Unique New Study Confirms Memory Discrepancies After OISs

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New research findings by the Force Science Institute provide fresh evidence that an officer’s ability to accurately remember potentially important details may be significantly compromised after a shooting.

“In certain circumstances, these findings may help investigators account for memory discrepancies that might otherwise be interpreted as an officer’s willful effort to be misleading,” FSI’s executive director Dr. Bill Lewinski told Force Science News. “This research adds a small but important piece to the growing scientific mosaic of how the human brain reacts to highly stressful, life-threatening events.”

The findings have emerged as researchers continue to mine a rich lode of data gathered during a ground-breaking FSI experiment in which LEO volunteers were unexpectedly attacked with Simunition rounds fired by an angry driver during a traffic stop scenario.

Initially, the research team analyzed the subjects’ immediate physical responses in an effort to determine what path of movement would most quickly bring the officers to a safe location. [Those findings were reported in FSN transmitted 2/25/13. Click here to read it. See also the detailed report titled “The Influence of Officer Positioning on Movement During a Threatening Traffic-Stop Scenario,” which appeared in the journal Law Enforcement Executive Forum and is posted on the Force Science website. You can read it by clicking here.]

Now the team, headed by Lewinski, has studied a subset of the volunteers to see how accurately they were able to remember the precise route they took in their flight to escape the gunfire–one of many details officers may be asked to accurately report on after an OIS.

“Focusing on that level of detail may seem trivial,” Lewinski observes, “but in real life it has proved vital for some shooting survivors.” In the Force Science certification course, for example, Lewinski recreates the case involving Arizona officer Dan Lovelace, who was charged with murder after a fatal shooting, in part because he misstated where he moved in an effort to dodge a vehicle that was being driven directly at him.

“There was merely six inches of difference between where Officer Lovelace said he moved and where forensic evidence calculated that he actually moved, but it was enough to raise doubt about his credibility and to help wreck his law enforcement career and his life,” Lewinski says.


The unique memory component of the traffic stop study involved 24 of the participating officers, sergeants, and detectives–all randomly selected males, ranging in age from 27 to 54, with up to 31 years on the job.

Promptly after they had been “intensely stressed” by being fired on (as confirmed by physiological monitors), each was given a sheet of paper with a diagram of the shooting scene, including the positioning of their patrol car and the suspect vehicle.

During the scenario, most had fled to the rear of the gunman’s car in an attempt to escape. Based on their memory of what had just occurred, they were instructed to draw “as accurately as possible” their path of travel from the instant the assailant drew his weapon until they heard the whistle that ended the scenario. They were allowed “as much time as necessary” to complete the drawing.

Later, the research team made meticulous, frame-by-frame computerized analyses, comparing the officers’ drawings with digital video recordings of their actual flight paths from danger.


Here’s what they found:
  1. the officers tended to recall and draw a much tighter curve of travel around the rear of the offender’s vehicle than they actually made as they ran to their eventual stopping point, and
  2. they thought they ran a significantly longer distance than they actually did.

The fact that memory errors occurred was not surprising to the researchers, based on well-documented studies of brain function under stress. “In a life-or-death confrontation,” Lewinski explains, “the brain automatically filters out what it believes to be irrelevant in its laser focus on what is most important–survival. Later, exact details that were subconsciously judged to be extraneous are likely to be impossible to recall with precise accuracy, because they were not imprinted in a person’s working memory.”


The findings from this first-of-its-kind study “demonstrate the amount of error that investigators can likely anticipate when dealing with recalled movement, distance, and location during a high-stress event, such as an OIS,” Lewinski says.

“The implications of the study are broader than that, however. After a shooting, officers are commonly asked not only to recall where they moved but where they fired their first round, how they held their firearm, how many rounds were fired, and so on. In the midst of a life threat, they are likely to be acting automatically, without conscious thought, and what they can recall or think they can recall about automatic behavior, if anything, may not reflect what really occurred because it was not recorded in conscious memory. Their overwhelming cognitive focus would have been on saving their life.

“The credibility of officers and witnesses is often challenged because of inaccuracies in their recollections of critical incidents. They are expected to be accurate with incredible precision, and their inability to do so is too often equated with deception. We hope that this study will help in redefining the expectations of memory more realistically.”

An academic paper on the study will be submitted to a peer-reviewed journal for publication. We’ll advise when that is available.

Meanwhile, read the article below to see how officers’ recalled estimations can be challenged in real-world situations.

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