New Washington State University Study: Even Tired Cops Are More Hesitant To Shoot Black Suspects

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The most explosive crisis law enforcement faces today is the allegation that rampant racial bias drives officers’ shooting decisions.

Yet a new study concludes that officers tend not to be biased against black suspects in resorting to deadly force, even when fatigued and thus potentially more vulnerable to making angry, irrational, and impulsive decisions.

Indeed, tired cops and rested officers alike are more hesitant to shoot black suspects than to shoot white ones in similar circumstances and to show better judgment in their shooting decisions when black suspects are involved.

“[T]oday’s police officers tend to be operating in a state of heightened awareness of the consequences of shooting a member of a historically oppressed minority group,” the study notes, and their extra caution regarding black suspects is not overridden even by the potentially debilitating effects of fatigue.

Lead author of the study is Dr. Lois James. She and her research associates, Dr. Stephen James and Dr. Bryan Vila, are connected with the Sleep and Performance Research Center at Washington State University in Spokane. A full report on the current study, titled “Does the ‘Reverse Racism Effect’ Withstand the Test of Police Officer Fatigue?,” has been accepted for publication in the peer-reviewed journal Policing: An International Journal of Police Strategies & Management. At this writing, the date of publication is pending.


In an earlier study led by Lois James [see Force Science News #266 in the newsletter archives at www.forcescience.org], scientific testing of a sampling of white officers revealed that overall they “hesitated significantly longer before shooting armed suspects who were black, compared to armed subjects who were white or Hispanic.” Also they were 25 times less likely to erroneously shoot unarmed black subjects than they were unarmed white subjects.

In contrast to activists’ vociferous claims, James reported that the research found that officer participants “even when they had strong implicit biases against black suspects were more hesitant when faced with black suspects in a simulator.” This hesitancy has been referred to as “counter bias” or the “reverse racism effect.”

Still, in light of the well-documented negative effects of fatigue on LEOs’ performance in other realms, James wondered if the hesitancy to shoot black suspects would vanish if involved officers were tired when their shooting decisions were made.

In other words, if an encounter occurred when an officer was dragging from a long shift, a crushing workload, or chronic sleep deprivation–surely a realistic possibility–would he or she still be “more hesitant to shoot black suspects compared to white suspects” and still be less likely to draw a deadly “mistake-of-fact” conclusion where black suspects were involved?

James guessed not. “[T]he parts of the brain responsible for executive functions such as moral decision making and impulse control tend to be affected the quickest by fatigue,” she explains.

So specifically, she hypothesized that officers would be “significantly quicker to shoot armed suspects” and “significantly more likely to mistakenly shoot unarmed suspects” when fatigued than when rested. And she expected the racial difference favoring black suspects to disappear when officers were tired; in effect, heightening the danger to black individuals.


To test these speculations, James’s team subjected 80 sworn officers–overwhelmingly male whites, averaging over 14 years on patrol–to identical experimental procedures.

Armed with a modified Glock 22, each officer faced a series of “highly realistic” shoot/don’t shoot video scenarios in a “state-of-the-art” training simulator on four separate occasions: twice when considered fatigued (immediately after their fifth consecutive shift of more than 10 hrs.) and twice when rested (72 hours after completing their work week).

On each test day, they experienced six randomized scenarios, featuring a roughly equal number of white or black suspects, armed or unarmed, in “the most common situations in which officer-involved shootings occur.” These included domestic disturbances, vehicle stops, armed robberies in progress, and suspicious persons/circumstances.

In all, “the officers completed a total of 1,517 scenarios,” James says. Their shooting reactions, from the moment a suspect’s weapon became apparent on screen, could be measured in milliseconds.


To James’s surprise, she told Force Science News, “My hypotheses weren’t supported” by the results. Instead, “Officers’ counter bias remained strong, even under conditions of fatigue.”

  • Officers were “marginally” (although “not significantly”) quicker to shoot when fatigued than when rested–but on average they still took fractions of a second longer before deciding to shoot armed black suspects than armed white suspects.
  • As to mistake-of-fact shootings, “the officers were more likely to shoot unarmed white suspects than unarmed black suspects in both fatigued and rested conditions,” James writes. Rested, “officers collectively shot 31 unarmed white suspects (3.6% of the total) and 2 unarmed black suspects (0.3%).” In the fatigued condition, they inexplicably showed an improvement in judgment, collectively shooting “23 unarmed white suspects (2.8%) and 0 unarmed black suspects (0.0%)”
  • “No significant differences [in results] were observed [as to] participant gender and race,” the researchers report. “The key indication of the findings,” James writes, “is that both officers’ decisions to shoot and their tendency to be more hesitant to shoot black suspects than white suspects appeared to be unaffected by officer fatigue.”


Potential explanations of the findings include the possibility that an arousing “adrenalin surge” during the simulator scenarios “temporarily overwhelmed the effects of fatigue” on the officers’ performance, James suggests.

Also, she concedes that she may not have tested them “under extreme enough conditions of fatigue to see a degradation of the counter bias effect.” Plus, the experiments were conducted “in an artificial, laboratory environment,” not on the street.

Further research is needed, she says, including an exploration of whether, in the real world, pre-shooting behavior of officers may be affected by fatigue to the extent that it escalates encounters. “For example,” she writes, “[are] officers more rude or aggressive to black suspects than white suspects, and if so, [is] this difference amplified when they [are] fatigued?”

Such research, she says, could have practical application for agencies, allowing, for example, the analysis and “scoring” of officer behavior recorded by body cams. “This could improve our ability to better hold police accountable for what happens throughout an encounter, as opposed to just its outcome,” James notes.

[Dr. James can be reached at: lois_james@wsu.edu. Our thanks to Force Science instructor Chris Lawrence for alerting us to this study.]

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