Be forewarned. This isn’t a politics, firearms, or current events site. It’s dedicated to our mission of providing insightful, scientifically grounded analysis for use and application by professional trainers. If you’re looking at this issue through a political or some other biased lens, you’re probably not going to like what’s written here – regardless of what side of the relevant current events dice you happen to be sitting on.

The intent of this article is to apply our research into brain-based force science and training methodology to the concept of implicit bias. The objective is to understand, given the tools and information available to us, what this term means, whether or not it defines a real, viable concept, and, if so, how it applies to the job of professional trainers.

The term itself can be somewhat controversial. To some people it sounds like blathering social psychobabble, intended to deflect conversation away from the “real” issues. However, our research into brain science as applied to use-of-force and other related training suggests that, regardless of any intent or application in socio-political circles, implicit bias isn’t a joke. Far from it. It’s a real thing, with real operational consequences.


First thing’s first. What is implicit bias?

Let’s break down the phrase. It contains two words, implicit, and bias.  

Bias has a number of dictionary definitions. According to Merriam-Webster, they include:

a : bent, tendency

b : an inclination of temperament or outlook; especially : a personal and sometimes unreasoned judgment : prejudice

c : an instance of such prejudice

d (1) : deviation of the expected value of a statistical estimate from the quantity it estimates (2) : systematic error introduced into sampling or testing by selecting or encouraging one outcome or answer over others

Implicit is a reference to an educational psychology based model of memory in which the brain contains three memory systems. They are the explicit memory system, the implicit memory system, and the short-term, or working, memory system.  

The implicit / explicit brain model is older than the procedural / declarative model that is currently used by most brain specialists and that we use exclusively in our recent book Building Shooters. There are some nuanced differences between the two models that are, frankly, outside the scope of this discussion. The procedural / declarative model is proving to more accurately match the results of ongoing neuroscience research, and it conforms with the terminologies applied throughout the bulk of our research. Therefore, for our purposes here, we will replace the term “implicit” with its parallel term in the newer model, that is “procedural.”

The basic model of human memory includes a short-term memory system, through which all new input must pass, and two redundant, yet functionally separate long-term memory storage systems. These systems are called procedural and declarative, respectively. Short-term memory can be thought of like a computer’s RAM disc space. It is a small, finite, temporary storage space and it doesn’t permanently store anything. Procedural memory is accessed unconsciously, without thought or intent. Declarative memory requires a conscious act of recall; you must intentionally retrieve the information.

The vast majority of the input human beings receive is filtered out and discarded before it ever reaches short-term memory. Out of the small percentage of input that actually makes it into short-term memory, only a tiny percentage is ever actually retained. Retention requires that the information be transferred into at least one of the long-term memory systems.  

When we put these terms together into procedural (implicit) bias, we get an unintentionally, unconsciously accessed tendency, outlook, prejudice, judgment, or statistical deviation – that has been coded into a specific part of the brain – procedural memory.

It is also of note, that procedural memory is the ONLY memory system that can be reliably accessed by the brain during high levels of stress, such as use-of-force situations and other critical incidents. When the stress level goes up, whatever is in procedural memory is what’s going to come out. The content of the other memory systems during critical incidents is largely irrelevant.

Research and Analysis

A significant component of the current socio-political discussion centers around the concept that police officers in particular have a bias (implicit bias) against specific demographics – black men in particular – a bias that leads to disparate treatment, in-turn leading to unjustified use-of-force.  

If we ignore the sociology and the politics and focus on the data, the following picture emerges. First, black men – viewed as a demographic – is by far the most dangerous group in the United States. This is an overwhelming statistical fact. For example, the demographic comprises about 6.5% of the population yet is responsible for about half of the homicide. By definition, this is a bias – a statistical deviation from the expected value.  

However, this is not, and cannot explain, a procedural bias. If applied to the brain, it would be more accurately described as a declarative (or explicit) bias. In other words, this is a statistically based bias that exists in consciously recalled memory and that must be consciously accessed and applied. Furthermore, this type of bias is unlikely to be accessible to the brain when a decision involving the application of force, especially deadly force, is made in the field. While our research indicates that declarative memories may in-fact influence the formation and development of procedural memories, it is also clear that they are not the same thing.

When we talk about procedural memory development that relates to tactical operations (to include use-of-force decision making) our research identified five distinct types of neural networks that apply. These are: physical motor skills, stimulus recognition and response, contextual recognition and response, associative judgment, and skill/context modification and transfer. Furthermore, we identified a number of factors which contribute to the development of these neural networks specifically within the procedural memory system. These factors include repetition, observation, emotional connection (specifically including fear), stress, and chaos.  

When we apply this information to the operational environment of a police officer, the neurological impact of the job itself becomes obvious, especially for officers who work in violent precincts containing a majority population of any single demographic. Rarely are the police called to respond to a birthday party, wedding celebration, graduation, or other happy occasion. People call the police when something is wrong, especially when there’s a violent crime.  

Police officers respond, with extensive repetition, to situations in which they observe and experience violent criminal activity, often with the potential to cause them or others serious injury and/or death. This potential causes fear and stress, emotions which equate neurologically to the release of chemical compounds into the brain tissue, compounds which can fundamentally alter the performance of the brain and rapidly form procedural memories – especially associative connections relating emotions and actions to specific stimuli and contexts. In these chaotic, emotion-laden environments, police repeatedly apply physical and cognitive skills that correspond to varying levels of the force continuum and, while application of deadly force is rare, the decision-making process involving the tools for deadly force application can be a daily occurrence. 

The operational environment of police officers, especially those who work in precincts with high levels of violent crime, is a literal factory for the development of procedural memory. It is an environment laden with repetition, stress, fear, emotion, and chaos which requires the continuous and repeated application of virtually every neural pattern, cognitive and physical skill involved in use-of-force decision making – and it contains unique patterns of demographic indicators that often correlate strongly to both the frequent application of these neural networks and high levels of chemical saturation of brain tissue. When the operational environment includes stimuli or contexts (to include location, patterns of behavior, dress, speech patterns, demographic indicators etc.) that either correlate into a pattern or correspond with a highly traumatic event, our research suggests that it is a biological certainty that procedurally consolidated memories that are based on those patterns or specific stimuli and contexts will be formed. 

In other words, based on our research to date, it is neurologically impossible for police officers who work in violent precincts where the preponderance of the crime and violence is committed by any specific demographic, NOT to develop a procedurally consolidated bias. Other social and cultural factors may or may not be relevant; these are beyond the scope of our research. It is however a virtual certainty that procedurally consolidated contexts and stimuli related to decision making, some of which are certain to be dependent on local geography and demographic indicators, exist. It is also a virtual certainty that these procedural memories are created “on the job” purely through operational activity within the confines of the operating environment.  

What does it mean?

If we accept this interpretive application of our research – that procedural bias with respect to certain demographics does exist – and that it is a biologically unavoidable result of working within certain, existing operating environments – what does this mean?

As trainers, our job is to positively influence operational outcomes through preparation. In order to do this, we have to understand the operational environment and the factors that influence it. Therefore, let us assume at this point, for discussion’s sake, that procedural bias does exist as described. What then does this mean, operationally?  

First, this means that operational decision making, especially during high stress situations, will be influenced – biased if you will – by stimuli and contexts that form patterns or that have been closely associated with trauma on an individual level, within the operating environment.

Second, this means that these same neurological effects also can impact the citizens who live and work in that same environment, with equal, if not greater, potency.

What can be done?

There does not appear to be an easy answer here, particularly given the political and social aspects of the issue. We are not going to make commentary or recommendations on law enforcement strategy or specific tactics here; however, specifically with respect to training approaches and methods, we believe that there are at least a few fundamental changes that can improve understanding, performance, and outcomes.

First, both law enforcement officers and the general public should be educated, with declarative knowledge, about what procedural bias is – really is – and what causes it. And agencies should stop apologizing for it. This is especially true when these biases contribute to decision-making that improves both officer safety and public safety. Asking a police officer not to develop a procedurally consolidated set of biases related to that officer’s operating environment, then blaming them for it when they do, is akin to asking a construction worker to rip out asbestos walls without a respirator and then blaming them for getting mesothelioma. It makes no sense and helps nobody. Furthermore, acknowledgement of, as opposed to denial of, the procedural consolidation of stimuli and contexts that are present in the operating environment, the potential impacts this has in the field, and its causes, may provide new opportunities and avenues for training development, tactical development, and community involvement outside of incident response.

Administrators, trainers, politicians, and activists should not expect that declarative (classroom) training will have much, if any, impact with respect to affecting operational decision-making in use-of-force situations. Furthermore, each of these groups should strive to put aside talking points and political expediency in favor of publicly acknowledged, grounded, and realistic objectives and expectations. Declarative knowledge and policy changes may have the potential to impact the lead-up to use-of-force situations. However, since the procedural memory system is the dominant system when stress levels elevate – sometimes to the complete exclusion of other memory systems – these types of standard “training” activities are unlikely to impact use-of-force decision-making in the field.

However, law enforcement does have the capability to positively impact use-of-force decision making and the skills that relate to the application of force through improvements in both its standard entry-level and in-service training programs. We discuss the limitations of the existing paradigm at length in Building Shooters, the full scope of which is beyond the purpose of this article. However, integrating regular performance of interleaved (chaotic) training that is designed to directly correspond to the contexts and stimuli inherent to each individual operating environment has the biggest potential to improve both operational decision-making and clinical skill performance for law enforcement professionals.


In conclusion, our research into the brain science around use-of-force and related training indicates that implicit bias does exist, particularly among law enforcement professionals. It further indicates that this bias is an unavoidable byproduct of the environment that law enforcement works in and the job that law enforcement does. Professional trainers would be well served to educate their students about the science and meaning behind the formation of stimulus and contextually based biases, and to shift the focus of their training programs from the repetitive performance of clinical skills themselves to the repetitive performance of the decision making processes that result in applications of force.

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"Easily one of the more important books of our time when it comes to preparing police, military and armed civilians for armed lethal combat."
-Kenneth Murray
Author, Training at the Speed of Life
Co-Founder of Simunition