Chris Butler, Advanced Specialist and Senior Force Science Instructor
(Editor’s note: The following commentary was originally posted by Chris Butler, Insp. (Retired) on social media and later adapted for publication in Force Science News.)
As researchers explore the relationship between physiological arousal and police performance, trainers continue to question whether heart rate was ever a valid predictor of such performance. Early in our careers, many of us were taught that elevated heart rates equaled decreased performance; but my studies of reality-based training never convinced me of that.
Now, a 2019 report, published in Frontiers in Psychology, adds to the growing list of research confirming that heart rate is not a reliable predictor of officer performance…well sort of.
In Differential Effects of Physiological Arousal Following Acute Stress on Police Officer Performance in a Simulated Critical Incident1, researchers examined the effects of physiological arousal on officers’ verbal communication, nonverbal communication, and tactical skill.
In the study, officers volunteered to respond to a complex training scenario which, unknown to them, would evolve into a “lethal force” encounter. Participants’ arousal levels were captured by measuring maximum heart rate during the training incident, as well as pre- and post-scenario levels of Cortisol (hormone released in response to stress) and Antithrombin (natural blood thinner shown to elevate after stressful psychological tasks).
Researchers expected to find that greater stress response (including increased heart rate) would predict better tactical skill—but that verbal and nonverbal communication scores would suffer.
Instead, researchers found that indicators of greater physiological arousal did not significantly affect nonverbal communication or tactical skills. However, increased heart rates were associated with lower verbal communication skill; a finding that was consistent with similar studies identified in the report.
So, is heart rate a reliable predictor of officer performance? Not for tactical performance, where well rehearsed skills survive increased heart rates. But where officer “performance” includes the ability to effectively communicate before, during, and after critical incidents—heart rates may still matter.
Trainers, especially those who design and conduct reality-based training, are encouraged to read the full report, which is extensively footnoted with survival stress response and human performance studies.
And, while high stress can negatively impact verbal communication, there is promising evidence that training tactical skills until they become automatic, increases confidence, relieves the attentional system, and results in reduced arousal states during critical incidents. This overall reduction in cognitive load and arousal may provide the physiological conditions necessary for improved verbal performance.
Readers can access the original research article here.
1 Arble E, Daugherty AM and Arnetz B (2019) Differential Effects of Physiological Arousal Following Acute Stress on Police Officer Performance in a Simulated Critical Incident. Front. Psychol. 10:759. doi: 10.3389/fpsyg.2019.00759