A study conducted by researchers at Seattle University and published this week in open-access journal PLOS One says that a link may exist between officers killed in the line of duty and people of color killed by police the same day.
Drawing on two year's worth of data on slain police (taken from the Officer Down memorial page) and deadly force (taken from a Washington Post database tracking these deaths), researchers found " evidence of a retaliatory, violent relationship between law enforcement and citizens." The change wasn't big, but still statistically significant: Through modeling, SU researchers found a link between a sharp increase in the number of police officers killed in the line of duty to a small increase in the number of people of color killed by police the same day. Under the same scenario, researchers also found a small decrease in the number of white people killed by police.
"In practical terms, if the number of law enforcement officers killed in one day doubles from the average, there are an additional 0.8 minorities shot to death for one day," authors wrote.
But in reverse, the study's authors found the opposite: That upticks in deadly police shootings of non-whites are linked to a decrease in police killed on duty. And when there are sudden increases of white people killed by police, more law enforcement officers are killed.
The authors didn't look at local police deaths and local police violence. Instead, corresponding author Matt Hickman said, they took a macro approach to the research question. National law enforcement organizations often send out alerts about officer deaths across the country to police, and higher ups in police departments sometimes also share that information with subordinates on the job.
The study's authors didn't test for a mechanism that explains these outcomes, but they did offer some theories as to why. One is "terror management theory," a psychological theory first posited in the early '70s that suggests when people are reminded of their own mortality, or primed for death, they react more positively to people with their own worldviews, and negatively to people considered as part of an "outgroup." Terror management theory researchers also suggest that when primed for death, people with decision-making power deal out harsher punishments. In one study testing this idea, a group of municipal judges in Arizona who were reminded of the thought of their own death set higher bonds for arrestees than a group of judges who weren't prompted with the same thought.
To test this idea with law enforcement officers, Hickman suggested that researchers might conduct "primed for death" experiments with police trainees. Does a group of Seattle trainees exposed to news of a police officer's death in, say, Miami, impact their use of force in training scenarios?
Hickman and his co-authors also looked at whether social media might have an impact on how news like this is spread, and they found that it acted like a "contagion." Increases in Black Lives Matter-related tweets (the authors didn't look at whether these tweets were pro or anti-BLM) were linked to a small increase in violence on both sides. To Hickman, this suggests something that has become clear to many people who have chosen to quit the platform for good: that Twitter has real-world impacts, too.