit up after murdering someone, i.e. an anti-perjury get-out-of-jail-free card.

        I wonder if he’ll call for mandatory body cameras, as well as criminal punishment for tampering with said cameras. 🙂

  1. A hundred people witness the same event and you’re going to get 167 different versions of what happened. Every one the gospel.

    Rushing to judgement before a thorough investigation is done is never good. I for one would not want to be a judge, juror or investigator in a serious event. Trying to get the absolute truth is probably just not possible.

  2. And Robert continues to call us Civilians instead of Citizens. Last time I checked the Police in this Country were a Civilian Police force.

    • But Warrior Cops brother. Camo and an old Brinks truck just like the SEALS use brother.

      OK that’s more Sheriff’s who shouldn’t have any control over discretionary spending but still. Militarize and create an “us vs them” attitude and pretty soon we’ll end up exactly where we are now.

  3. Cameras burned onto officers corneas, it’s the only reasonable answer. No anesthetic allowed to weed out the weak and those lacking dedication.

  4. In the news crew shooting last week, the survivor’s husband states his wife told him she heard the trigger being pulled going click a few times after she was shot and my guess he was out of ammo. Glocks don’t have DA / second strike triggers, if he had reloaded then the Glock would have went BANG, doubt if he had that many bad rounds in the second mag. She had just heard 15-16 rounds go off within feet without hearing protection but was able to hear the trigger being pulled. Sorry but I seriously doubt if her hearing was not affected by those gunshots to the point her ears were ringing.

    High stress causes all of us to focus on the threat or task at hand, we tune out what we perceive to be non important actions.

  5. I give this a solid “maybe.” Here’s why: some people suck at estimating distance. Some people suck at estimating time. Others aren’t good with detail. I’ve met many people who are playing an unfortunate catch up game with the speed of life. Police officers are supposed to be good at those things. That isn’t always the case. Add stress and those skills degrade even further.

    Someone who’s good at estimating 21 feet will still likely be good under stress. Ditto for shooting. Use a shot timer regularly? You’ll probably be much better than average at estimating time. And there’s the 80 year grandma who still shoots well under stress with just about zero training. That grandma might describe her violent with exceptional detail.

    I’ve spoken with some witnesses who are flat out rock stars at accurately describing suspects and stressful crime situations. Their accounts were very similar to video. Others witnesses are borderline retarded. They give stuttering statements that have little investigative value.

    In a criminal investigation, including a shooting or stabbing, eyewitness accounts are typically the least reliable evidence. One must always factor in all available evidence and the totality of the circumstances.

  6. Under major stress in any situation, people will lose time line and facts. My 88 years old grand mother had a massive heart attack and I performed CPR on her while my parents were acting like chicken with no heads. Although they think they do, my parents do not factually remember the entire sequence of events: when I arrived, what the 911 operator said, when my brother entered the room, what they themselves exactly where doing, how long before the EMT arrived, etc…. fascinating experience. To conclude: never talk to the police without a lawyer, even if you have done nothing wrong. You may think that you remember precisely what happened, but may be you don’t. [Grand mother ended up surviving, god bless her]

  7. STFU still applies. They might be frustrated or even suspicious of your demeanor but at least you won’t help them close the case with you inside it.

  8. Repeat after me (albeit while babbling incoherently): “Why didn’t he stop? Why didn’t he stop? (sob, sniffle, sob)……. I think I wanna talk to a lawyer”

  9. Instead of body cams, why not pistol cams? Something that sits where a light would sit, maybe include a light and laser. At least you’d get footage of anything the gun was pointed at. Of course you wouldn’t get footage of any beatings that did not involve a drawn gun.

    Hmm. Random thoughts on a tangential subject.

  10. Thank you for coming to see me officer. I was in fear for my life, for imminent danger of the bad guy who was attacking me a weapon with deadly force- I had no choice but to shoot to stop him. This is his description ( ht, wt, hair eyes, clothes).

    Oh, do you see that guy, and that guy and that guy – they are witnesses who I think saw the whole thing- they can fill you in on more.

    Now, if you dont mind, I am feeling faint, my heart condition I think- can I get a ride in the ambulance now, please? I will be glad to talk to officers more later. I need to lay down…ohhhh! I am feeling faint!

    (in the ambulance, call your attorney and get him to the hospital. Until he arrives, STFU!)

    • I think that’s a great idea. Fake medical distress, there’s no way either the EMTs or hospital can tell you are not in medical distress. All those machines and tests they do, so easy for a person to make them display accurate medical distress indicators. Plus we all know that faking medical distress would never, ever be used by a DA to discredit your whole story and make you out to be liar in front of a grand jury.

      • I meant to add that your “excited utterance” in front of the EMT while talking to your attorney may bite you in the butt. The EMT may testify in front of the grand jury that after complaining of medical distress, you carried on a lucid and intelligent conversation with your attorney. He/she further testifies that you had no symptoms of medical distress other than the expected elevated stress levels. Don’t play weak/meek with the cops when you are not a weak/meek person in real life, just STFU! Don’t put on an act, just STFU!

  11. Questioning the messenger’s credentials does not alter the fact that high stress events alter or delete memory. That’s been proven long before the Force Science Institute put together their stable of “hired gun” expert court witnesses.

    What the jury believes (or not) is an entire other subject, reinforcing the wise advice it’s absolutely vital to keep your mouth shut following the unholstering of your weapon, whether it’s been fired or not.

    • Rick, Yes – my comment was an ad hominem attack on Dr. Lewinski and his authenticity. I encounter more than a few that go far beyond just resume burnishing. Lewinski seems like the epitome of a particular brand of fraudster that breeds mistrust in justice and science.

      Am aware of some studies on false memories, inaccurate recollection, and bias before reading the TTAG Force Science Institute piece. There are techniques to hone one’s recollection accuracy. Here’s one

      I was challenged by cops during a ride-along to recall vehicle descriptions, plate numbers, and other details – was amazed at their skills. They were having fun with me and showing off, but BOLO skills can be acquitted.

      Would these recollection skills work in adrenaline-fuled encounters? Don’t know.

      • The recollection of events where you are an only observer, and not a participant, lack the amount of stress and adrenaline dump necessary to play serious havoc with memory.

        Thirty-four years ago I piloted a little airplane onto a small patch of ice on a river’s edge after the engine shuddered, then summarily quit. Certainly a life-threatening event creating physiological changes approaching that which would occur during a gunfight.

        Then and now I vividly remember the entire event EXCEPT for maybe 5 to 7 seconds starting just moments before touchdown, and the initial rollout immediately following (when death could have occurred had it gone bad). Had the tunnel vision, and the slow motion occurring …. but the missing 5 to 7 seconds was either never entered into memory, or instantly erased. Like it never happened.

        I have no doubt that life-threatening stress plays havoc with the mind and accurate recollection. In my case, there’s nothing registered there to remember.

  12. Between the cops poor recall, terrible eyewitness accounts and questionable “informants” it’s amazing warrants are ever issued. Unless of course judges are inept.
    A system of checks and balances where all the participants are dumb, ignorant or junkies. That’s healthy.

  13. I find it best to rehearse and what you would say, much like you rehearse what you would do if you had to draw your gun…

    Not to have a rehearsed story, but for the same reason you rehearse with your gun, aka, practice, train, etc…

    Rehearsing the words AND the actions assure that if that moment comes to find you, you have that much more of a solid and APPROPRIATE action. The words you rehearsed will be your actions. Congruency. Reinforcement.

    And then, when you do talk, it’ll be exactly the truth, and exactly legal. Even though you know you’re not supposed to talk, you will, at least a little. After having that traumatic experience, you’re going to talk even when you know you shouldn’t, even when you know they’re going to try to frame you any way they can…

  14. best to remain silent, and be thought a fool.

    put a gun rights defense attorney on your speed dial, and hope the cops don’t take your phone before you make the call.


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