Reducing Lethal Force Errors by Modulating Police Physiology

Physiological stress differentially impacts cognitive performance during-and memory following-simulated police encounters with persons experiencing a mental health crisis

Police officers frequently make decisions under stress and require accurate memories of their perceptions and actions for subsequent investigations. Recognizing that police are frequently called to assist people experiencing a mental health crisis, it is of critical importance to public safety to understand the role of stress on officers' cognition when navigating such encounters. Despite this, how the timing of experiencing stress impacts officer cognition is understudied in applied police contexts and therefore remains unclear. To address this gap in the literature, we analyzed data from a study of 57 police officers who wore heart rate monitors to record physiological arousal before, during, and after two reality-based scenarios (i.e., simulated calls for service) with individuals experiencing mental distress. Scenarios were audio-recorded, transcribed, and coded to measure officers' perceptual memory of important elements in each scene, procedural memory to enact best practices, post-incident memory of their own actions, and higher-level situational understanding. We found a nuanced relationship between the timing of stress and cognitive performance, such that higher heart rate before and during scenarios improved understanding, decision making, and the appropriate choice of use of force option, but at the expense of officers' spatial processing. Increased heart rate during the post-incident debrief was associated with the following: making a lethal force error during the scenario, decreased memory for perceptual aspects of the scenario, and impaired recall of one's own actions. Older and more experienced officers exhibited overall lower physiological arousal, and female officers demonstrated better cognitive performance compared to male officers. These results have practical implications in operational, training, evaluation, and testimonial police contexts and can inform future interventions aimed to improve outcomes when navigating stressful encounters, including crisis intervention.

Psychophysiological insights and user perspectives: enhancing police de-escalation skills through full-body VR training

In recent years, Virtual Reality (VR) has emerged as a promising tool for enhancing training responses in high-stress professions, notably among police officers. This study investigates the psychophysiological responses and subjective user experience of active police officers undergoing Mental Health Crisis Response (MHCR) training using an immersive full-body VR system. A total of 10 active police officers with Special Weapons and Tactics (SWAT) training participated in our controlled study. Officers independently took part in one VR training session lasting 7-12 min involving an avatar in crisis portrayed by an actor. Officers wore integrated cardiovascular and electrodermal activity measurement devices for physiological monitoring. VR user experience aspects such as induced symptoms or game mechanics were investigated upon completing the training, aiming to evaluate the officer's perceptions of the technology. We used the DePICT™ scale to evaluate the de-escalation skills of officers, coded by a research professional. Our findings revealed significant differences in heart rate and heart rate variability responses between baseline and VR scenario immersion, suggesting heightened stress regulation during the MHCR simulation using full-body VR. Arousal measurements also revealed measurable responses during the training in VR. Additionally, the user experience assessment indicated a positive reception to the VR training, with minimal VR-induced symptoms. A "Defensive-Dynamics-Dichotomy" was revealed highlighting dominant autonomic responses linked to defensive actions (e.g., officers who drew a weapon; those who kept their weapons holstered) and their respective implications for stress management and cognitive function. A unique constellation of de-escalation skills was revealed among officers who relied on weapons relative to those who did not, to resolve the scenario. The study highlighted the perceived utility of physiological monitoring technologies in enhancing police training outcomes. In conclusion, our research underscores the potential of VR as an effective tool for de-escalation training following MHCR simulated scenarios among active police officers, offering insights into its psychophysiological impact and user experience. The findings contribute to improving our understanding of the physiology associated with decision-making in police officers to draw a weapon, emphasizing the role of advanced simulation and physiological monitoring technology in developing evidence-based training programs for public safety.

The International Performance, Resilience and Efficiency Program Protocol for the Application of HRV Biofeedback in Applied Law Enforcement Settings

Law enforcement officers are routinely exposed to high-threat encounters that elicit physiological stress responses that impact health, performance, and safety. Therefore, self-regulation using evidence-based approaches is a priority in police research and practice. This paper describes a five-module heart rate variability biofeedback (HRVB) protocol that is part of a larger resilience program (the International Performance Resilience and Efficiency Program - iPREP) established in 2014. Supported by 10 years of user-informed research and development, our methods are tailored to address occupational stressors and the practical realities of training and resource availability in operational settings. Building on existing clinical methods that comprise five to six weekly sessions and up to 40-min of daily practice, our iPREP HRVB protocol is typically delivered in a condensed format across 2-3 days and is seamlessly integrated with reality-based training scenarios commonly employed in policing. By combining best practices in clinical HRVB with police-specific pedagogical frameworks, officers receive accelerated and job-relevant training to adaptively modulate autonomic responses to acute and chronic stress. Efficacy of the iPREP HRVB protocol is supported by several research studies of various methodological designs (i.e., randomized control trial, longitudinal cohort) that demonstrate immediate and sustained improvements in police performance and physiological health outcomes. We conclude with a critical appraisal of the available empirical evidence contrasting common and emerging breathing techniques proposed for use in operational policing contexts. The critical appraisal guide is intended to serve as a resource for law enforcement agencies, governing bodies, and operators when choosing appropriate and effective self-regulation training approaches.

The neurobiology of interoception and affect

Scholars have argued for centuries that affective states involve interoception, or representations of the state of the body. Yet, we lack a mechanistic understanding of how signals from the body are transduced, transmitted, compressed, and integrated by the brains of humans to produce affective states. We suggest that to understand how the body contributes to affect, we first need to understand information flow through the nervous system's interoceptive pathways. We outline such a model and discuss how unique anatomical and physiological aspects of interoceptive pathways may give rise to the qualities of affective experiences in general and valence and arousal in particular. We conclude by considering implications and future directions for research on interoception, affect, emotions, and human mental experiences.

Physiological Responses to Organizational Stressors Among Police Managers

Police officers demonstrate increased risk of physical and mental health conditions due to repeated and prolonged exposure to stressful occupational conditions. Occupational stress is broken into two types: operational stress, related to the content of field duties (e.g., physical demands); and organizational stress, related to cultural and structural contexts (e.g., interpersonal relationships). Applied police research focuses on physiological activation in operational tasks as a mechanism explaining health risk and non-optimal performance outcomes. However, recent survey-based studies indicate numerous organizational stressors associated with self-reported mental health symptoms. The question of whether organizational stressors elicit significant physiological activity remains unknown. The current proof-of-concept field study tests the hypothesis that police managers will display significant physiological reactivity before, during, and after engaging in reality-based scenarios representative of stressful police management tasks developed from evidence-based pedagogical approaches. A sample of 25 training police managers (7 female, M = 16 +/- 5.3 years of experience) completed 5 reality-based scenarios, including resolving a heated conflict between colleagues, delivering negative feedback to a subordinate, and critical incident command. Significant increases in heart rate relative to rest were observed during all tasks, and in anticipation of several tasks. Greater increases in reactive heart rate were associated with longer recovery times. Sex differences and relationships between objective biological and subjective psychological measures of stress are discussed. The current findings demonstrate significant physiological responses to organizational stressors similar to levels observed during operational tasks, despite the absence of physical or aerobic exertion. Implications for police health and training are discussed.

Cardiovascular risk, social vigilance, and stress profiles of male law enforcement officers versus civilians

This study examined the cardiovascular disease (CVD) risk profiles of male law enforcement officers (LEOs) and civilians. CVD risk profiles were based on data collected using traditional objective (e.g., resting BP, cholesterol), novel objective (e.g., ambulatory BP) and self-report measures (e.g., EMA social vigilance). A subset of male LEOs (n = 30, M age = 41.47, SD = 8.03) and male civilians (n = 120, M age = 40.73, SD = 13.52) from a larger study were included in analyses. Results indicated LEOs had significantly higher body mass index [BMI], 31.17 kg/m2 versus 28.87 kg/m2, and exhibited significantly higher trait and state social vigilance across multiple measures, whereas perceived stress was higher among civilians. Findings highlight the need for future research examining CVD risk associated with occupational health disparities, including attributes of individuals entering certain professions as well as experiential and environmental demands of the work.

Interoceptive ability moderates the effect of physiological reactivity on social judgment

Social judgments-that others are kind or cruel, well intentioned, or conniving-can ease or disrupt social interactions. And yet a person's internal state can alter these judgments-a phenomenon known as affective realism. We examined the factors that contribute to, and mitigate, affective realism during a stressful interview. Using data collected between 2015 and 2019, we hypothesized and found that individuals' ability (N = 161; 57.6% female; 57.6% European American, 13.6% African American, 13.6% Asian American, 6.4% Latinx, 6.0% biracial, and 2.8% that identified with none or 1 + of the races presented; Mage = 19.20 years) to accurately perceive their own internal sensations (i.e., heartbeats) influenced whether they attributed their own heightened stress reactions (i.e., sympathetic nervous system reactivity) to the behavior of two impassive interviewers. Participants who were poor heartbeat detectors perceived their interviewers as less helpful, polite, or professional, and more apathetic, judgmental, and aggressive when experiencing heightened levels of cardiovascular sympathetic nervous system reactivity during their interview. Being aware of one's internal state may be one pathway to reducing bias in social perceptions in circumstances where such biases may lead us astray. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Not according to plan: Cognitive failures in marksmanship due to effects of expertise, unknown environments, and the likelihood of shooting unintended targets

Shooting errors have multi-faceted causes with contributing factors that include sensorimotor activity and cognitive failures. Empirical investigations often assess mental errors through threat identification, yet other cognitive failures could contribute to poor outcomes. The current study explored several possible sources of cognitive failures unrelated to threat identification with live fire exercises. Experiment 1 examined a national shooting competition to compare marksmanship accuracy, expertise, and planning in the likelihood of hitting no-shoot or unintended targets. Experts demonstrated an inverse speed/accuracy trade-off and fired upon fewer no-shoot targets than lesser skilled shooters, yet overall, greater opportunity to plan produced more no-shoot errors, thereby demonstrating an increase in cognitive errors. Experiment 2 replicated and extended this finding under conditions accounting for target type, location, and number. These findings further dissociate the roles of marksmanship and cognition in shooting errors while suggesting that marksmanship evaluations should be re-designed to better incorporate cognitive variables.

Associations between police lethal force errors, measures of diurnal and reactive cortisol, and mental health

Errors in lethal force by police are met with significant demand for explanations as to why they occur, stimulating a growing body of multidisciplinary research. Acutely stressful occupational conditions result in decrements to police performance, including lethal force decision-making. Further, although it is known that repeated and prolonged exposure to potentially traumatic work-related encounters is linked to higher rates of mental health symptoms, it is unclear if psychological symptoms are related to police performance, and lethal force errors specifically. The present study tested the relationships between biological stress and psychological symptoms on lethal force errors among a combined sample of non-clinical, active-duty frontline (n = 57) and tactical (n = 44) police officers. Specifically, biological measures included: diurnal (cortisol awakening response - CAR), and reactive cortisol (prior to and in response to realistic critical incident (CI) simulations). Psychological self-reported symptoms included: pre-CI stress, depression, anxiety, PTSD, and occupational stress. Tactical officers displayed higher CAR compared to frontline officers, consistent with prior research. When including outliers, CAR significantly predicted lethal force decision-making errors; however, the effect does not remain once removing the influence of outlier CAR observations. The current findings suggest that biological measures of reactive cortisol may be too nonspecific to predict lethal force errors during acutely stressful police operations and measures of diurnal cortisol are heavily influenced by outlier values. Non-clinical levels of psychological symptoms (as measured in this study) do not appear to interfere with lethal force decision-making. It remains to be tested if clinically diagnosed disorders would interfere with police performance. Implications for future applied health research are discussed.

Pulling the Trigger: The Effect of a 5-Minute Slow Diaphragmatic Breathing Intervention on Psychophysiological Stress Responses and Pressurized Pistol Shooting Performance

This study examined the effect of slow diaphragmatic breathing on psychophysiological stress responses and pressurized performance. Sixty-seven participants (40 female; Mage = 20.17 ± 2.77 years) were randomly assigned to either a diaphragmatic-breathing, paced-breathing, or control group. Participants completed a nonpressurized shooting task and then received instructions about a pressurized version. Next, the diaphragmatic group was told to breathe at 6 breaths/min, the paced group at 12 breaths/min, and the control group received no instructions. Following a 5-min intervention period, participants completed the pressurized task while performance was assessed. Psychophysiological stress responses (e.g., cognitive anxiety, heart rate) were recorded throughout. Results revealed that diaphragmatic breathing had mixed effects on stress responses, with some unaffected (e.g., heart rate) and others reduced (e.g., cognitive anxiety), and little effect on performance. Findings suggested that slow diaphragmatic breathing might not aid pressurized performance but could benefit psychological stress responses.

Neurocognitive impairment in night and shift workers: a meta-analysis of observational studies

OBJECTIVE

Shift work is an essential element of modern labour, ensuring ideal conditions of service for today's economy and society. Despite the beneficial properties, its impact on the neurobehavioural performance of exposed subjects remains controversial. This meta-analysis aimed to provide the first summarising effects regarding the association between shift work exposure and different cognitive functions.

METHODS

A literature search was performed using the databases PubMed, PsyINFO, PsyARTICLES, MedLine, PsycNET and Scopus including eligible studies up to April 2021 that compared shift workers with non-shift workers regarding neurobehavioural performance tests. We carried out a random-effects model using Hedges' g as a meta-analytical effect size with a restricted likelihood estimator to summarise the mean differences between the exposure group and controls. Positive effect sizes indicate higher performance for non-shift workers. The heterogeneity of effect sizes was addressed by sensitivity analysis using funnel plots, Egger's tests, p-curve analysis, meta-regressions and subgroup analysis.

RESULTS

We included 18 studies resulting in a total sample of 18 802 participants and 37 effect sizes concerning six different neurobehavioural outcomes. Our results showed significantly worse performance in shift workers compared with non-shift workers in the following cognitive functions with g (95% CI): processing speed 0.16 (0.02 to 0.30), working memory 0.28 (0.51 to 0.50), psychomotor vigilance 0.21 (0.05 to 0.37), cognitive control 0.86 (0.45 to 1.27) and visual attention 0.19 (0.11 to 0.26).

CONCLUSIONS

We provide the first meta-analytical findings that associate shift work with decreased cognitive performance in processing speed, working memory, psychomotor vigilance, cognitive control and visual attention.

Knowledge, Skills, and Abilities for Managing Potentially Volatile Police–Public Interactions: A Narrative Review

We conducted a narrative review of existing literature to identify the knowledge, skills, and abilities (KSAs) necessary for officers who police in democratic societies to successfully manage potentially volatile police–public interactions. This review revealed 10 such KSAs that are frequently discussed in the literature. These KSAs include: (1) knowledge of policies and laws; (2) an understanding of mental health-related issues; (3) an ability to interact effectively with, and show respect for, individuals from diverse community groups; (4) awareness and management of stress effects; (5) communication skills; (6) decision-making and problem-solving skills; (7) perceptual skills; (8) motor skills related to use-of-force; (9) emotion and behavior regulation; and (10) an ability to treat people in a procedurally just manner. Following our review, we conducted semi-structured interviews (N = 7) with researchers who specialize in police training and adult education, interactions with individuals in crisis, and racialized policing, as well as two police trainers with expertise in de-escalation and use-of-force training. These interviews confirmed the importance of the 10 KSAs and highlighted two additional KSAs that are likely to be critical: understanding the role of policing in a free and democratic society and tactical knowledge and skills. To ensure that police–public interactions are managed effectively, police trainers may want to focus on the development and evaluation of these KSAs—something that is not always done currently.

Deep-Breathing Biofeedback Trainability in a Virtual-Reality Action Game: A Single-Case Design Study With Police Trainers

It is widely recognized that police performance may be hindered by psychophysiological state changes during acute stress. To address the need for awareness and control of these physiological changes, police academies in many countries have implemented Heart-Rate Variability (HRV) biofeedback training. Despite these trainings now being widely delivered in classroom setups, they typically lack the arousing action context needed for successful transfer to the operational field, where officers must apply learned skills, particularly when stress levels rise. The study presented here aimed to address this gap by training physiological control skills in an arousing decision-making context. We developed a Virtual-Reality (VR) breathing-based biofeedback training in which police officers perform deep and slow diaphragmatic breathing in an engaging game-like action context. This VR game consisted of a selective shoot/don’t shoot game designed to assess response inhibition, an impaired capacity in high arousal situations. Biofeedback was provided based on adherence to a slow breathing pace: the slower and deeper the breathing, the less constrained peripheral vision became, facilitating accurate responses to the in-game demands. A total of nine male police trainers completed 10 sessions over a 4-week period as part of a single-case experimental ABAB study-design (i.e., alternating sessions with and without biofeedback). Results showed that eight out of nine participants showed improved breathing control in action, with a positive effect on breathing-induced low frequency HRV, while also improving their in-game behavioral performance. Critically, the breathing-based skill learning transferred to subsequent sessions in which biofeedback was not presented. Importantly, all participants remained highly engaged throughout the training. Altogether, our study showed that our VR environment can be used to train breathing regulation in an arousing and active decision-making context.

Effects of Acute Stress on Psychophysiology in Armed Tactical Occupations: A Narrative Review

The ability to perform under extreme pressure is one of the most sought-after qualities in both sports and tactical (military, law enforcement, fire, and rescue, etc.) occupations. While tactical performance relies on both physical and mental capabilities to achieve a desired outcome, it is often hampered by the stressful environments in which these personnel work. The acute stress experienced by tactical personnel can interfere with occupational performance, impacting both physical execution of tasks and decision-making. This narrative review discusses the implications of acute stress on the psychophysiology and physical performance of personnel serving in armed tactical occupations.

A Reasonable Officer: Examining the Relationships Among Stress, Training, and Performance in a Highly Realistic Lethal Force Scenario

Under conditions of physiological stress, officers are sometimes required to make split-second life-or-death decisions, where deficits in performance can have tragic outcomes, including serious injury or death and strained police-community relations. The current study assessed the performance of 122 active-duty police officers during a realistic lethal force scenario to examine whether performance was affected by the officer's level of operational skills training, years of police service, and stress reactivity. Results demonstrated that the scenario produced elevated heart rates (i.e., 150 beats per minute), as well as perceptual and cognitive distortions, such as tunnel vision, commensurate with those observed in naturalistic use of force encounters. The average performance rating from the scenario was 59%, with 27% of participants making at least one lethal force error. Elevated stress reactivity was a predictor of poorer performance and increased lethal force errors. Level of training and years of police service had differential and complex effects on both performance and lethal force errors. Our results illustrate the need to critically reflect on police training practices and continue to make evidence-based improvements to training. The findings also highlight that while training may significantly improve outcomes, flawless performance is likely not probable, given the limits of human performance under stress. Implications for the objective reasonableness standard, which is used to assess the appropriateness of force in courts of law, are discussed.

Emergency physicians' experience of stress during resuscitation and strategies for mitigating the effects of stress on performance

OBJECTIVE

This study explored the perspectives and behaviours of emergency physicians (EPs), regularly involved in resuscitation, to identify the sources and effects of any stress experienced during a resuscitation as well as the strategies employed to deal with these stressors.

METHODS

This was a two-centre sequential exploratory mixed-methods study of EPs consisting of a focus group, exploring the human factors related to resuscitation, and an anonymous survey. Between April and June 2020, the online survey was distributed to all EPs working at Australia's largest two major trauma centres, both in Melbourne, and investigated sources of stress during resuscitation, impact of stress on performance, mitigation strategies used, impact of the COVID-19 pandemic on stress and stress management training received. Associations with gender and years of clinical practice were also examined.

RESULTS

7 EPs took part in the focus group and 82 responses to the online survey were received (81% response rate). The most common sources of stress reported were resuscitation of an 'unwell young paediatric patient' (81%, 95% CI 70.6 to 87.6) or 'unwell pregnant patient' (71%, 95% CI 60.1 to 79.5) and 'conflict with a team member' (71%, 95% CI 60.1 to 79.5). The most frequently reported strategies to mitigate stress were 'verbalising a plan to the team' (84%, 95% CI 74.7 to 90.5), 'implementing a standardised/structured approach' (73%, 95% CI 62.7 to 81.6) and 'asking for help' (57%, 95% CI 46.5 to 67.5). 79% (95% CI 69.3 to 86.6) of EPs reported that they would like additional training on stress management. Junior EPs more frequently reported the use of 'mental rehearsal' to mitigate stress during a resuscitation (62% vs 22%; p<0.01) while female EPs reported 'asking for help' as a mitigator of stress more frequently than male EPs (79% vs 47%; p=0.01).

CONCLUSIONS

Stress is commonly experienced by EPs during resuscitation and can impact decision-making and procedural performance. This study identifies the most common sources of stress during a resuscitation as well as the strategies that EPs use to mitigate the effects of stress on their performance. These findings may contribute to the development of tailored stress management training for critical care clinicians.

Examining the impact of grip strength and officer gender on shooting performance

BACKGROUND

Effective shooting performance relies heavily on sufficient grip strength. However, some standard issue pistols used by police services may have a trigger weight that causes problems for officers with insufficient grip strength, including female officers. The current study aimed to replicate previous findings, which show that grip strength is positively related to shooting performance. We also sought to determine what grip strength is required to achieve proficient scores on a standard police pistol qualification (PPQ) when a heavy trigger weight (i.e., 8lbs-12lbs) is used. Finally, we explored the relationship between officer gender and PPQ scores to determine if grip strength plays a mediating role in this relationship.

METHOD

The dominant hand grip strength (in lbs) of 86 male and 32 female officers were recorded prior to their participation in their agency mandated annual PPQ. Officer gender, grip strength, and PPQ scores were analyzed to explore how they related to one another.

RESULTS

Grip strength significantly impacted officers' ability to pass the PPQ, with female officers possessing lower grip strength compared to male officers, as well as achieving poorer scores on the PPQ. We determined that grip strengths in the range of 80lbs and 125lbs were needed to score approximately 85 % and 90 % on the PPQ, respectively; exceeding that of the average grip strength for the female officers in the study (M = 77.5lbs). Mediation analysis suggested that grip strength may mediate the relationship between officer gender and shooting performance, but studies with more power are needed to confirm that.

CONCLUSION

To improve shooting performance as well as public and police safety, law enforcement agencies may need to consider including grip strength training in their conditioning regime or examine the adoption pistols with a lighter trigger pull weight (e.g., 6lbs).

Coping among public safety personnel: A systematic review and meta–analysis

Public safety personnel (PSP) are routinely exposed to potentially psychologically traumatic events (PPTEs) that, in turn, can result in posttraumatic stress injuries (PTSI), including burnout and increased symptoms of depression and anxiety. However, the longitudinal impact of PPTEs on PSP coping remains unclear. Coping can be operationalized as various strategies (i.e., behaviours, skills, thought and emotion regulation) for dealing with stressors, which are broadly categorized as either approach (adaptive, positive, social support) or avoidant coping strategies (maladaptive withdrawal, avoidance, substance use). This systematic review and meta-analysis aims to evaluate longitudinal coping outcomes among PSP. Thirteen eligible repeated-measures studies explicitly evaluated coping in 1854 police officers, firefighters, and rescue and recovery workers. Study designs included randomized-control trials, within-subject interventions and observational studies. Effect sizes (Cohen's d) at follow-up were described in 11 studies. Separate meta-analyses reveal small (d < 0.2) but non-significant improvements in approach and avoidant coping. Studies were of moderate quality and low risk of publication bias. Heterogeneity in outcome measures, follow-up durations, and study types precluded subgroup analyses. The current findings can inform the development and evaluation of organizational training programs that effectively promote sustained adaptive coping for PSP and mitigate PTSIs.

Testing the Efficacy of a 1-Day Police Decision-Making and Autonomic Modulation Intervention: A Quasi-Random Pragmatic Controlled Trial

Contemporary discourse has identified several urgent priorities concerning police training and education, including: (a) empirically testing and validating the effectiveness of current programming in reducing lethal force decision-making errors; (b) integrating evidence-based content and pedagogical approaches into police curriculum; and (c) understanding the breadth and length of programming necessary to ensure learning and transfer of skills to operational field settings. Widespread calls to identify effective and actionable training programs have been met with numerous research studies, systematic reviews, and policy recommendations that reveal the need to train officers' internal physiological awareness, which is foundational in shaping cognitive decision-making, emotion regulation, and behavior under stressful conditions. Several investigations have shown improvements to both lethal force errors and physiological recovery following a multi-day autonomic modulation (AM) intervention. Immediate and sustained training gains are observed following repeated practice with clinically validated protocols integrated into training scenarios. Despite evidence-based support for AM in addressing the aforementioned priorities, police organizations are faced with limited time and funding for training and education. The goal of the current quasi-random pragmatic controlled trial was to evaluate the effectiveness of a modified 1-day version of an established AM intervention. A sample of active-duty police officers were quasi-randomly assigned to an AM intervention (n = 82) or waitlist control group (n = 105). Lethal force errors and objective measures of autonomic arousal and recovery were measured during reality-based scenarios pre- and post-training and at 12-month follow-up. In contrast to previous investigations of longer AM intervention protocols, no significant training-related improvements to behavioral or physiological outcomes were found immediately post-intervention or at follow-up. The current results suggest that single-day training is insufficient to learn the physiological awareness and regulation skills necessary to perform effectively during lethal force encounters, as demonstrated by a lack of immediate or sustained training effects. Practical considerations, such as resource allocation, that may undermine the effectiveness of implementing evidence-based police training are discussed.

Perception during use of force and the likelihood of firing upon an unarmed person

Stress can impact perception, especially during use-of-force. Research efforts can thus advance both theory and practice by examining how perception during use-of-force might drive behavior. The current study explored the relationship between perceptual judgments and performance during novel close-combat training. Analyses included perceptual judgments from close-combat assessments conducted pre-training and post-training that required realistic use-of-force decisions in addition to an artificially construed stress-inoculation event used as a training exercise. Participants demonstrated significant reductions in situational awareness while under direct fire, which correlated to increased physiological stress. The initial likelihood of firing upon an unarmed person predicted the perceptual shortcomings of later stress-inoculation training. Subsequently, likelihood of firing upon an unarmed person was reduced following the stress-inoculation training. These preliminary findings have several implications for low or zero-cost solutions that might help trainers identify individuals who are underprepared for field responsibilities.

Considering Objective and Subjective Measures for Police Use of Force Evaluation

In spite of significant interest in the application of police use of force (UOF) from organisations, researchers, and the general public, there remains no industry standard for how police UOF is trained, and by extension, evaluated. While certain UOF behaviours can be objectively measured (e.g., correct shoot/no shoot decision making (DM), shot accuracy), the subjective evaluation of many UOF skills (e.g., situation awareness, SA) falls to the discretion of individual instructors. The aim of the current brief communication is to consider the operationalisation of essential UOF behaviours as objective and subjective measures, respectively. Using longitudinal data from a sample of Canadian police officers (n = 57) evaluated during UOF training scenarios, we discuss how objective and subjective measures reflect changes in officer performance over time. Objective lethal force DM was measured as a binary ‘correct–incorrect’ outcome and subjective SA was measured on a 5-point Likert scale ranging from ‘unacceptable’ to ‘exceptional’. Subjective evaluation of SA demonstrated significant changes over time, while DM remained relatively high and stable. Given the practical and professional implications of UOF, we recommend that a combination of objective and subjective measures is systematically implemented at all stages of police UOF training and evaluation (i.e., basic, advanced, in-service).

Proactive psychological programs designed to mitigate posttraumatic stress injuries among at-risk workers: a systematic review and meta-analysis

BACKGROUND

Public safety personnel and frontline healthcare professionals are at increased risk of exposure to potentially psychologically traumatic events (PPTE) and developing posttraumatic stress injuries (PTSI, e.g., depression, anxiety) by the nature of their work. PTSI are also linked to increased absenteeism, suicidality, and performance decrements, which compromise occupational and public health and safety in trauma-exposed workers. Evidence is lacking regarding the effectiveness of "prevention" programs designed to mitigate PTSI proactively. The purpose of this review is to measure the effectiveness of proactive PTSI mitigation programs among occupational groups exposed to PPTE on measures of PTSI symptoms, absenteeism, and psychological wellness.

METHODS

Five electronic databases were searched per PRISMA guidelines for English or French peer-reviewed studies from 2008 to 2019 evaluating PTSI and psychological wellness in adults exposed to occupational PPTE. The risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

We identified 42 studies evaluating 3182 public safety and frontline healthcare professionals, PPTE-exposed educational staff, and miners. Significant overlap was found across program themes that included mindfulness, psychoeducation, resilience promotion, and stress management strategies. Post-program effect sizes were small (SMD < 0.5) to moderate (SMD < 0.8) for reductions in PTSI symptoms and for promoting measures of well-being as indicated by a meta-analysis on 36 studies. There was no evidence for significant reductions in substance use, absenteeism, or biomarkers of distress except for heart rate. Subgroup analyses indicated that multimodal programs effectively improved general psychological health, while resilience programs improved measures of depression, burnout, coping, and resilience. Effect sizes for resilience, depression, and general psychological health improvements were greatest immediately or 1-month post-training, while improvements in PTSD symptoms and coping were larger at longer follow-up. Studies were of moderate quality and risk of bias.

CONCLUSIONS

The current results showcase modest evidence for time-limited reductions in PTSI following participation in holistic programs that promote resilience, stress, and emotion regulation among at-risk workers. Implications for organizational implementation of proactive PTSI mitigation programs and areas of future research are discussed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (CRD42019133534).

Caught in the currents: evaluating the evidence for common downstream police response interventions in calls involving persons with mental illness

The origins of this report, and of the Mental Health and Policing Working Group, can be traced to the unique situation Canadians have faced as a result of the COVID-19 pandemic. The unique circumstances of this global outbreak, which have for many Canadians resulted in serious illness and death, intensified economic uncertainties, altered family and lifestyle dynamics, and generated or exacerbated feelings of loneliness and social dislocation, rightly led the Royal Society of Canada’s COVID-19 Taskforce to consider the strains and other negative impacts on individual, group, and community mental health. With the central role that police too often play in the lives of individuals in mental and (or) emotional crisis, we were tasked with exploring what can be reasonably said about the state of our current knowledge of police responses to persons with mental illness.

Diurnal Cortisol Variation According to High-Risk Occupational Specialty Within Police: Comparisons Between Frontline, Tactical Officers, and the General Population

OBJECTIVE

The aim of this study was to compare diurnal salivary cortisol among high-risk occupational police specialties and the general population (n = 18,698).

METHODS

Tactical and frontline officers provided salivary cortisol samples for 2 days (four times: wake, 30 minutes, 11 hours, and 17 hours post-awakening) and were compared with a general population sample of group field studies utilizing similar methodology. Samples were analyzed for free cortisol concentrations (nmol/L) using chemiluminescence immunoassay.

RESULTS

Repeated-measures mixed-model analysis of variance (ANOVA) revealed significantly greater salivary diurnal cortisol among tactical than frontline officers. Furthermore, both tactical and frontline officers had higher cortisol levels on average at all time points than the general population sample.

CONCLUSION

Results suggest that diurnal cortisol response may be associated with level of risk exposure in hazardous occupational subspecialties within policing compared with the general population.

Relationships Between Heart Rate Variability, Occupational Performance, and Fitness for Tactical Personnel: A Systematic Review

Objectives: Heart Rate Variability has gained substantial interest in both clinical and athletic settings as a measurement tool for quantifying autonomic nervous system activity and psychophysiological stress. However, its uses in tactical work settings, such as military, police, and firefighting environments, remain controversial. Given the physical, mental, and emotional stress public safety personnel face both operationally and in training, heart rate variability measurement may be key in promoting their health, safety and operational effectiveness.

Methods: This study identified, critically appraised, and summarized primary studies investigating relationships between heart rate variability and outcomes of interest to tactical personnel. Key literature databases were searched, and quality assessment checklists were applied to analyze retained literature. The results of the screening and assessment processes, along with key data extracted from each study were summarized and tabulated. Research gaps were also identified to facilitate improvements to how tactical personnel and health or performance providers may best utilize heart rate variability to monitor or promote personnel health and performance, and thereby facilitate public safety.

Results: Twenty studies were included and were all of generally high quality. Cohort size, length of follow-up, measurement objectives, data acquisition, and data analysis all varied considerably across studies, precluding meta-analysis. However, study results correlating heart rate variability and relevant outcomes indicated that overall, heart rate variability is an effective indicator of key fitness and performance elements in the tactical work setting.

Conclusions: Heart rate variability can be an effective health and performance tool in tactical work environments. However, measurement methods must be carefully selected and applied. Further research is required to understand causal relationships. Specifically, larger cohort inclusion and the isolation and study of specific variables unique to public safety work and training may improve the effectiveness of heart rate variability measurement to provide meaningful information to end users and providers.

Psychological and sociological factors influencing police officers' decisions to use force: A systematic literature review

AIM

Police action is frequently discussed and almost always monitored. The aim of this systematic review is to identify the psychological and social factors underlying police officers' decisions to use force.

METHODOLOGY

Scientific articles were selected from six databases (PsycINFO, PsycARTICLES, Psychology and Behavioral Sciences Collection, HeinOnline, ScienceDirect, PubMed).

RESULTS

We found 923 articles matching our search, and 52 were retained based on their results regarding the psychological factors underlying police officers' decisions to use force and the decision-making process itself. We found that the most frequently studied factors were belonging to an ethnic minority, carrying a conducted energy device (CED), the police department's policies and managerial organization, and the environment in which the encounter occurred. However, it seems that the most predictive factor in the decision to use force is the resistance and behavior of the suspect.

The Impact of Acute Stress Physiology on Skilled Motor Performance: Implications for Policing

Investigations of police performance during acutely stressful situations have primarily focused on higher-order cognitive processes like attention, affect or emotion and decision-making, and the behavioral outcomes of these processes, such as errors in lethal force. However, behavioral outcomes in policing must be understood as a combination of both higher-order processes and the physical execution of motor skills. What is missing from extant police literature is an understanding of how physiological responses to acute stress contribute to observed decrements in skilled motor performance at the neuromuscular level. The purpose of the current paper is to fill this knowledge gap in the following ways: (1) review scientific evidence for the physiological (i.e., autonomic, endocrine, and musculoskeletal) responses to acutely stressful exposures and their influence on skilled motor performance in both human and animal models, (2) review applied evidence on occupationally relevant stress physiology and observed motor decrements in performance among police, and (3) discuss the implications of stress physiology for police training and identify future directions for applied researchers. Evidence is compelling that skill decay is inevitable under high levels of acute stress; however, robust evidence-informed training practices can help mitigate this decay and contribute to officer safety.

Stress-Activity Mapping: Physiological Responses During General Duty Police Encounters

Policing is a highly stressful and dangerous profession that involves a complex set of environmental, psychosocial, and health risks. The current study examined autonomic stress responses experienced by 64 police officers, during general duty calls for service (CFS) and interactions with the public. Advancing previous research, this study utilized GPS and detailed operational police records as objective evidence of specific activities throughout a CFS. These data were then used to map officers' heart rate to both the phase of a call (e.g., dispatch, enroute) and incident factors (e.g., call priority, use-of-force). Furthermore, physical movement (i.e., location and inertia) was tracked and assisted in differentiating whether cardiovascular reactivity was due to physical or psychological stress. Officer characteristics, including years of service and training profiles, were examined to conduct a preliminary exploration of whether experience and relevant operational skills training impacted cardiovascular reactivity. Study results provide foundational evidence that CFS factors, specifically the phase of the call (i.e., arrival on scene, encountering a subject) and incident factors (i.e., call priority, weapons, arrest, use-of-force), influence physiological stress responses, which may be associated with short-term performance impairments and long-term health outcomes. Implications of research findings for operational policing, police training, and health research are discussed.

Stress and decision-making in resuscitation: A systematic review

BACKGROUND

During resuscitation decisions are made frequently and based on limited information in a stressful environment.

AIM

This systematic review aimed to identify human factors affecting decision-making in challenging or stressful situations in resuscitation. The secondary aim was to identify methods of improving decision-making performance under stress.

METHODS

The databases PubMed, EMBASE and The Cochrane Library were searched from their commencement to the 13th of April 2019. MeSH terms and key words were combined (Stress* OR "human factor") AND Decision. Articles were included if they involved decision makers in medicine where decisions were made under challenging circumstances, with a comparator group and an outcome measure relating to change in decision-making performance.

RESULTS

22,368 records in total were initially identified, from which 82 full text studies were reviewed and 16 finally included. The included studies ranged from 1995 to 2018 and included a total of 570 participants. The studies were conducted in several different countries and settings, with participants of varying experience and backgrounds. Of the 16 studies, 5 were randomised controlled trials, 3 of which were deemed to have a high risk of bias. The stressors identified were (i) illness severity (ii) socio-evaluative, (iii) noise, (iv) fatigue. The mitigators identified were (i) cognitive aids including checklists, (ii) stress management training and (iii) meditation.

CONCLUSIONS

Human factors contributing to decision-making during resuscitation are identified and can be mitigated by tailored stress training and cognitive aids. Understanding these factors may have implications for clinician education and the development of decision-support tools.

Applying the Theory of Constructed Emotion to Police Decision Making

Law enforcement personnel commonly make decisions in stressful circumstances, where the costs associated with errors are high and sometimes fatal. In this paper, we apply a powerful theoretical approach, the theory of constructed emotion (TCE), to understand decision making under evocative circumstances. This theory posits that the primary purpose of a brain is to predictively regulate physiological resources to coordinate the body's motor activity and learning in the short term, and to meet the body's needs for growth, survival, and reproduction in the long term. This process of managing the brain and body's energy needs, called allostasis, is based on the premise that a brain anticipates bodily needs and attempts to meet those needs before they arise (e.g., vestibular activity that raises sympathetic nervous system activity before standing), because this is more efficient than responding to energetic needs after the fact. In this view, all mental events-cognition, emotion, perception, and action-are shaped by allostasis, and thus all decision making is embodied, predictive, and concerned with balancing energy needs. We also posit a key role for the autonomic nervous system (ANS) in regulating short-term energy expenditures, such that the ANS influences experience and behavior under stressful circumstances, including police decision making. In this paper, we first explain the core features of the TCE, and then offer insights for understanding police decision making in complex, real-world situations. In so doing, we describe how the TCE can be used to guide future studies of realistic decision making in occupations in which people commonly make decisions in evocative situations or under time pressure, such as in law enforcement.

Complex Motor Learning and Police Training: Applied, Cognitive, and Clinical Perspectives

The practices surrounding police training of complex motor skills, including the use of force, varies greatly around the world, and even over the course of an officer’s career. As the nature of policing changes with society and the advancement of science and technology, so should the training practices that officers undertake at both central (i.e., police academy basic recruit training) and local (i.e., individual agency or precinct) levels. The following review is intended to bridge the gap between scientific knowledge and applied practice to inform best practices for training complex motor skills that are unique and critical to law enforcement, including the use of lethal force. We begin by providing a basic understanding of the fundamental cognitive processes underlying motor learning, from novel skill acquisition to complex behaviors including situational awareness, and decision-making that precede and inform action. Motor learning, memory, and perception are then discussed within the context of occupationally relevant stress, with a review of evidence-based training practices that promote officer performance and physiological responses to stress during high-stakes encounters. A lack of applied research identifying the neurophysiological mechanisms underlying motor learning in police is inferred from a review of evidence from various clinical populations suffering from disorders of cognitive and motor systems, including Alzheimer’s and Parkinson’s disease and stroke. We conclude this review by identifying practical, organizational, and systemic challenges to implementing evidence-based practices in policing and provide recommendations for best practices that will promote training effectiveness and occupational safety of end-users (i.e., police trainers and officers).

The Unease Modulation Model: An Experiential Model of Stress With Implications for Health, Stress Management, and Public Policy

Stress has a pervasive, global, and negative influence on individual health. Stress also has negative effects on families, organizations, and communities. Current models of stress are either too general or too detailed to guide effective interventions across the spectrum of medical and social conditions that are stress-related. A new model is needed that explains how stress can have such varied effects and describes how to reduce its harm. The model must also capture both the dynamic nature of stress and its ability to persist and cause chronic effects. The model must guide those who use it in selecting effective interventions and in developing more effective interventions. Ideally, the model will be helpful to people who are experiencing stress and do not have access to professional help. The authors propose a model in an attempt to address the above concerns. The proposed model is called the Unease Modulation Model (UM Model). Briefly, the UM Model separates stress into several elements common to people's experience. The model describes how these elements interact and how those interactions lead to recurring states that are associated with health or illness. Finally, the model enables the person under stress to identify the elements where they will have the most leverage to evoke change and apply specific, effective techniques for that purpose. While the model is experiential, it is also based on mathematical theories of perception, nonlinear dynamics, neurophysiology, and cognitive psychology. In spite of this underlying sophistication, it can be used by those without a medical education. The proposed model has been taught successfully to patients in a clinical setting. The model is now being used in an international training program with police officers to address the long-term stress associated with the career and reduce decision-making errors regarding use of force. This article introduces the model by defining components based on patient descriptions of stress and integrating those into a formal structure. We then demonstrate how the model can be applied to a number of medical and psychiatric conditions. The article concludes by briefly discussing the model's application to family and societal stress-related difficulties.