Cardiac autonomic functions and the emergence of violence in a highly realistic model of social conflict in humans

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).

The effects of expected and unexpected stress on inappropriate aggression in simulated police interventions

Here we performed a before-after ABA-design study in police cadets (N = 82) to compare the effects of unexpected (event-triggered) and expected (anticipatory) stressors on aggression. On the first day of the study, participants filled in the Buss-Perry Aggression Questionnaire (BPAQ) and the Barratt Impulsiveness Scale (BIS) and were fitted with heart rate (HR) monitors, which remained attached till the end of the study. On day 2, they were instructed to perform a police intervention in a realistic training environment. The intervention was preceded either by a warning or by a reassuring audio recording that forecasted violent or routine interventions, respectively. Both groups encountered hostile suspects at the intervention site, the behavior of which, however, did not justify the use of force e.g., aggression. The warning resulted in a gradually developing anticipatory stress as shown by HRs. Cadets exposed to the reassuring audio recording showed minimal anticipatory stress but responded to the hostile suspects by an abrupt increase in HRs, which was missing in the warned group. The magnitude of HR responses was similar in the two groups, only their temporal evolution differed. Although aggression showed some associations with BPAQ and BIS scores, the main predictors of behavior were HR changes according to a Multiple Regression analysis. The gradually developing anticipatory stress was associated with low, whereas the abrupt increase in HRs was associated with high aggression. Our findings suggest that the anticipation of a stressful event improves behavioral control whereas an unexpected stress strongly promotes aggression.

Non-angry aggressive arousal and angriffsberietschaft: A narrative review of the phenomenology and physiology of proactive/offensive aggression motivation and escalation in people and other animals

Human aggression typologies largely correspond with those for other animals. While there may be no non-human equivalent of angry reactive aggression, we propose that human proactive aggression is similar to offense in other animals' dominance contests for territory or social status. Like predation/hunting, but unlike defense, offense and proactive aggression are positively reinforcing, involving dopamine release in accumbens. The drive these motivational states provide must suffice to overcome fear associated with initiating risky fights. We term the neural activity motivating proactive aggression "non-angry aggressive arousal", but use "angriffsberietschaft" for offense motivation in other animals to acknowledge possible differences. Temporal variation in angriffsberietschaft partitions fights into bouts; engendering reduced anti-predator vigilance, redirected aggression and motivational over-ride. Increased aggressive arousal drives threat-to-attack transitions, as in verbal-to-physical escalation and beyond that, into hyper-aggression. Proactive aggression and offense involve related neural activity states. Cingulate, insular and prefrontal cortices energize/modulate aggression through a subcortical core containing subnuclei for each aggression type. These proposals will deepen understanding of aggression across taxa, guiding prevention/intervention for human violence.

Dynamics of parasympathetic activity in violent incarcerated offenders before, during, and in recovery from an emotional inhibition task

Dynamics of the autonomic nervous system (ANS) are hypothesized to play a role in the emergence of interpersonal violence. In the present study, we examined continuous activities of the inhibitory parasympathetic pathway of the ANS through the root mean square of successive differences between normal heartbeats (RMSSD) in 22 male offenders who committed interpersonal violence and 24 matched controls from the general population across three successive phases: resting baseline, while performing an emotional Go/No-Go task, and post-task recovery. Results showed that across the three phases, the offender group presented lower RMSSD at baseline (p_FDR = .003; Cohen's d =  - 1.11), but similar levels during the task, attributed to a significant increase in their RMSSD level (p_FDR = .027, Cohen's d =  - 1.26). During recovery, while no distinction between the two groups was found, both groups showed signs of recovering toward baseline values. These findings suggest that violent incarcerated offenders can flexibly engage parasympathetic resources to meet environmental challenges. This underscores the necessity of considering parasympathetic dynamics and its respective mobilization/flexibility to better understand ANS profiles underlying interpersonal violence as well as its potential utility in designing more tailored interventions.

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.

Comparison of the Cardiovascular Effects of Extreme Psychological and Physical Stress Tests in Male Soccer Players

Background: The purpose of our study was to compare the physiological effects of extreme physical and psychological stress tests in male soccer players, since these two types of stress apply to athletes with high performance requirements. Methods: A total of 63 healthy male soccer players participated in this study, all of whom underwent both of the tests. A physical stress test was carried out in an exercise physiology laboratory, where subjects completed an incremental treadmill running test to full exhaustion, and a psychological test was performed in a military tactical room, where subjects met a street offence situation. Heart rate variability (HRV) and blood pressure (BP) were recorded directly before, immediately after, and 30 min after the stress tests. Results: The majority of HRV indices changed significantly in both stress protocols. Inverse, significant changes (positive for the physical test, negative for the psychological test, p < 0.001) were found when comparing the alterations of HRV indices between the tests. Significant differences were found in the changes in systolic (p = 0.003) and diastolic (p < 0.001) BP between the test protocols, and also between the baseline and post-test measurements (p < 0.001). Conclusion: Both HRV and BP are sensitive physiological parameters to measure the impact of extreme physical and/or psychological stress

Monitoring stress and allostatic load in first responders and tactical operators using heart rate variability: a systematic review

BACKGROUND

Awareness of the cumulative stress placed on first responders and tactical operators is required to manage acute fatigue, which can impair occupational performance, and may precipitate negative chronic health outcomes. The aim of this review was to investigate the utility of heart rate variability (HRV) to monitor stress and allostatic load among these populations.

METHODS

A systematic search of Academic Search Complete, MEDLINE complete, PsycINFO, SPORTDiscus and Scopus databases was conducted. Eligibility criteria: original peer reviewed research articles, written in English, published between 1985 and 2020, using human participants employed as a first responder or tactical operator, free from any psychological disorder.

RESULTS

Of the 360 articles screened, 60 met the inclusion criteria and were included for full text assessment. Articles were classified based on single or repeated stressor exposure and the time of HRV assessment (baseline, during stressor, post stressor). Singular stressful events elicited a reduction in HRV from baseline to during the event. Stressors of greater magnitude reduced HRV for extended durations post stressor. Lower resting HRV was associated with lower situational awareness and impaired decision-making performance in marksmanship and navigation tasks. There were insufficient studies to evaluate the utility of HRV to assess allostatic load in repeated stressor contexts.

CONCLUSION

A reduction in HRV occurred in response to acute physical and cognitive occupational stressors. A slower rate of recovery of HRV after the completion of acute occupational stressors appears to occur in response to stressors of greater magnitude. The association between lower HRV and lower decision-making performance poses as a useful tool but further investigations on within subject changes between these factors and their relationship is required. More research is required to investigate the suitability of HRV as a measure of allostatic load in repeated stress exposures for fatigue management in first responder and tactical operators.

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.

The Complex Associations Between Early Childhood Adversity, Heart Rate Variability, Cluster B Personality Disorders, and Aggression

Early childhood adversity can cause an imbalance in the autonomic function, which may in turn lead to the development of trauma-spectrum disorders and aggressive behavior later in life. In the present study, we investigated the complex associations between early adversity, heart rate variability (HRV), cluster B personality disorders, and self-reported aggressive behavior in a group of 50 male forensic inpatients (M age = 41.16; SD = 10.72). Structural Equation Modeling analysis revealed that patients with cluster B personality disorders were more likely to have adverse early childhood experiences and reduced sympathetic dominance in response to a threat than patients without cluster B personality disorders. In addition, HRV and cluster B personality disorders did not significantly mediate the association between early childhood adversity and self-reported aggressive behavior. These findings are important for clinical practice to facilitate specific treatment programs for those affected.

The relationship between physiological reactivity to provocation and emotion dysregulation with proactive and reactive aggression

Biological theories of aggression propose that autonomic nervous system (ANS) hypo-reactivity may be more specific to proactive aggression, whereas ANS hyper-reactivity may be specific to reactive aggression. However, the research findings in this area are mixed. Furthermore, no study to date has examined whether emotion dysregulation moderates the aggression - ANS relationship. The present study examined electrodermal activity (EDA), respiratory sinus arrhythmia (RSA) and heart rate (HR) reactivity in 76-undergraduate participants (29 men, mean age = 21.49) in response to a provocation task relative to baseline. Results showed that blunted HR reactivity was associated with increased proactive aggression. RSA augmentation and blunted EDA reactivity were both associated with increased proactive and reactive aggression, but only among those above the sample mean on emotion dysregulation. Thus, emotion dysregulation may play a key role in the relationship between ANS reactivity and both reactive and proactive aggression.

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.

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.

A time to fight: Circadian control of aggression and associated autonomic support

The central circadian clock, located in the suprachiasmatic nucleus of the mammalian hypothalamus (SCN), regulates daily behavioral rhythms including the temporal propensity for aggressive behavior. Such aggression propensity rhythms are regulated by a functional circuit from the SCN to neurons that drive attack behavior in the ventromedial hypothalamus (VMH), via a relay in the subparaventricular zone (SPZ). In addition to this pathway, the SCN also regulates sleep-wake and locomotor activity rhythms, via the SPZ, in a circuit to the dorsomedial hypothalamus (DMH), a structure that is also known to play a key role in autonomic function and the sympathetic "fight-or-flight" response (which prepares the body for action in stressful situations such as an agonistic encounter). While the autonomic nervous system is known to be under pronounced circadian control, it is less apparent how such autonomic rhythms and their underlying circuitry may support the temporal propensity for aggressive behavior. Additionally, it is unclear how circadian and autonomic dysfunction may contribute to aberrant social and emotional behavior, such as agitation and aggression. Here we review the literature concerning interactions between the circadian and autonomic systems and aggression, and we discuss the implications of these relationships for human neural and behavioral pathologies.

Reducing Lethal Force Errors by Modulating Police Physiology

OBJECTIVES

The aim of this study was to test an intervention modifying officer physiology to reduce lethal force errors and improve health.

METHODS

A longitudinal, within-subjects intervention study was conducted with urban front-line police officers (n = 57). The physiological intervention applied an empirically validated method of enhancing parasympathetic engagement (ie, heart rate variability biofeedback) during stressful training that required lethal force decision-making.

RESULTS

Significant post-intervention reductions in lethal force errors, and in the extent and duration of autonomic arousal, were maintained across 12 months. Results at 18 months begin to return to pre-intervention levels.

CONCLUSION

We provide objective evidence for a physiologically focused intervention in reducing errors in lethal force decision-making, improving health and safety for both police and the public. Results provide a timeline of skill retention, suggesting annual retraining to maintain health and safety gains.

Avoidant Responses to Interpersonal Provocation Are Associated with Increased Amygdala and Decreased Mentalizing Network Activity

When intentionally pushed or insulted, one can either flee from the provoker or retaliate. The implementation of such fight-or-flight decisions is a central aspect in the genesis and evolution of aggression episodes, yet it is usually investigated only indirectly or in nonsocial situations. In the present fMRI study, we aimed to distinguish brain regions associated with aggressive and avoidant responses to interpersonal provocation in humans. Participants (thirty-six healthy young women) could either avoid or face a highly (HP) and a lowly (LP) provoking opponent in a competitive reaction time task: the fight-or-escape (FOE) paradigm. Subjects avoided the HP more often, but retaliated when facing her. Moreover, they chose to fight the HP more quickly, and showed increased heart rate (HR) right before confronting her. Orbitofrontal cortex (OFC) and sensorimotor cortex were more active when participants decided to fight, whereas the mentalizing network was engaged when deciding to avoid. Importantly, avoiding the HP relative to the LP was associated with both higher activation in the right basolateral amygdala and lower relative activity in several mentalizing regions [e.g., medial and inferior frontal gyrus (IFG), temporal-parietal junction (TPJ)]. These results suggest that avoidant responses to provocation might result from heightened threat anticipation and are associated with reduced perspective taking. Furthermore, our study helps to reconcile conflicting findings on the role of the mentalizing network, the amygdala, and the OFC in aggression.

Changes in Heart Rate Variability Recorded in Natural Situation with T-Shirt Integrated Sensors and Level of Observed Behavioral Excitation: A Pilot Study of Patients with Intellectual Disabilities and Psychiatric Disorders

BACKGROUND

The present study investigates the possibilities of using heart rate variability (HRV) parameters as physiological markers that precede increase in observed behavioral excitation of intellectually disabled individuals. The ability to recognize or predict such patterns, especially in patients showing unpredictable reactions and language deficiencies, might be a major step forward in clinical research.

METHOD

Thirteen volunteers with intellectual disabilities, who had suffered of at least one event of overt aggression in the preceding 3 months, participated to the study. The protocol consists in the acquisition of continuous electrocardiogram (ECG) throughout approximately two times of 8 h in natural situation, using a T-shirt integrated with sensors. Simultaneously, an observer evaluates the patient's level of overt excitation from calm (level 1) to extremely tense (level 5) and send online via Bluetooth these triggers into the ECG signals. The HRV indexes were then estimated offline on the basis of the inter-beat intervals recorded by the ECG, independently for the 30 min preceding each behavioral tension marking point, averaged, and compared through non-parametric Wilcoxon matched-pairs test. Of these, the RMSSD and LF/HF calculations were used to observe the fluctuations of inhibitory activity and cardiovagal balance through different tension states.

RESULTS

Seven individuals have sufficient reliable data for analysis. They have reached at least a level 3 of behavioral excitation (moderately tense) or more (very to extremely tense, level 4 and 5) and have been retained for further analysis. In sum, a total of 197 periods of tension were kept, made up of 46 periods of slight excitation (level 2), 18 of moderate excitation (level 3), 10 of high excitation (level 4), and 5 of extreme agitation (level 5). Variations in the HRV as a function of degree of excitation are observed for RMSSD index only (inhibitory parasympathetic activity). The changes from calm to increasing levels of excitation are characterized by a significant downfall in RMSSD index when patients were evaluated to be in a very high level of tension (level 4).

CONCLUSION

The presence of precursors to agitation, reflected in the falling-off of parasympathetic activity, offers potentially interesting prospects for therapeutic development.