Force Science News #210:

Research Roundup: New studies on use of force, ExDS, sleep, & more

I. Survey documents significant police “restraint” in use of deadly force


LEOs use deadly force far less often than they’re legally justified in doing, in contrast to a media-fueled public impression that excessive force by America’s cops is “general and widespread,” according to a recent survey of police/citizen encounters.


While officers kill an average of about 385 subjects a year, this toll, in fact, reflects significant restraint, authors of the study conclude. A “large number of officers,” they report, “have been in multiple situations in which they could have used deadly force, but resolved the incident without doing so and while avoiding serious injury.”


The research team includes two former faculty members of the Force Science Analysis certification course, Dr. Anthony Pinizzotto and Edward Davis. Pinizzotto, a retired FBI senior scientist, and Davis, a retired FBI Academy instructor, previously authored three landmark studies of OISs. They were joined in the current survey by Shannon Bohrer, a retired MD State Police sergeant, and Benjamin Infanti, who holds a master’s degree in forensic psychology.


The four polled nearly 300 LEOs, with an average of 17 years on the job. Collectively, the officers had more than 5,000 years of experience.


• 80% reported that “they had been assaulted at least once during their career” (the average was seven assaults in the line of duty), with 27% injured severely enough to require time off work;


• 96% said they had drawn their firearms “at least once each year…under threatening or critical circumstances”;


• 70% said they had been “involved in at least one situation where they legally could have discharged their firearm.” On average, each had experienced four such situations;


• Yet only 20% had actually fired their weapon in a critical incident.


“Officers in the sample were involved in 1,189 situations where deadly force was a legal course of action,” the researchers note. “Officers used deadly force in 7% of these situations. In other words, [they] used restraint 93% of the time even when not legally mandated to do so. This…represents a significant amount of restraint by police officers.”


The media’s focus on shootings “overshadow[s] the actuality that police officers overwhelmingly employ restraint” and “helps create the misconception that… officers use deadly force more often than they actually do,” the research team reports.


In the future, the study group hopes that research will more deeply explore officers’ “thought processes in the decision to use deadly force or restraint…. For example, what factors [lead] to…officers using restraint? Does the use of deadly force reduce or increase the inclination…to use restraint in subsequent critical incidents? How do individual officers perceive restraint and deadly force? What characteristics of an incident lead to deadly force?…


“[I]t is essential that research analyzes how restraint can safeguard against the excessive use of force. These principles then can be applied to officer training in safety and tactics.”


A fuller account of the restraint survey can be read in the FBI Law Enforcement Bulletin. Click here to read it.




II. 1 in 6 uses of force may involve subjects with excited delirium


A research team led by Force Science faculty member Dr. Christine Hall has brought to light the first reliable statistics in another shadowy and controversial area: the frequency of forceful contact between police and subjects displaying signs of excited delirium syndrome (ExDS).


With five associates, Hall, an emergency medicine specialist and ExDS authority based in British Columbia, analyzed 1,269 consecutive use-of-force events that occurred over a 36-month period during more than 1.5 million police/public contacts in a large Canadian city with nearly 2,000 sworn officers. This study and its ongoing data collection represents the largest database of consecutive general use of force events (including all force modalities) in North America.


In cooperation with the study, officers were instructed to record any evidence of “clinical characteristics” of ExDS that they observed in individuals subjected to use of force beyond “simple escortive techniques.” In other words, as soon as “hard hands” physical and higher levels of force were used, data was collected. Data was collected on all comers not just events with difficult outcome. Officers were given a checklist of “violent behavior, tolerance to pain, constant or near constant physical activity, [unresponsiveness] to police presence, superhuman strength, rapid breathing, [tirelessness] despite heavy physical exertion, naked or inappropriate [clothing] for the environment, sweating profusely, [feeling] hot to the touch, and attraction to or destruction of glass or reflective surfaces.” Officers could check off any number of features, in any combination, or check that “none of the features”. Data collection was contained in normal, in car, use of force reports.


Because it is so common to use-of-force situations apart from any suggestion of ExDS, violence as a “feature of ExDS” was ultimately removed from the researchers’ analysis of ExDS, leaving the 10 remaining features to be assessed.


Nearly 52% of suspects subjected to force displayed none of these flagged behaviors, the study found. But 16.5%—roughly 1 in 6—showed three or more signs of ExDS at the time force was used. The only person who died suddenly in custody during the months surveyed exhibited all 10 ExDS indicators, according to officers’ reports. While this is a small number of people in overall policing across all calls when situations involve use of force, consideration of Excited Delirium becomes much more important.


“It should be noted that not all individuals with large numbers of concomitant clinical signs of ExDS had all the same signs,” the researchers report. In other words, there did not seem to be a single central core group of indicators. Also, with only one death occurring out of the large sample, the team concluded that “we cannot comment on causality or correlation between number of Excited Delirium signs and mortality.”


An important aspect of this study is that giving officers a checklist of features to be aware of does not compel them to find those things present. 83.5% of subjects undergoing use of force had few if any features of ExDS recorded as present at the time force was used. This is important in offsetting the criticism that teaching officers about Excited Delirium causes them to find it in everyone. Hall found that is not the case.


The researchers consider that determining the incidence of ExDS in force encounters is an important step in starting to unravel the mysteries of this rare but perplexing phenomenon. Among other things, they hope that future studies (and the study is ongoing) will illuminate whether higher number of ExDS indicators can predict a suddenly fatal outcome and specifically which symptom or cluster of cues may be associated.


As a byproduct of their principal research, the team confirms that use of force by LE is a relatively infrequent occurrence. Of the 1.5 million police-public face to face interactions that occurred during the study interval, 99.92% did NOT involve a use of force response. This number has been stable across three years of study to date.


A full report of the study appears in the Journal of Forensic and Legal Medicine. Click here to access a free abstract.




III. Snooze you lose? Nope, just the opposite where memory’s concerned


More evidence that sleep improves memory has been logged into research archives.


As part of highly technical research designed to map the connection between various parts of the human brain and memory, British scientists have confirmed findings by other researchers that sleep has a positive effect on retention and recall.


An investigative team led by Dr. P.A. Lewis of the School of Psychological Sciences at England’s University of Manchester exposed two groups of volunteers to a series of photographic images. Immediately afterward, the groups were tested and no significant difference was found between them in ability to recall important details of what they had seen.


One group was tested in the morning and then kept awake for the next 12 hours. The other, tested in the evening, was allowed to sleep through the night.


Subsequent re-testing then revealed that the group that slept remembered more. “[M]emory decays less across an…interval containing sleep than across an equivalent interval of…wakefulness,” the researchers report. In short, sleep appears to reduce the amount of forgetting that takes place, at least short-term.


Scans by the researchers via functional magnetic resonance imaging (fMRI) suggest that the brain’s hippocampus and superior parietal cortex are involved in the role of sleep’s “consolidation” and “stabilization” of “newly encoded memories.”


“This study adds to the growing body of well-documented knowledge that supports letting involved officers rest before taking their statements after a shooting or other high-intensity event,” says Dr. Bill Lewinski, executive director of the Force Science Institute.


“In this study there was no difference between the amount of recall immediately after the exposure to test images and 12 hours later—provided the subjects were able to sleep. Otherwise there was significant deterioration.


“Given that the ability of officers to accurately and fully report on critical incidents is crucial, this study suggests that if we allow officers time for emotional decompression and rest to the point where they are ready for what might be the most important interview of their life and also employ techniques for facilitating recall, such as a walk through, we won’t lose anything in regards to the quantity and quality of information they are able to provide.


“Other more comprehensive studies strongly support the role of memory consolidation through sleep to the point where memory is actually enhanced after sleep.”


A detailed report on the British study appears in the journal Neuropsychologia. You can read an abstract of the findings free of charge by clicking here.


[Our thanks to Cst. Dave Blocksidge of the London Metropolitan Police for alerting us to this study.]




IV. Feeling tired isn’t the only bad result of too few Zzzzzzzzs


Negative evidence about sleep deprivation continues to pile up. Consider these new research findings:


• University of Iowa researchers report that if you’re averaging less than six hours sleep a night, you’re more susceptible to chronic fatigue and high-risk health problems, including obesity, diabetes, and heart disease. Studying 85 male officers from three police agencies in eastern Iowa, they found that working evening or night shifts leaves you 14 times less likely to get restful sleep and more likely to draw back-to-back shifts, worsening your sleep deficit.


The study team urges new approaches to “break the cascade of poor sleep for police officers” in the interest of their personal health and public safety. Among suggestions: change the time of early-morning court appearances for night-shift officers to better assure adequate rest.


An abstract of this study, which appeared in Workplace Health & Safety, can be found by clicking here.


• Shift work has long been known to disrupt circadian rhythm, sleep, and proper work-life balance. Now an analysis of studies by Canadian, Norwegian, and Swedish researchers pinpoints some of the negative specifics.


According to a report in the British Medical Journal, shift work—defined as any schedule other than a regular daytime duty tour—is linked to a 23% increased risk of heart attack, a 24% increased risk of some type of “coronary event,” and a 5% increased risk of stroke.


A 10-person research team analyzed the collective results of 34 studies of the “epidemiology of shift work and vascular events,” involving more than 2,000,000 workers, to reach these conclusions.


In an interview, one of the researchers, associate professor Dan Hackam of Western University in Ontario, noted that shift workers tend to be more prone to sleeping and eating badly. “Night shift workers are up all the time and they don’t have a defined rest period,” he said. “They are in a state of perpetual nervous system activation, which is bad” for various health factors.


Jane White, an occupational safety and health researcher quoted in a BBC News report on the study, recommended “avoiding permanent night shifts, limiting shifts to a maximum of 12 hours, and ensuring a minimum of two full nights’ sleep between day and night shifts” as “simple, practical” means of helping to counteract shift-work effects.


The study can be read in full, without charge, by clicking here.


[Our thanks to Keith Bettinger, formerly with the Suffolk County (NY) PD for sharing this study with us.]


• Two other studies—one from Columbia University, the other from the University of California-Berkeley—report that the brain is more attracted to unhealthy junk foods when sleep-deprived.


Says one of the Columbia researchers, Dr. Marie-Pierre St-Onge, “Under restricted sleep, individuals will find unhealthy foods highly salient and rewarding, which may lead to greater consumption of those foods.” Participants in that study “ate more overall and consumed more fat after a period of sleep restriction compared to regular sleep.”


The lead researcher in the Berkeley study, Dr. Stephanie Greer, a doctoral student in neuroscience, says that sleep loss “significantly impair[s] brain activity in the frontal lobe, a region critical for controlling behavior and making complex choices, such as the selection of food to eat.” Deprived of sleep, the brain seems to fail to “integrate all the different signals that help us normally make wise choices about what we should eat.”



V. Trauma via 911: the forgotten first responders


Dispatchers can be the forgotten first responders when it comes to departmental concerns about the psychological well-being of service personnel. Yet they experience many of the same traumatic reactions to critical incidents and cumulative stress as police officers.


Dr. Michelle Lilly and research associate Heather Pierce of Northern Illinois University have conducted what is believed to be the first published study of on-duty emotional distress experienced by 911 dispatchers. They surveyed 171 dispatchers from 24 states, most of them Caucasian females averaging over 11 years on the job.


Their findings suggest that “one does not need to be physically present during a traumatic event, or to even know the victim of a trauma, in order for the event to cause significant mental health challenges,” Lilly says.


Callers to 911 “are often experiencing an emotional crisis and are hysterical. Telecommunicators are under enormous pressure to control their own emotions while extracting the pertinent information, securing the emergency scene, and communicating with multiple agencies—sometimes during life-and-death situations. Afterward, there’s little time to process what happened” before immediately pressing on with other urgent calls.


Surveyed dispatchers rated their “worst” (most distressing) calls as: unexpected injury or death of a child (16.4%), suicidal callers (12.9%), shootings involving officers and unexpected death of an adult (each 9.9%).


Participants reported “high levels of strong emotions,” including fear, helplessness, and horror in reaction to on-duty interactions. Their exposure to trauma, while indirect, puts dispatchers “at risk for developing symptoms of PTSD,” the researchers concluded.


Pierce cites a “strong need to enhance prevention and intervention efforts” where dispatchers are concerned. Agencies should encourage “discussion among dispatchers about the stresses of the job and how they handle it” and provide intervention services, including allowing dispatchers to participate in debriefings for officers after traumatic occurrences, the researchers recommend.


The full study is published in the Journal of Traumatic Stress and can be accessed for a fee. Click here to go to their download site.



Written by Force Science Institute

August 15th, 2012 at 1:39 pm


© 2017 Force Science Institute Ltd.