Force Science News #156:

Rest and memory: New findings support delaying interviews after an OIS + K-9 scenarios make their training-simulator debut

Editor’s note: What’s it really like to take a Force Science Certification Course? Read a new Law Officer magazine article by recent grad Laura Scarry for a first-hand look at the experience from a student’s perspective. To read the article visit and look for the article titled “Setting the Bar.”


In this issue:


I. Rest and memory: New findings support delaying interviews after an OIS


II. K-9 scenarios make their training-simulator debut


III. Where to go for more information on other important topics


I. Rest and memory: New findings support delaying interviews after an OIS


There’s now more evidence that waiting “a day or 2” after a shooting before interviewing an involved officer will likely produce more accurate and complete recall than insisting on immediate questioning.


That conclusion is reported by Dr. Ed Geiselman, a UCLA psychology professor and a faculty member for the Force Science Analysis certification course, after assessing the findings from a series of experiments about memory.


“It’s generally presumed that memory is best mined when it is freshest,” Geiselman told Force Science News recently, “and before it can be ‘contaminated’ by input from other sources, rationalization, mood change, change of setting, and the normal deterioration over time.”


But Geiselman decided to re-examine this premise after Dr. Bill Lewinski, executive director of the Force Science Institute, mentioned to him that when a department insists on formally interviewing an involved officer before releasing him or her after a shooting, the officer sometimes has been awake for 24 to 36 hours or more when questioned.


Geiselman dug back into data he’d collected several years ago during 3 research projects involving some 600 eyewitnesses. In these experiments, civilians were unexpectedly exposed to what they thought was an authentic, sudden assault involving live actors (the incident was actually staged) or they variously viewed videotape of a real or simulated robbery or purse snatching.


Later the subjects’ abilities to verbally describe participants, identify them from photo lineups, and to recount as much as they could of the action from start to finish (“free recall”) were tested.


Just before the tests, the subjects completed a detailed questionnaire. One of its “many items” was: “How well rested are you right now?” They were asked to rate themselves on a scale of 1 to 5, from “not at all rested” to “very well rested.”


It was these answers, which he previously had not considered in isolation and had not reported, that Geiselman now focused on as he re-analyzed the data.


“I found a very strong correlation between rest and memory,” he says. “In each test, the people who reported being well rested did significantly better than those who weren’t. Their verbal descriptions were more detailed and more accurate, their lineup IDs were more reliable, and their narratives of the action they had witnessed were far more thorough and correct.”


And these were results just from relatively low-stressed, passive observers. “You would expect police officers who’ve been physically and emotionally involved in a high-stress, life-threatening encounter to experience an even more pronounced effect on their memory from fatigue or rest,” Geiselman says.


“Clearly the findings are consistent with the idea that allowing an officer to rest before being interviewed is an important consideration. Rest likely plays a causal role in how well you are able to remember.”


Other researchers have found an additional negative connection between lack of rest and damaged memory. “Recent research suggests that sleep deprivation may contribute to the generation of false memories,” Geiselman notes in an article on his findings that appears in the current edition (vol. 28, issue 2, 2010) of the American Journal of Forensic Psychology.


“We’re not talking about deliberate lies,” he says, “but about involuntary distortions caused by biochemical reactions in the brain to sleep loss that cause you to remember things differently than what really happened. In short—more sleep deprivation, more errors.”


Considering all factors, “waiting a day or 2 for an officer to be better rested before being interviewed extensively about a shooting should not be problematic,” Geiselman suggests. “Any lost memory during that time period should be recoverable because the officer will be in better condition emotionally, physiologically, and cognitively to participate.”


It is believed that deep sleep “plays an important role in the consolidation of memories,” thereby making recall “more complete,” Geiselman writes. “The brain does a lot of work while you are sleeping.”


Lewinski, among others, has recommended that officers be allowed 2 sleep cycles—perhaps even longer in some cases—before having to write a formal statement or submit to an interview about any life-threatening event.


“If an officer is tired, his ability to extract memory is impaired, while the quality of memory is enhanced by sleep,” he explains. “Rest not only helps an officer respond better, providing more information more accurately, but also helps him be more in tune with the interview. He can better avoid distractions and better understand what is being asked and what his answers should be to be relevant and comprehensive.


“Rest also, of course, allows for some emotional decompression. The stress of the incident has some time to fade before the officer has to relive that stress in the interview.”


The challenge, Lewinski and Geiselman agree, may be in getting sufficient rest even when given waiting time to do so. OIS researcher Dr. David Klinger, himself an ex-cop, has pointed out that 46% of officers involved in shootings experience difficulty sleeping within the first 24 hours afterwards. For about one-third, sleep problems persist even after 1 week.


Even if some fatigue remains, Geiselman says, recall will be maximized if officers are questioned by investigators employing cognitive interviewing techniques. This “highly recommended” approach, Geiselman explains, incorporates methods “for reconstructing and reinstating the sensory and emotional context that existed at the time” of the shooting and for “enhancing memory retrieval following some forgetting.”


Cognitive interviewing also has been “found to circumvent certain post-event, contaminating influences,” thereby helping to “counter any negative effects on memory caused by delay,” he says.


In the future, Geiselman hopes to launch experiments that concentrate specifically on rest and memory. “We need to systematically manipulate the length and nature of rest after a critical incident and see how recall is affected. Then we should be able to pinpoint more precisely what level of rest seems most productive.


“Meanwhile, the expression ‘let me sleep on it’ appears to have validity as it applies to memory recall performance.”


For a copy of Dr. Geiselman’s report, “Rest and Eyewitness Memory Recall,” from the American Journal of Forensic Psychology, email him at: His book, Memory-Enhancing Techniques for Investigative Interviewing: The Cognitive Interview, co-authored with Dr. Ron Fisher, is available through


II. K-9 scenarios make their training-simulator debut


A new take on use-of-force judgment training has been developed by the Phoenix Police Dept. in collaboration with simulator manufacturer Ti Training Corp., a strategic partner of the Force Science Institute.


What the 2 entities have created are believed to be the first interactive simulator scenarios specifically designed to test K-9 handlers in decision-making relative to their primary force option, the police dog.


A series of 11 different scenarios, appropriate for testing dog-handler applicants and in-service personnel, will be debuted at the National Police Canine Assn.’s annual training seminar, to be hosted by Phoenix police Oct. 4-8.


The project began last winter after representatives of the department’s dozen or so K-9 handlers expressed a need for testing and training scenarios to Ofcr. Richard Brethour, the agency’s simulator coordinator and the member of the Firearms Training Detail who’s in charge of video production.


Brethour and other trainers filmed 2 scenarios for screening handler applicants, capable of being used on the department’s 3 Ti Training Lab use-of-force simulators.


“In one,” Brethour recently told Force Science News, “the officer being tested faces a situation in which a dog is ‘on bite’ with a suspect who begins firing a gun at the officer. In order to shoot the assailant in the torso, the officer must shoot through the dog.”


Some applicants attempted a head shot, but the majority made what Phoenix trainers consider the right decision, sacrificing the dog to down the suspect. “A K-9 is a tool,” Brethour says. “We prefer not to send a dog on a suicide mission, but in some unfortunate cases a K-9 must be considered expendable. This scenario tests whether the handler applicant has thought about the job in a realistic way.”


For the second initial scenario, the test subject holds on to a bungee cord hooked to a fixed object on the floor, simulating a dog “on lead.” The scenario first takes the officer on a search of an enclosed area. A suspect is flushed out but won’t obey commands. As a capture team tries to grab him, he assaults an officer and takes off. If the test subject releases the bungee cord, as if releasing his dog, a K-9 appears on screen and chases and bites the suspect.


Immediately after the scenario ends, the test officer is instructed to write a bite report, justifying whatever decision he made regarding releasing the dog. “Because an officer has been assaulted, we consider a release to be more desirable,” Brethour explains. “But either way, it’s important to see how the officer articulates his decision.”


After hearing of the department’s efforts with these scenarios, Ti Training, based in Golden, CO, last spring offered to send a professional crew with state-of-the-art cameras and editing gear to film additional scenarios for Phoenix, with the understanding that these could also be made available to the company’s other law enforcement customers. The series that will be shown at the conference resulted.


“We wanted high-speed, complex scenarios that would explore mind-set and generate discussion,” says K-9 Sgt. Rich Maiocco. “At the conference, different agencies mayhave different deployment strategies, and these scenarios will open up fresh ideas on how dogs should be handled.”


Some of the scenarios, which run from 20 seconds to about a minute apiece, relate to deadly force decision-making. “Most,” says Brethour, “center on when to deploy the dog in a wide variety of situations, including threatened suicides and confrontations involving less-lethal weapons. Was the dog properly deployed and can you justify the decision?”


“Deployment judgment is very important to test and reinforce,” says Ti VP Todd Brown, a well-known innovator in the use of simulation training systems for law enforcement and a member of the technical advisory board for the Force Science Institute. “If a dog is released too soon, you have a potential liability issue. If the release is too late, you may miss an apprehension opportunity.


“With these scenarios, you can get into situations that officers normally don’t think about and force them to make decisions under realistic stress situations. They can also be used to teach regular patrol officers about some of the subtleties of K-9 operations, so that everyone gets a better understanding of the job.”


[For more information, Todd Brown can be contacted at Ofcr. Brethour can be reached at: For information on the upcoming conference, contact Sgt. Maiocco at or at 602-509-1741.]



III. For more information on other important topics…


• In our last transmission [#155, sent 7/30/10], we reported on officer fatigue during physical confrontations. Since then, Wayne Schmidt, executive director of Americans for Effective Law Enforcement (AELE), has brought to our attention that the IACP has published a Training Key on the general subject of fatigue among LEOs. This report, which contains suggestions on how to obtain quality sleep despite the demands of a law enforcement career, can be ordered from the IACP by clicking here.


• And don’t forget AELE’s upcoming 3-day training program on Lethal and Less-Lethal Force, Oct. 11-13 in Las Vegas. This unique seminar will explore the latest findings on the legal, psychological, and physiological aspects of officer-involved shootings and other significant uses of force. Several members of the faculty are certified Force Science Analysts. For a fully descriptive brochure and registration information, click here or visit


• Also of interest are guidelines regarding subjects who have been Tasered, published by the American Academy of Emergency Medicine. This advisory is directed to emergency room physicians and other medical personnel to help them properly examine and evaluate patients who have experienced a conducted Energy Weapon “ride.” The guidelines can be accessed freeof charge by clicking here or visiting

Thanks to Mike Williams, deputy chief of the Chattanooga (TN) PD for bringing this to our attention.


Written by Force Science Institute

August 13th, 2010 at 10:24 am

© 2017 Force Science Institute Ltd.