PDF Summary:Left of Bang, by Patrick Van Horne and Jason A. Riley

In military and law enforcement training, most preparation focuses on reacting to attacks after they happen. But in Left of Bang, authors Patrick Van Horne and Jason A. Riley argue that the key to survival lies in detecting threats before they materialize. Drawing from the Marine Corps' Combat Hunter program, they explain how to identify pre-attack indicators through careful observation of human behavior and environmental patterns.

Van Horne and Riley introduce six observational domains—including body language, use of space, and symbolic imagery—that help filter relevant information and spot anomalies that signal potential threats. They explain how to establish behavioral baselines, recognize when something deviates from normal, and make rapid decisions under pressure. While developed for combat situations, their framework for proactive threat detection applies to anyone seeking to improve their situational awareness and ability to identify dangers before they escalate.

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(Shortform note: The color-coded terminology used here is a common way to describe different types of military forces and their interactions. In this context, “blue” refers to coalition forces, while “green” refers to local security forces. The “X-on-Y” formula simply indicates which group is acting against the other.)

Sometimes, attacks against U.S. personnel by members of the military, contractors, or government employees occur due to intentional, malevolent motives. The authors note that the risk of "green-on-blue" assaults has significantly increased in recent years. This increase is mainly because of the greater danger that comes from more joint operations like patrols, and because the coalition has taken on more mentoring roles. More interpersonal interaction results in a greater risk. The reasons for these attacks primarily fit into two classifications: friction caused by cultural disparities and interpersonal disputes, and insurgent groups' infiltration and influence. Most of these attacks occur due to personal grievances.

(Shortform note: Before the rise in "green-on-blue" assaults, researchers had already identified two main types of insider threats: those driven by personal grievances and those motivated by ideological or organizational allegiance. This framework was later adapted to understand insider violence in military contexts. In 2011, Greitzer and Hohimer published a study on insider threats, identifying two primary categories: disgruntled employees and ideologically motivated individuals. Disgruntled employees often act out of personal grievances, such as perceived unfair treatment or lack of recognition. Ideologically motivated insiders, on the other hand, are driven by allegiance to external groups or causes, making them susceptible to infiltration and influence by hostile organizations.)

The danger of these attacks will persist as long as U.S. Marines and other military personnel collaborate with host-nation security forces. The essential action is to adopt measures that will reduce the risk of such incidents and prepare our security forces to prevent them.

(Shortform note: One measure that could reduce the danger of these attacks is the creation of a joint insider-threat fusion cell. This cell would aggregate behavioral, administrative, and intelligence data on host-nation personnel to provide commanders with early-warning alerts about potential attackers.)

Next, the authors discuss observational domains and signals, as well as decision-making and action.

Observational Domains & Indicators

According to Riley and Van Horne, kinesics, which analyzes body language, is crucial for profiling in combat. It helps identify those who seem out of place and predict their behavior based on subtle behavioral cues. Combat profiling emphasizes clusters of behaviors or numerous signals instead of individual gestures. These groups are contrasted with the baseline to spot anomalies. The more signs that suggest the same outcome, the more precisely combat profilers can predict someone's feelings and behaviors. To verify a grouping, you must see a minimum of three signs. Clusters reflect how someone perceives dangers and their readiness to handle them.

(Shortform note: While some psychologists agree that you should look for clusters of behaviors, they don’t agree on the minimum number of signs you need to see before you can trust your interpretation. For example, some deception researchers argue that there’s no universal rule for how many signs you need to see before you can trust your interpretation. In one study, researchers found that the number of signs needed to make a judgment varied depending on the context and the specific behaviors being observed.)

Next, Van Horne and Riley discuss the six observational domains, as well as domain-specific indicators and interpretation.

The Six Observational Domains

Van Horne and Riley explain that the six domains help identify threats by focusing on key human behaviors. These areas are:

• Kinesics: nonverbal communication through physical movement
• Biometrics: involuntary biological responses to stress
• Proxemics: how individuals utilize space and distance
• Geographics: how people relate to their surroundings
• Iconography: the symbols people use to communicate beliefs and affiliations
• Atmospherics: the overall ambiance and conduct of a place

The domains help filter out irrelevant information, allowing you to focus on the most important details of human behavior. They also help create a standard of typical actions and identify irregularities that might indicate a threat.

The Origins of the Six Domains

The six domains are a synthesis of earlier research traditions. For example, in Nonverbal Communication, Judee K. Burgoon, Laura K. Guerrero, and Kory Floyd argue that nonverbal communication is best understood as a coordinated, multichannel system in which individuals simultaneously use the body (for example, face, eyes, posture, movement, touch), the voice, spatial arrangements and territorial behavior, physical environments and artifacts, and even physiological responses associated with arousal and emotion to create, regulate, and interpret social meaning. This approach integrates insights from kinesics, proxemics, environmental psychology, semiotics, and physiological psychology, emphasizing that behavior, context, and biology must be analyzed together rather than as separate, unrelated phenomena.

Domain-Specific Indicators & Interpretation

The authors explain that proxemic pulls and pushes can signify possible dangers or important interactions. A proxemic attraction happens when people are drawn to someone, another group, an object, or a location. The inverse is distancing from another individual, location, or thing. There are various causes of proxemic pulls: interest, a need that can be fulfilled, an existing relationship, or attraction and curiosity. They occur when a person perceives no danger, so their body isn't primed for fight or flight.

(Shortform note: In The Hidden Dimension, Edward T. Hall explains that people are constantly moving and adjusting their positions in response to their goals and the environment. This movement creates a dynamic pattern of density and flow, with some areas becoming more crowded and others more sparse. These patterns can reveal where people are focusing their attention or where potential threats might be located.)

Proxemic pulls matter to combat profilers since they direct the profiler's focus to particular interactions that offer understanding of the group being watched. They indicate that someone or something is different from the norm. Suicide bombers look for proxemic-pull centers, such as markets or religious sites, where the highest number of people are. Enemy forces also try to leverage proxemic attraction to lure Americans into ambush locations. They might accomplish this by either examining our tactics, routines, and patterns to anticipate our future locations or by acting to lure American forces to places where they're positioned.

(Shortform note: The concept of proxemic pulls is rooted in the broader field of proxemics, a term coined by anthropologist Edward T. Hall in the 1960s. Proxemics studies how people use space in communication and social interactions, revealing that different cultures have distinct norms regarding personal space and physical distance. Hall's research showed that people within the same culture share an unspoken understanding of which spaces are considered public, social, personal, or intimate. This shared understanding makes proxemic pulls and proxemic-pull centers predictable, as people naturally gravitate toward certain spaces based on cultural norms.)

Insurgents might employ various strategies to attract attention: they could instigate civil unrest to compel reserve forces to mobilize, plant a fake IED to make explosive specialists intervene, or attack a patrol and then run away to provoke pursuit. By comprehending the adversary's strategy for proxemic pulls, patrol leaders can cleverly strategize to predict where the enemy intends to lead the patrol, and then they can evade the opponent rather than being caught in an ambush. In opposition to the proxemic pull, a proxemic push happens when a person wants to escape an actual or possible danger, or due to anxiety or doubt caused by insufficient information. The choice to distance oneself from an apparent threat typically involves a "flight" aspect.

The Limits of Intuitive Expertise

If insurgents know that patrols are using proxemic pulls and pushes to anticipate their plans, they could use this knowledge to their advantage. For example, they could stage a crowd to create a proxemic pull, luring the patrol into an ambush. They could also create a proxemic push by making it seem like there’s a threat in one direction, causing the patrol to move in the opposite direction, which could also be a trap. Kahneman and Klein argue that reliable intuitive expertise arises only in what they call “high-validity” environments, where there are stable, learnable relationships between cues and outcomes and where decision makers receive timely, accurate feedback over many learning trials. In contrast, in “low-validity” environments—those that are noisy, unstable, or deliberately deceptive—people may still feel strong intuitive confidence, but that confidence is not a dependable indicator of actual judgment accuracy.

Next, the authors discuss iconography. This refers to visual language or imagery that communicates the existence, convictions, or affiliations of people or collectives. Iconography can be categorized into two areas: symbols on people and symbols within geographic settings. Visual symbolism isn't directly connected to human behavior. It doesn't result from the autonomic processes or limbic system. It's simple to hide or alter personal iconography, like covering tattoos or altering clothing. However, iconography can help combat profilers boost their situational awareness. By examining and interpreting the symbols present in a human context, combat profilers can discern an individual or group's beliefs, as well as their affiliations, allies, and enemies.

(Shortform note: In Codes of the Underworld, Diego Gambetta explores how iconography functions as a form of communication within high-risk groups. He argues that in environments of chronic distrust, individuals use visual symbols to convey otherwise hidden information about their beliefs and affiliations. Gambetta explains that these symbols—whether tattoos, scars, or specific styles of dress—serve as relatively trustworthy signals because they are costly to adopt and maintain. The risk, irreversibility, or expense associated with these symbols makes them difficult for outsiders to fake, thereby enhancing their credibility as indicators of group membership or commitment.)

By examining iconography, those who profile for combat can discern the priorities and influences of individuals and groups in a region. Combat profilers can discern the direction and trajectory of political, societal, or military events by tracking how iconography evolves over time. In geographic areas, iconography can reveal the creators' motives or beliefs, if local groups are in conflict, and the relationship between residents and those who created the iconography. The symbols that people exhibit can also convey key insights. To start, we can discover the particular causes or issues a person supports or opposes, especially if the symbols express disapproval of something. Second, we can determine a person's associations. Third, we can determine someone's status or how they perceive it. Combat profilers should note three primary iconography categories: public iconography, like graffiti, tattoos, and attire or related objects.

The Semiotic Roots of Iconography

The authors' approach to iconography draws on a long tradition of semiotic analysis, which treats visual symbols as a kind of language. As an online encyclopedia article explains, art historians have long used iconography to decode the meaning of recurring motifs in paintings, sculptures, and other artifacts. By comparing how specific symbols appear across different works and historical periods, they infer the cultural codes and values embedded in those images. This method assumes that visual signs, like words, carry meaning that can be deciphered through careful observation and contextual analysis. The authors' focus on how iconography evolves over time echoes this approach, suggesting that changes in visual symbols reflect shifts in underlying social and political dynamics.

Analysis, Decision-Making & Action

Van Horne and Riley explain that profiling for combat helps rapidly and precisely determine what to do in threatening circumstances. It's a way to decide in complicated and turbulent settings, where there's no ideal answer, choices must be swift and made with minimal data, and those deciding must heavily rely on intuition. Decision-making is straightforward: create a baseline, spot irregularities, choose, and take action. The crucial element in decision-making is timing—the combat profiling guideline states that three anomalies are sufficient for a decision.

(Shortform note: In Gut Feelings, Gerd Gigerenzer discusses the effectiveness of “fast-and-frugal” decision rules, which are simple heuristics that ignore most available information. He argues that these rules can be surprisingly effective, especially in environments where the cost of missing a real danger is much higher than the cost of reacting to a false alarm. In such situations, a good rule is one that minimizes the more costly error, even if it means accepting more false alarms. This perspective supports the idea that a guideline like “three anomalies are sufficient for a decision” can be effective in high-stakes environments.)

A combat profiler might make three choices, in the sequence of Kill, Capture, or Contact. In an environment that could be hostile, combat profilers should first decide to kill or get ready to do so. If someone isn't aggressive, doesn't show any hostile behavior, or signal that they're a direct threat, the combat profiler shifts to the capture decision. If the person doesn't display signs of possibly being a threat or if they don't seem to hold significant intelligence importance, the profiler advances to the final option: contact. If the person exhibits additional signs, the profiler might decide to reverse the decision and go with capture or kill if needed.

The Risk of Moral Injury

In Soul Repair, Rita Nakashima Brock and Gabriella Lettini argue that military training that encourages soldiers to override their natural reluctance to kill can lead to moral injury. Moral injury is the psychological and spiritual harm that occurs when individuals participate in, witness, or fail to prevent actions that violate their deeply held moral beliefs. This injury can manifest as guilt, shame, loss of meaning, and a shattered sense of being a good and trustworthy person. Even when actions are legally sanctioned or deemed necessary in combat, the internal conflict between one's actions and moral values can cause lasting psychological damage.

Van Horne and Riley explain that in combat profiling, making decisions involves assessing threats and choosing between taking a life, apprehending, or making contact. The first decision, kill, includes taking a life, as well as the mental resolve and physical readiness to do so. The second decision, capture, involves either restraining the targeted individual through physical force or ensuring they cannot leave the area. The final decision, contact, requires physically approaching the person for questioning or maintaining concentrated observation.

(Shortform note: In policing research, Alpert and Dunham describe decisions similar to taking a life, apprehending, or making contact as points along a “use-of-force continuum.” This model organizes options from verbal engagement to deadly force, helping officers make decisions within legal and ethical boundaries. The continuum provides a structured approach to escalating force, ensuring that each action is justified and proportionate to the threat. This framework is crucial for maintaining accountability and protecting both officers and civilians during high-stress encounters.)

The initial choice in the process is the most extreme, because in combat scenarios, being unprepared for maximum violence could be dangerous. In dangerous circumstances, it’s far easier to de-escalate from a choice to kill than to escalate to that decision. If the threat is both immediate and serious, switching from contact to capture to lethal action wastes precious time. Combat profilers ought to first evaluate whether they need to make the gravest decision—kill—and then proceed to the next, less grave, decision: capture.

(Shortform note: In some contexts, this approach would be impermissible. For example, the United Nations Office of the High Commissioner for Human Rights (OHCHR) states that police officers should only use deadly force as a last resort to protect life. In this context, it would be inappropriate to begin a threat assessment with the option to take a life.)