Trust in law enforcement is key for public cooperation in crime control and increasing police accountability (Jackson and Bradford, 2010; Tyler, 2011). Most studies of police trust use subjective assessments obtained through a survey where respondents answer questions about a general concept of police, mark their willingness to cooperate with law enforcement directives, and indicate their overall belief in police legitimacy (Goldsmith, 2005; Mazerolle et al., 2013). Survey approaches suggest one’s assessment of law enforcement impacts police-community relationships (Tyler, 2011; Mazerolle et al., 2013).

However, many people do not trust the police. Distrust of police is higher for African American and Hispanic/Latine people in the United States (Weitzer and Tuch, 2004a,b; Brunson, 2007). Media portrayals of police violence in society condition one’s views of police and result in negative assessments of law enforcement (Boudreau et al., 2019; Nägel and Nivette, 2022). Unfavorable views of police may impact one’s likelihood of complying with officer directives, participating in crime prevention efforts, or otherwise cooperating with law enforcement.

The police stand out from regular civilians because of their uniformed presence, which can be considered a priming stimulus. Priming refers to the activation of certain concepts or ideas in a person’s mind, which can influence subsequent thoughts, judgments, or behaviors (Scheufele and Tewksbury, 2007). Police attire carries strong associations and elicit thoughts and assumptions about authority, security, law enforcement and the behaviors typically associated with the police. Depending on one’s lived experience and attitude toward law enforcement, the uniform may evoke positive feelings of safety and trust, while for others it may trigger fear and anxiety.

One interesting possibility is that one’s level of trust in police can influence how they perceive the facial expressions displayed by law enforcement officers. Various factors can affect our subjective perception of faces, including early experiences (Pollak and Sinha, 2002), facial width-to-height ratio (Geniole et al., 2015) cross-race effects (Young et al., 2012), facial aging (Grondhuis et al., 2021), eyewear (Brunet and Sharp, 2020), and priming effects (Brunet, 2023). A quick glance at candidate’s faces can even predict election outcomes (Todorov et al., 2005). Additionally, personal traits and mental states can impact emotional stimuli processing. EEG studies, for example, have shown that individuals with different personality traits exhibit different neural information processing when making emotional judgments (Hamann and Canli, 2004; Fink, 2005). Anxiety levels are yet another factor that can influence emotional processing, as demonstrated by a study revealing that self-reported anxiety strongly affects attentional bias, neural activations (Fox et al., 2005), and gaze direction (Im et al., 2017), in response to threat-related stimuli. Another study (Doty et al., 2013) identified a significant positive correlation between trait anxiety, as determined by a questionnaire completed by the participants, and the ability to detect fearful faces. Based on the available research, it appears one’s social attitudes toward police may impact facial processing.

We propose that an individual’s social attitudes toward the police significantly influence how they interpret the emotional expression of law enforcement officers (Hugenberg and Bodenhausen, 2003; Hugenberg and Bodenhausen, 2004). Faces serve an important social function and pre-existing views, such as stereotypes, can inadvertently shape our perceptions of others through implicit bias. In the context of law enforcement, negative attitudes toward police may lead to harsher judgments of facial expressions. Notably, these negative judgments may be more pronounced in Black and Hispanic communities (Vogel, 2011; Kang and Bodenhausen, 2015; Peck, 2015; Bolger et al., 2021) as these populations have poor relationships with law enforcement relative to White people. Negative views of police may stem from a fear of victimization, neighborhood context, vulnerability, media-cultivated fear, or personal or vicarious experiences with police (Warr, 1990; Hagan et al., 2005; Farrall et al., 2009; Stevens and Abernethy, 2018; Miethe et al., 2019; McCarthy et al., 2020; Goffin, 2022; Pickett et al., 2022). The police may elicit feelings of anger, sadness, or depression and active prejudicial thoughts as they are considered an “outgroup” (DeSteno et al., 2004; Pichon et al., 2012). The extent of these negative attitudes can influence how one perceives emotional cues from police and non-police. The police are readily distinguishable from civilians by their distinctive uniformed appearance and the clothing, in and of itself, poses no threat to an individual. However, society ascribes meaning to clothing, recognizing it as the uniform of formal agents of social control. Consequently, an officer’s uniform may evoke latent cognitions and emotions associated with one’s preconceived notions of police. One might expect social attitudes toward police to shape one’s perception of the emotional expressions of a person enveloped in a uniform.

Our goal is to explore potential differences in how people perceive facial expressions displayed by police officers compared to those displayed by regular civilians. We accomplished this by employing manipulated face stimuli that include either a police cap or a baseball cap to simulate the appearance of police officers and regular civilians.

Charles Darwin theorized that the original egocentric functions of facial expressions adapted to serve interpersonal purposes (Knutson, 1996). Facial expressions serve important functions in social interactions and have evolved to communicate emotions. While some expressions might have originated as sensory functions, such as widening the eyes (fear) to gather visual information (Susskind et al., 2008) or narrowing the eyes to enhance target discrimination (Lee et al., 2014), they likely co-evolved to serve interpersonal functions.

In humans, the expression of fear alerts individuals to potential threats (Susskind et al., 2008), while anger indicates impending danger (Wilkowski and Meier, 2010). These affective facial expressions act as powerful alarm signals, activating the amygdala and eliciting stronger responses to negative facial expressions than to scenes depicting fearful or threatening situations. Negative valence perception is also associated with increased heart rate (Jönsson and Sonnby-Borgström, 2003), which suggests that viewing scared or angry faces activates the sympathetic nervous system.

Facial expressions also play a crucial role in police-civilian encounters by providing important social cues that can help predict the other person’s behavior. One may make judgments about intent, trust, safety, or impending violence based on facial expressions, motivating the study of factors that influence facial perception in police-civilian encounters. While one study has explored how police officers’ interpretation of facial expressions can be influenced by workload and stress (Bélanger and Blanchette, 2022), and another studies the effect of smiling police (Simpson, 2021), there is an opportunity to study how attitudes toward the police conditions facial emotion perception of officers.

Incorporating an attitudinal component to the evaluation of police faces is key for advancement of law enforcement facial perception research. Police clothing represents one’s membership with law enforcement and may lead to the activation of any associated cognitions and emotions. The association between one’s social views of police and individuals wearing a uniform are likely to be interdependent and should be accounted for by police-centered facial perception studies.

Most police officers are White males in the United States which suggests predominant views of police are shaped around one sex and ethnic identity (Goodison, 2022). One can extend this research by considering whether attitudes toward police result in unique perceptions of police faces across sex and race/ethnicity. Studying this question is critical as it will identify whether attitudes toward police are global or attenuated by those who represent law enforcement.

We utilized a photo database (Conley et al., 2018) containing images of actors expressing various emotional expressions to investigate whether police officers’ facial expressions are perceived differently. Faces were selected to balance across gender and race/ethnicity and modified in three ways for our study: leaving them without headgear (condition 1), adding a baseball cap (condition 2), and adding a police hat (condition 3). We included the baseball cap as an additional control condition to account for the possibility that visual perception could be influenced by the presence of any type of headgear, rather than a specific type of headgear (i.e., the police hat). At the end of the session, participants completed a survey about their views of police.

Prior to conducting the study, we formulated two hypotheses: (H1) faces with police hats would be perceived more negatively compared to other headgear conditions, (H2) a correlation would exist between participants’ views of the police and how faces with police hats are perceived. Our findings support H2, but not H1 (see Discussion).

When considering all individuals, the valence rating for “angry faces” appears to be unaffected by the experimental condition (“No hat,” “Baseball Cap,” or “Police Hat”). However, notable differences between conditions were observed for “happy faces.” One plausible explanation for this finding is that happy faces are easily recognized compared to angry faces (D’Argembeau and Van der Linden, 2011), which aligns with the observations made in the RADIATE dataset (Conley et al., 2018). Enhanced recognition of happy faces allows for a higher level of perceptual granularity and may account for the influence of subtle variations, such as the presence of a hat or cap, in experimental conditions on valence ratings.

It is interesting to note that there were no significant differences in valence ratings between the “Baseball Cap” and “Police Hat” conditions for any of the emotional facial expression categories. This suggest that either the participants’ perception of the expression was not affected by these experimental conditions, or the perceptual shift toward more negative or positive perception of emotion were balanced among participants, and canceled each other out, resulting in the findings shown in Figure 2A. If the latter is true, it raises the question of whether participants’ attitudes toward law enforcement were related to their perceptual shifts. Specifically, whether they perceived faces with a “Police Hat” as more or less angry/happy than those with a “Baseball Cap” depended on their views of law enforcement. Interestingly, this was only observed for the “Angry Faces” category (Figure 3A) and not for “Neutral Faces” (Figure 3B) or “Happy Faces” (Figure 3C). Additionally, the correlation was stronger for angry male faces wearing a police hat compared to angry female faces (Table 1). Essentially, participants with negative views of law enforcement perceived an angry male face wearing a police hat as even angrier. These findings were also confirmed, although to a lesser extent, when comparing the “Police Hat” condition to the “no hat” control condition, with effects observed for both “Angry Faces” and “Neutral Faces” (Table 1). We also demonstrate these effects are not dependent of on the race/ethnicity of the image subject.

Our interpretation of police facial expressions may have a great impact in how we perceive police. A study evaluating the effects of facial expressions on perception of police officers for instance (Simpson, 2021) found that when police officers exhibit a smile, they are perceived as less aggressive and more accountable, approachable, competent, friendly, and respectful. Yet, in many police-civilian encounters, the police may not exhibit a friendly demeanor or interact with people who do not like police. Starting from a net negative view of police may inhibit de-escalation or conflict resolution techniques, increase the hostility of an encounter, or raise the risk of negative contact. These issues are crucial as perceived negativity increases the likelihood of one believing the police exhibit bias (Renauer and Covelli, 2011) during police-civilian encounters, especially for African American and Hispanic/Latine people. Further, negative views of police are stronger than positive views and curbs one’s satisfaction with law enforcement (Li et al., 2016). Starting at a deficit with respect to police hampers any kind of community policing or positive contact efforts. Unpacking the degree of negativity related to police face expression is critical for improving evidence-based community policing initiatives, encouraging civilian participation in crime prevention efforts, and gaining civilian compliance.

Our approach in this paper substantively advances prior facial perceptions of law enforcement research as it sought to replicate and extend past studies. The unique combination of behavioral and attitudinal research methods demonstrates the importance of using multiple methods for intriguing social questions. We also use multiple sets of faces balanced across emotion, sex, and ethnic identity to assess the sensitivity of uniform effects across those who may represent law enforcement. The control conditions used for the experimental conditions also allow one to determine if any observed effects are attributed to a particular type of clothing. In sum, we make several substantive contributions to literature.

Our study possesses several limitations that should be acknowledged. The participant pool consisted of college students, with a majority identifying as Hispanic/Latine, which may introduce bias into our findings. The overrepresentation of this demographic group, along with a skewed gender distribution favoring females, impacts the generalizability of our results. While these demographics have their significance, a more balanced representation would have been preferable. Furthermore, the study’s focus on Hispanic-centered research on police, while important due to its relative neglect, may limit broader applicability. A larger sample size could have allowed for a more comprehensive exploration of various factors, including age, socio-economic backgrounds, education levels, and mental health statuses, which may influence the relationships under investigation. In essence, our study serves as an important preliminary study, and we encourage additional research to address these limitations.

In future research, we will take significant steps to broaden the scope of our investigations. Given the heightened potential for volatility in interactions between police and individuals with mental health conditions such as depression, bipolar disorder, anxiety, or post-traumatic stress disorder (Kerr et al., 2010), it is crucial to expand our participant pool to include cohorts of individuals diagnosed with these mental health disorders. This expansion will enable us to delve deeper into the understanding of how mental illness impacts neural responses and physiological stress reactions triggered by the mere visual presence of law enforcement. Furthermore, we plan to adapt our research paradigm to encompass the perspectives of law enforcement officers during encounters with civilians. By considering the viewpoints of the police, we aim to study their opinions and examine their physiological changes in response to civilian stimuli. This approach will allow us to provide a comprehensive analysis of police-civilian interactions.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving humans were approved by Institutional Review Board of the California State University San Bernardino. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study. Written informed consent was obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article.

NB: Conceptualization, Formal analysis, Supervision, Visualization, Writing – original draft, Writing – review & editing. NM: Writing – review & editing. CB: Writing – review & editing. ZP: Conceptualization, Formal analysis, Investigation, Writing – original draft, Writing – review & editing.