The emerging research evidence suggests that BWCs demarcate a shift in modern policing. Across thousands of police shifts in different parts of the world, over a long period of time and with millions of residents, BWCs have been found to (a) reduce complaints against officers to nearly zero (93% average reduction, (b) reduce the use of force by up to 50%, and (c) as shown here, reduce overall assaults against officers by nearly two-thirds on the before–after comparisons across most sites (Ariel et al. 2015, 2016a, b; Jennings et al. 2015). Arrest rates have also decreased by nearly one-fifth, and even cooperation with the police has increased as a result of the use of BWCs in policing (Ariel 2016a, b). One can make the argument that no single intervention in the history of policing can claim such substantial, evidenced effects in different jurisdictions (Alpert and Dunham 1997; Bayley 1977; Emsley 2009; Newburn 2005; Reiner 2010; Sherman 1978; Walker 1977; Walker and Katz 2012).

We contextualize the present study within the framework of self-awareness of being observed, which dates back to the work of George Mean on Mind, Self and Society (1934; see also Buss 1980; Duval and Wicklund 1972; Eilan et al. 1995; Morin 2002, 2011; Wicklund 1975). By doing so, this study continues the thread of scholastic work in social psychology and the psychology of the self as a way to explain how the mere presence of a third party in our physical world causes us to modify our perceptions, our motivations, and, ultimately, our behavior. Self-awareness triggers a cognitive process of self-scrutiny and a heightened construction of one’s own identity, which translates into behavior that is more compliant. In our case, we show that instead of the physical presence of a live observer, a small camera affixed to a shirt pocket causes dramatic changes.

However, there are questions about this evidence and the wider applicability of the results reported in these (and other) BWC studies. First, without a theoretical grounding, BWC experiments remain “black boxes” that tell us nothing about how effects are brought about. Second, to what extent can we generalize these findings beyond policing to the human condition and sociological theory more broadly? Below, we discuss such corollaries.

Theoretical implications

The effects of self-awareness on behavior provide a robust explanation for the processes behind deterrence theory as a bridge between psychology and sociology. Sociologists, and particularly criminologists, usually describe the process of deterrence from stimuli (e.g., more visible police, harsher sentences) and their aftermath (“less crime” or “more compliance”; Nagin 2013a; Nagin et al. 2015). Yet, at least in terms of a formal control apparatus, the story has mostly been rather crude: when the intervention appears, some behavioral modification is then observed (Braga et al. 2012, 2014). Precisely how the independent variables affect the dependent variables (i.e., less crime) is unclear (however, cf. Loughran et al. 2012). Self-awareness theory provides a mechanism that fits with the observed. It explains why, on whom, and under which conditions these causal links are created. It illustrates how the social world, physical stimuli, and the self interact (see Fig. 3 in Morin 2004).

Furthermore, focusing on these psychosocial processes offers an approach that is, above all, falsifiable. Deterrence, per se, is an abstract term that is difficult to quantify or measure directly (see discussion in Ariel et al. 2016a). However, more than five decades of research strongly shows that self-awareness can be experimentally induced through a clearly defined apparatus, such as an audience, recording, mirrors, or cameras (Buss 1980; Butterworth 1992, 1995; Carver and Scheier 1978; Cole and Stewart 1999; Davies 2005; Duval and Wicklund 1972; Geller and Shaver 1976; Morin 2002). Recent research even suggests that we can “view” these processes at the neurocognitive level (Cocchini et al. 2009; Dimaggio et al. 2008; Rameson and Lieberman 2009). Having the capacity to measure the treatment effect under controlled conditions is appealing to empiricists. Therefore, beyond deterrence scholars, we suspect that social control as well as rational choice theorists would find merit in the testability of these dimensions as they develop these theories in the future.

“Over-deterrence”

The evidence presented here show strong before–after effects across the various testing sites: the number of assaults on officers was significantly reduced by 61%, with a reliable downward trend in eight out of ten departments. At the same time, our between-group comparisons exhibit an increase rather than a decrease in assaults when comparing treatment with control shifts. Our sensitivity analysis suggests that the between-group effect size remains broadly consistent, usually between a 35% and 48% increase in the odds of assaults against officers per 1000 arrests in treatment conditions compared to the odds in control conditions. Therefore, this multisite study provides evidence of what Merton (1936) referred to as a “perverse effect”. Police departments as a whole experienced significantly fewer assaults—that is, all officers employed in these departments, with or without BWCs, experienced a lower likelihood of assault compared to the period prior to the experiment. At the same time, comparing treatment to control shifts actually showed that self-reported assaults were more likely when cameras were present.

Policing often requires the use of force to subdue aggressive criminals. Under these circumstances, officers must apply force not only to get the job done but also to protect themselves (see review in Friedrich 1980 as well as Sherman 1980, but see a critique in Skolnick and Fyfe 1993). However, we show that by becoming self-aware to a third-party observer such as BWCs, adverse results can emerge. Fig. 4 illustrates that as the degree of discretion decreases, the between-group odds of assaults against officers increases. These are police departments in which officers are fully cognizant that their interactions with the public are documented and that there is a strong likelihood of apprehension for rule violations. In the language of deterrence theory, “sanction threats” (see Ariel and Partridge 2016) were at their peak, and in the language of self-awareness theory, BWCs may have triggered a strong cognitive process of self-scrutiny (i.e., “am I doing the right thing right now?”). BWCs caused a significant reduction in the application of force (Ariel et al. 2016b). This seems like a desired consequence. At the same time, it seems that officers may have been “over-deterred” from applying force when force was in fact needed (Ariel 2017). In certain circumstances, some force is legitimate and, in fact, required. Deterrence was so strong that officers were reluctant to apply the force that was needed to stop force from being applied against them. These are undesired consequences.

We explain officers’ over-deterrence in two (though not necessarily mutually exclusive) ways.

(1) Politeness as weakness. The first line of reasoning suggests that so-called “socially desirable responses” from officers are expected to include politeness and a procedural fairness approach. Some suspects may have interpreted this approach as weakness. As summarized by Kiesling (2007: 667), “Politeness is seen as powerless…men might see politeness as weakness.” In other words, while following the protocol strictly (i.e., weak discretion), officers conveyed a message to offenders that they were somehow vulnerable. As a result, officers may have been more likely to be viewed by suspects as ineffective sanction threats, submissive, or feeble. Against some types of criminals, this perceived weakness translated into physical action in the form of assaults against officers. Furthermore, it is likely that BWCs cause officers to engage verbally (and more politely) rather than resorting to “combat tactics” when, in fact, these tactics are needed. Placing ourselves in the officers’ shoes for a moment, it is unsurprising that BWCs could be linked to an increased rate of assaults. As Stetser (2001: 1) notes, officers were more likely to be assaulted in certain circumstances than others—at night, when suspects were intoxicated or had mental health problems, if the officer was new to the job, and so on. “[O]fficers were assaulted more frequently late at night and on weekends…unemployed and homeless suspects were more likely to assault…suspects who assaulted officers had usually been drinking, were under the influence of drugs, or had a mental disorder; newer officers were more likely to be injured in an assault than more experienced officers; older officers were more likely to be injured in an assault than younger officers…chemical sprays were usually effective in controlling suspects.” Thus, responding with force is a complex and heterogeneous phenomenon. When officers with BWCs are required to subdue certain perpetrators, the cameras may cause officers to behave too softly or can convey the message that the officer would not apply force as needed. Criminals may perceive this message as a “green light” to assault officers during stand-offs without the risk of retaliation by the officer. (2) “Skipping” stages on the force continuum. Our second interpretation of the increased ratio of assaults of officers is that the removal of discretion about turning on BWCs led officers to become over-cautious in using “aggressive voice commands.” Aggressive voice commands can be effective nonphysical restraining tactics. Officers can use firm commands (i.e., request/order/threat; see Fyfe 1988; Toch 1996; Worden 1995; on the “positioning” of voice commands within the force continuum more broadly, see Table 1 in Garner et al. 1995), which often take the form of shouting, cursing, and threats. These are essential tools in the officer’s toolbox against some suspects (for instance, those characterized as risk-taking, violent, and competitive—or the young male syndrome; see Wilson and Daly 1985). Nonphysical voice commands are, in fact, part and parcel of force and may be required in certain circumstances. In fact, for some forces, a “voice command” is third in a gradient continuum of seven stages, after “no force” and “police presence” (see Garner et al. 1995:158). After all, if order can be restored by using foul language rather than the use of a physical response, the former should be preferred; however, this demeanor from an officer does not look good on camera (for further on the use of profanity by officers, see Patton et al. 2017). As argued above, BWCs cause officers to behave in socially desirable ways. Therefore, if officers are reluctant to use these aggressive voice commands because cursing is deemed inappropriate by commanding officers, BWCs may cause officers to avoid using these tactics. As a result, in situations in which some force is needed, BWCs caused officers to skip stages in the force continuum and resort to physical reactions. Thus, officers may be reluctant to use nonphysical force, when such responses are needed, given the circumstances of the interaction. Instead, the situation escalates directly from no-force response into a physical response, without the necessary aggressive voice command. This skipping leads to a violent encounter, with officer injuries. In other words, because the officers feared a response by their supervisors for applying potentially unnecessary or disproportional nonphysical force or foul language, they were induced to apply physical force and consequently placed themselves in a position in which they could be assaulted.

In summary, although psychologists have already identified negative consequences of being observed in the psychopathological sense, we show that adverse consequences can occur in the context of formal control mechanisms as well. Undesirable behavioral manifestations found in previous research on self-awareness include self-harm, avoidance, and increased emotional intensity (Baumeister 1990; Morin and Craig 2000; Moskalenko and Heine 2003; Silvia 2002; Wain 2017). However, our findings suggest that under some circumstances, self-awareness can lead to excessive self-inspection that strips power-holders of their ability to function under extreme situations. We now know that use of force occurs relatively early in most interactions (Willits and Makin 2017), so split-second decision-making—or what Kahneman refers to as System I Thinking (Kahneman 2011)—such as the decision to apply force in the line of duty may suffer, when an officer is aware that his actions are observed and potentially scrutinized.

Unearthing the paradoxical effects

How can we explain the overall reduction in assaults with the simultaneous increase in the odds of assaults in the treatment conditions? The most parsimonious explanation seems to be as follows: overall, officers have changed the way they behave in public. BWCs have caused an organizational learning process that Ariel et al. (2016c) referred to as “contagious accountability”; regardless of whether BWCs were actually worn, police modified their decisions through self-awareness, which translated into different behavior. At the same time, some officers may have inhibited their behavior to such an extent that they did not apply the force necessary to spare them from being injured (what we call being over-deterred). We suspect that better training and experience can potentially counter these effects, and may eventually supplant the need for BWCs in the first place as officers engage better with citizens. However, it seems that BWCs are here to stay—so it is important to carry on studying their effects, intended or otherwise, to ensure they are deployed appropriately.

Hence, while we see an overall reduction in assaults on a year-to-year basis, in most of the participating police departments the treatment conditions experienced an increase in assaults compared to control conditions, while in other departments the reversed result emerged (three departments experienced the most prominent treatment effect; however, the meta-analytic approach, coupled with the statistical sensitivity analyses, indicates that the overall effect is consistent with an increase in assaults). The practical mechanism that enables this pattern is the activation policy embraced by the police department: the more restrictive and tighter the control over officers’ decisions, the more likely they will become self-aware and, by implication, less likely to react to aggressive encounters with the appropriate measures. The outcome of this self-awareness, channeled by the activation policy, is more assaults against the officers. Therefore, whether an officer is recording all of her or his contacts during the shift or only certain interactions with the public, could have profound differences on whether and how the officer changes behavior. Response to being recorded for all interactions could be vastly different than a response when only being recorded during an encounter the officer elects to record. This implies that departments should assist frontline officers in overcoming issues associated with the perceived politeness as weakness as well as the skipping through the stages of the force continuum, as we alluded to earlier, when using BWCs.

A final word about “assaults” against police officers

Different jurisdictions around the globe define “assaults against the police” in different ways. One prominent distinction is between verbal assaults and physical assaults. Verbal abuse can be considered a crime, depending on how vitriolic it is, to what extent it interferes with a police officer in her or his duties, and the circumstances of the case. Physical violence often falls under battery charges, hence the charge of assault and battery in many jurisdictions. However, in many jurisdictions across the United States, “contempt of a cop”, that is, a nonthreatening, nonphysical assault and disrespect of a police officer, is usually not deemed a criminal offense, as such discourse is often protected under a constitutional guard of freedom of speech.Footnote 6 On the other hand, in places like the United Kingdom and other countries, verbal transgressions may be considered notifiable offenses, when they cause “harassment, alarm or distress” of the officer.Footnote 7

In our experiments, we included both verbal as well as physical assaults of officers. We had no way to separate the type of assault, as we were limited by the provisions of our data-sharing agreements with the participating police departments. This caveat must be recognized, as we consider the practical implications of the study. Perhaps, for example, the increase in treatment group compared to control group is the result of an increase in primarily verbal incidents rather than physical assault (i.e., upon being notified that they are on camera, citizens try to taunt officers into misconduct by verbally assaulting them, knowing that officers cannot do much about it). On the other hand, we suspect that at least some of the assaults against of the officers were physical; however, we cannot determine how many. Consequently, it can be the case that officers wearing BWCs were able to de-escalate situations where often verbal abuse is common, but such cooling down while using BWCS is not feasible for situations involving physical abuse of officers. We cannot tell.

As our data do not allow us to make such inferences, we call instead for other scholars to pay a closer attention to the distinction between types of assaults than we could, when designing trials on BWCs. At the same time, we note that both verbal and nonverbal aggression at the workplace are considered as a serious concern. Workplace violence has been found to correlate significantly with psychological strain, burn-out fatigue, perceptions of danger, anxiety, and potentially PTSD (see Alkus and Padesky 1983; Anshel 2000; Burke and Deszca 1986; MacDonald et al. 2003; Robinson et al. 1997). Even if the effect concentrates on nonverbal aggression, a backfiring effect of BWCs on police officers’ wellbeing can lead to both personal as well as organizational adverse consequences, a perverse consequence we ought to minimize.