Three police officers wore clunky bracelets that in shape, weight and size resemble house-arrest ankle monitors for six weeks as part of an RTI International study monitoring their stress levels throughout the day.
“It's like a Fitbit on steroids,” said RTI senior public health researcher Robert Furberg who co-authored the study.
“This is what gets me excited,” Furberg said. “Can we gather information about people with them being aware of it but without asking them to do very much? Can we gather information over a long period of time? And use it, measuring changes in their health statuses or drive us to produce some sort of interventions.”
RTI partnered with the Durham Police Department to better understand police officer stress levels because high stress levels can affect decision making. In a profession that requires snap judgment calls and quick decisions, with corresponding actions which may or may not mean the difference between life and death, understanding stress, is — needless to say — important.
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The study, a “Biometrics & Policing pilot,” was published in the journal JMIR Research Protocols under the title: “Biometrics and Policing: A protocol for multichannel sensor data collection and exploratory analysis of contextualized psychophysiological response during law enforcement operations.”
The study is the first of its kind, Furberg said. It was published last week.
“The literature that's out there and the studies that people have done about officer stress, which we think has a lot to do with officer performance, has been limited to self-report,” Furberg said. “Researchers would have to go to officers and say, “Hey, were you freaked out on that call? Just now? Or even worse, 'Hey, were you freaked last week, when you had that call, tell me how you felt?'”
The study's aim was to take a more objective approach to studying stress. To move from qualitative assessment of stress— “How do you feel?” — to a quantitative approach, assigning hardline, indisputable physiological-response data to states of stress.
The study gave feelings calculable numbers.
There are two types of commonly referred to veins of stress -- acute and chronic.
Acute stress gets humans excited and is absolutely appropriate in policing, Furberg said, and in many cases actually protects officers.
“And there is this notion of chronic stress which is more in line with the baggage that an officer has to deal with when they leave their job: household, family, financial or other emotional stresses,” Furberg said. “But if people are exposed to acute stress over and over and over again, can alter and make peoples' decision making worse. When we think about putting someone who is really stressed out in a stressful situation, around the use of force, this is where we start seeing the value of this new type of objective measurement.”
Bodily responses to emotional states have been studied since the late 19th century and modern researchers have found that when a person is stressed their skins' resistance to electrical conductivity decreases.
Three Durham police officers wore devices — the Empatica E4, made by Empatica Inc. — that monitored their stress levels via signals captured by the devices' senors, including skin temperature, heart rate, movement and electrodermal activity.
The study's participants were one African-American male officer, one Latino male officer and one white female officer.
One of the officers responded to a suicide while wearing the device and researchers found that the officer’s stress levels were at their highest when they had to tell the deceased's family about the death.
Furberg has applied to National Institute of Justice grant that would expand a follow-up study to 25 to 100 participants.