Police work is often stressful and requires execution of difficult tasks where outcomes are of high consequence. In this paper, we propose that many situations involving police decision-making or performance can be understood as motivated performance contexts: the situations are goal-relevant, involve instrumental cognitive processing, have uncertain outcomes, and require active rather than passive responding ([@ref7]). Motivated performance contexts have been studied extensively in the health and social psychology literature using the biopsychosocial (BPS) model of challenge and threat ([@ref11]; [@ref5]), which articulates the psychological and physiological mechanisms by which stress can sometimes lead to more optimal performance and decision-making (associated with greater challenge orientation) and sometimes lead to poorer performance and decision-making (associated with greater threat orientation; for a review, see [@ref24]). Consistent with this theorizing, existing empirical data on police officers shows that greater physiological arousal in stressful situations is sometimes associated with improvements in performance and decision-making (e.g., [@ref62]; [@ref3]) and sometimes with decrements (e.g., [@ref2]). The BPS model may offer novel insights into the mechanisms by which police performance and decision-making can be optimized even in the face of unavoidable physiological arousal or stress.

This article briefly introduces the BPS model of challenge and threat and reviews recent empirical work that may shed light on the different ways that stress can influence police performance \[broadly defined as the ability to handle critical incidents, involving situational awareness, verbal/non-verbal communication, self-control, or control of the public, (e.g., [@ref12]; [@ref3])\] and decision-making \[defined as critical judgments to engage or not engage in a target behavior, (e.g., [@ref14]; [@ref62])\] across varying contexts, for both better and worse. We conclude by describing a research agenda to enhance the translational value of BPS research to better understand, and ultimately intervene, to improve, complex performance and decision-making behavior in the real world.

The Biopsychosocial Model of Challenge and Threat {#sec1}
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According to the BPS model, challenge and threat represent motivational orientations involving the interplay of affective and cognitive processes that result from the evaluation of situational and task demands relative to one's available resources to cope with them ([@ref7], [@ref8]). More challenge-like states are experienced when a person evaluates his or her coping resources as meeting or exceeding the demands of the situation or task, while more threat-like states are experienced when a person evaluates the situation or task demands as exceeding his or her coping resources ([@ref58], [@ref59]; [@ref7], [@ref8]). These appraisals (sometimes called evaluations) occur on a more subconscious and automatic level, are not under conscious control, and change dynamically over time as perceived demands or resources shift (see, [@ref50]; [@ref56]). Originally, the factors contributing to the evaluation of task demands (e.g., perceptions of danger, uncertainty) were hypothesized as independent from those governing the evaluation of coping resources (e.g., dispositional factors, social support). However, more recent theorizing suggests that several factors are likely implicated in evaluations of both demands and resources (e.g., required effort, knowledge and skills, safety/danger; see [@ref6]). This is consistent with the idea that challenge and threat are not fixed and dichotomous, but rather malleable states that exist as opposing endpoints of a continuum ([@ref56]; [@ref28]).

The BPS model's focus on appraisals of demands and resources developed out of Lazarus' theory of cognitive appraisal (see [@ref34]; [@ref21]; [@ref33]), which has been utilized in the policing literature to explore the role of cognitive appraisals in stress and performance among law enforcement personnel (e.g., [@ref32]; [@ref22]). Lazarus introduced the terms "challenge" and "threat" as part of his theory, emphasizing that stress was not a unitary construct, but a system of responses that could be altered by changing one's perception of a stressor ([@ref34]; [@ref21]). In Lazarus' theory, "challenge" and "threat" reflect valenced appraisals that contributed to perceptions of a situation's self-relevance and the potential for a situation to confer gains or losses, respectively (for review, see [@ref28]). In the BPS model, challenge and threat responses *only* occur in self-relevant contexts and are associated with evaluations of the relative balance of demands and coping resources ([@ref7], [@ref8]). Critically, in the BPS model, unlike in Lazarus' theory, the patterns of cognitive appraisals associated with challenge and threat are posited to engender reliably distinct patterns of physiological arousal (e.g., [@ref11]; [@ref7]).

The basis for using physiological responses as indicators of challenge and threat in the BPS model is derived from the work of [@ref18] who theorized that quickly mobilizing energy resources during motivated performance, *via* the sympathetic-adrenomedullary axis, or SAM (as opposed to slowly *via* hypothalamic pituitary axis, or HPA), was a marker of "physiological toughness" because it was associated with favorable outcomes like increased performance, more emotional stability, and lower anxiety, leaving individuals more likely to appraise situations positively (for review see, [@ref55]). Both challenge and threat states are theorized to involve activation of the SAM axis, and thus are associated with increases in indices of cardiovascular arousal (e.g., increased heart rate) and sympathetic nervous system control of the heart (i.e., ventricular contractility, measured as the inverse of pre-ejection period, the time between the electrical stimulus initiating ventricular contraction and opening of the aortic valve). Increases in ventricular contractility and heart rate are frequently interpreted as indicators of task engagement in motivated performance contexts ([@ref55], [@ref56]). Experiencing a more challenge-like orientation is also associated with increased cardiac output (CO; volume of blood circulated per minute) accompanied by decreased systemic vascular resistance, typically measured as total peripheral resistance (TPR), the extent of overall constriction in the peripheral vasculature ([@ref18]; [@ref7]). In more challenge-like states, the heart beats harder and faster and moves blood more efficiently to the periphery, benefiting organ function and motor activity. Threat-like states involve activation of the SAM axis and the HPA, which inhibits decreases in vasoconstriction in the periphery. Thus, experiencing a more threat-like orientation is associated with no change or even increases in vascular resistance combined with more modest increases in cardiac output and ventricular contractility (i.e., blood flow is unable to reach and circulate in the peripheral vasculature as efficiently). While challenge-like patterns of physiological responding are interpreted as beneficial for the body, threat-like patterns of physiological responding are considered detrimental to energy mobilization ([@ref58], [@ref59]). Moreover, the pattern of cardiovascular reactivity associated with threat-like states is theorized to have deleterious impacts on long-term cardiovascular health if experienced repeatedly over time ([@ref38],[@ref41]; [@ref5]; [@ref35]).

Research Using the Biopsychosocial Model {#sec2}
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Although the BPS model has yet to be directly explored in real-world police decision-making contexts, challenge and threat orientations have been shown to influence decision-making and performance in other stressful, high-stakes environments. For example, challenge orientation (physiological and psychological) has been associated with better performance in situations that unfold over longer durations of time such as surgery ([@ref44]), cricket and baseball seasons ([@ref10]; [@ref61], respectively), flight simulation ([@ref65]), negotiations ([@ref47]), and semester grades (e.g., [@ref57]). However, greater challenge orientation also confers benefits in visual attention (e.g., [@ref43]; [@ref64]), motor performance (e.g., [@ref43], [@ref46], [@ref44], [@ref45]), attentional control (e.g., [@ref63], [@ref65], [@ref64]), and working memory (e.g., [@ref30]; [@ref19]; [@ref20]). As such, the BPS model may offer unique insight for improving police performance under stress both in situations that unfold over longer durations of time (e.g., assessing danger during a robbery; [@ref3]) and in rapid decision-making contexts (e.g., lethal force decisions; [@ref14]).

Although a complete review of the BPS literature examining performance under stress is outside the scope of this article, we briefly highlight empirical findings in content areas that are particularly relevant to police decision-making and performance given the current sociopolitical context in the United States.

Stigmatization and Minority Status {#sec3}
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Empirical studies with lay people have consistently demonstrated that, relative to White targets, participants are significantly quicker to shoot armed Black targets, significantly slower to "not shoot" unarmed Black targets, and have a lower shooting threshold for Black targets (i.e., tend to favor the "shoot" response) in computer-based shooting simulations ([@ref14],[@ref13], [@ref15]; [@ref49]; [@ref37]). Laboratory research with real police officers on comparable tasks has demonstrated similar biases in reaction times for Black targets, though police officers generally demonstrate less bias in behavior and make fewer errors than lay individuals overall (see [@ref14]). Critically, research suggests these biases may be mitigated by a number of contextual and personal factors (for discussion, see [@ref29]). For instance, police officers are less likely to demonstrate biases on shooting simulation tasks when they report having more positive interactions with Black people in their daily lives ([@ref48]) or report less overestimation of crime rates for minorities ([@ref51]), and studies with lay individuals have demonstrated reduced biases on tasks where counter-stereotypical targets (i.e., unarmed Black targets) are encountered more frequently ([@ref13]).

These findings on shooting simulation tasks are consistent with empirical work from the BPS model on challenge and threat responding during interactions with individuals from stigmatized groups. For example, [@ref9] "stigma-threat hypothesis," posited that effort exerted during interactions with individuals from stigmatized groups increases because non-stigmatized individuals monitor their behavior more carefully to appear unaffected and avoid accusations of prejudice ([@ref9]; [@ref16]). Even for individuals who do not hold blatant prejudices, interactions with individuals from stigmatized groups can evoke knowledge of negative stereotypes, resulting in increasing efforts to monitor behavior and suppress stereotype-consistent thoughts ([@ref17]; [@ref67]). Indeed, researchers have consistently demonstrated that participants show patterns of cognitive appraisal and cardiovascular activity consistent with more threatened orientations during interactions with individuals from stigmatized groups ([@ref9]; [@ref39], [@ref38]). For instance, White participants performed worse on a joint word-finding task and were more likely to produce cardiovascular patterns associated with threat-like states (e.g., increased TPR) when interacting with Black confederates or confederates of low socioeconomic status compared to White confederates ([@ref39]).

However, researchers have found that increased interaction with stigmatized groups is positively related to challenge-like physiological responses during intergroup interactions ([@ref9]). These findings parallel those from studies involving police officers ([@ref48]) and lay individuals ([@ref14]), where increased exposures to individuals from stigmatized groups, in safe contexts, reduced racial bias in shooting simulation tasks. This suggests that interventions targeted toward increasing positive social interactions with individuals from stigmatized or minority populations may help increase the likelihood of exhibiting more challenge-like orientations during intergroup interactions to the benefit of performance and decision-making.

Power {#sec4}
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Research on the BPS model has examined the nuanced ways in which social status and power influence patterns of biopsychological activity. Specifically, individuals high in social status or power tend to experience more challenge-like states during social interactions with people of lower status (e.g., [@ref54]; [@ref52]; [@ref53]). For example, participants prompted to recall incidents in their lives where they had a lot of power or who were randomly assigned to a high-power role (e.g., given more leverage in a negotiation task) exhibited more challenge-like appraisals and cardiovascular activity than participants randomly assigned to low-power comparison conditions ([@ref53]). Consistently, [@ref1] found that police officers who self-reported higher social status exhibited more approach-oriented or challenge-like patterns of physiological reactivity, including increased heart rate, cardiac output, and testosterone reactivity, during a simulated interaction with a disgruntled citizen.

Critically, research suggests that the relationship between power and biopsychological responding relies on the stability of the power hierarchy; those high in status show more threat-like responses when their status is perceived as unstable or illegitimate ([@ref54]; [@ref52]). These findings may offer insight into why tense situations can escalate quickly depending on social dynamics. Specifically, when police officers feel secure in their status as an authority figure and do not believe they are being undermined by a suspect or civilian, they may be more likely to engender challenge-like orientations to the benefit of decision-making and performance in that context. Moreover, research suggests that, when individuals' social identities are threatened, engaging in self-affirmation strategies engenders more challenge-like patterns of physiological reactivity ([@ref16]). Thus, it may prove beneficial to develop interventions to help police officers maintain stable perceptions of their status (e.g., by engaging in self-affirmation strategies) even when interacting with suspects or other civilians who are questioning their legitimacy or status.

The Biopsychosocial Model and Police Decision-Making: A Research Agenda {#sec5}
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Although the BPS model has proven useful in examining performance under stress across a variety of motivated performance contexts (see [@ref4]; [@ref24]), there remains a critical need for translational research investigating its utility in real-world situations, specifically in the context of police interactions and decision-making. A recent field study demonstrated the viability of using the BPS model to examine and predict biopsychological responding among first responders, including police officers, in an ecologically valid, high-stress situation: a multi-faceted drill simulating the response to a plane making an emergency landing with a fire and injured passengers onboard ([@ref66]). Consistent with the BPS model, more challenge-like appraisals among first responders were associated with better self-assessed performance during the drill ([Figure 1](#fig1){ref-type="fig"}).

![Stress/coping ratios predict self-assessed performance (rated on a 5-point scale) during an emergency training drill. Ratio of self-reported stress to self-reported coping ability is shown on the *x*-axis, with higher numbers indicating more threat-like appraisals and lower numbers indicating more challenge-like appraisals. An estimate of *R*^2^ is provided in figure, though should be interpreted with caution due to sample size.](fpsyg-10-01800-g001){#fig1}

Data from this field study highlight several critical theoretical and methodological considerations for researchers interested in pursuing translational research examining the relevance of the BPS model in realistic decision-making and performance scenarios. First, the vast majority of research using the BPS model has focused on group comparisons between samples of individuals exhibiting more threatened versus more challenged appraisals, failing to examine challenge and threat responses at the level of the individual (though see [@ref50]). As a result, little is known about why, given identical circumstances, one individual may be more challenged while another is more threatened (for review, see [@ref31]). Note the presence of robust individual differences observed in the recent field study, even within a highly evocative, personally-relevant context ([Figure 1](#fig1){ref-type="fig"}; [@ref66]). According to [@ref18], exposure to repeated intermittent stressors could result in a proneness to challenge-like responding under stress, a pattern of response linked to both increased emotional stability and immune system enhancement ([@ref56]). This is consistent with a number of clinical and therapeutic approaches (e.g., cognitive behavior therapy, desensitization therapy, stress inoculation training) which posit that trainings involving repeated exposure to small stressors that the individual can cope with successfully may bolster more effective, challenge-like performance in the face of future, unknown stressors.

In addition, research using the BPS model has focused almost exclusively on static assessments of challenge and threat responding and has not examined how patterns of physiological activity or cognitive appraisals change dynamically over time as a stressful context unfolds. The recent field study revealed dynamic changes in physiological and SNS arousal over time throughout the training, and these patterns of change varied markedly across individuals ([Figure 2](#fig2){ref-type="fig"}; [@ref66]). The focus on static assessment means important information about early detection and genesis of challenge-like and threat-like states in the face of stressors remain unknown. Information concerning the time course of psychobiological states might be useful for designing early intervention systems involving biofeedback or for identifying critical time points at which individual interventions might be most effective at mitigating threat-like physiological patterns as they unfold in real time.

![Electrodermal activity and estimated heart rate for five individuals throughout emergency training drill. Time in minutes relative to the start of the drill is shown on the *x*-axis. The start of the drill is marked with a solid vertical line and the end of the drill is marked with a dashed vertical line on each graph. **(A)** shows electrodermal activity in microsiemens (μS) for the five participants (PP1, PP2, PP3, PP4, and PP5) throughout the study. **(B)** shows estimated heart rate (HR) in beats per minute for the same five participants throughout the study. Each row contains EDA and HR data for the same participant. For both physiological variables, an average value was taken for each 1 min of recording, and these averages are plotted here.](fpsyg-10-01800-g002){#fig2}

Future translational work would also benefit from the inclusion of complementary methodological approaches used less frequently in research on the BPS model. For instance, audio-visual data recorded continuously during a motivated performance context would be invaluable for elucidating how and why challenge and threat orientations shift dynamically as a context unfolds. Qualitative interviews with participants could shed light on important individual differences related to the tendency to experience more challenge-like orientations under stress, or could suggest potential mechanisms for future exploration of factors contributing to appraisals of demands and/or resources. Considering the myriad contexts in which police officers must optimize performance and decision-making, future translational research would benefit from the inclusion of more diverse, real-world contexts (e.g., situations involving different combinations of cognitive, affective, social, and motoric features). Comparing diverse scenarios may offer insights on the psychological and physiological mechanisms by which challenge and threat orientations influence performance or decision-making across contexts.

Conclusion {#sec6}
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The BPS model appears well-suited for studying the psychophysiology of police performance and decision-making because challenge- and threat-like states are relevant across a wide range of social evaluative and motivated performance domains (e.g., [@ref4]), are associated with consistent patterns of cognitive appraisal and cardiovascular reactivity ([@ref5]), and have been shown to predict important behavioral and decision-making outcomes in stressful contexts (see [@ref24]). Moreover, while threat-like states have not been *directly* linked to health outcomes, prolonged physiological activation (particularly in the HPA) can result in profound negative health consequences (e.g., [@ref36]). Thus, research examining challenge and threat responding among police officers in the line of duty stands to improve early detection of individuals at risk for the negative health outcomes (e.g., cardiovascular disease) that are associated with careers in law enforcement ([@ref23]).

Author Contributions {#sec7}
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DK and JW drafted the manuscript. ES provided substantial edits and feedback on the manuscript.

Conflict of Interest Statement {#sec8}
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The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

[^1]: Edited by: Eamonn Patrick Arble, Eastern Michigan University, United States

[^2]: Reviewed by: Craig Bennell, Carleton University, Canada; Edwina Light, University of Sydney, Australia

[^3]: This article was submitted to Health Psychology, a section of the journal Frontiers in Psychology
