Will Traumatic Stress Sharpen Your Memory-Or Sabotage It: What The Latest Findings Reveal

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How can an officer in a gunfight be looking at their sights and not see and respond instantly to a change in a subject’s behavior? Why couldn’t the officer see the other person? He has to be lying when he said he didn’t see the person drop the gun! Why can’t he tell us how many shots his partner fired? Didn’t he hear the commands that were shouted at him?

These are common remarks regarding an officer’s behavior and memory that can arise from anyone judging an officer’s behavior in a gunfight.

Law Enforcement has used the terms “tunnel vision” and “tunnel hearing” to explain how law enforcement officers process information under high stress conditions – from gunfights and high speed pursuits to tough physical encounters. These terms are used to explain why officers were able to clearly explain some elements of the encounter while literally being blind to other apparently obvious elements. Although these terms have occasionally raised the criticism of apologizing for ineptness or deceit by the officer, most law enforcement investigators, officials, the court system and civilians are aware of what these terms mean and tend to give them some credibility.


What is generally unknown and needs to be understood — is how and why these phenomenon work, how common they are, and what a huge body of psychological research and experience under-girds them. For instance officers and investigators appear not to know that tunnel vision and tunnel hearing can be mutually exclusive. If an officer in a high stress situation is strongly visually focused on something and experiencing “tunnel vision” they cannot simultaneously be experiencing “tunnel hearing”.

They can of course have a “soft focus” across all the senses or even within the same sense, for example visually scanning a scene, but once the officer’s attention is strongly directed to one event in a sensory system, they cannot simultaneously process information either in the same sensory system or in another sensory system. They may experience them in sequence, for instance shift from “tunnel vision” to “tunnel hearing” and then back again to “tunnel vision”, but they can’t simultaneously do both. Officers may believe they can do both because they may fill in the blanks about what has occurred. Given time, and based on the context and change in what the officer perceives, they link events and “fill in the blanks” and thus create a memory for events rather than “recording” an actual memory of the event. For instance, if something occurred in the visual sense while the officer’s attention was diverted for even a fraction of a second, the officer would be incapable of recalling what happened during that period and may not even believe something occurred while their attention was distracted, despite clear and factual forensic evidence to the opposite.

Another fascinating but little known fact is that thoughts can have the same tunneling effect as events. An officer who is psychologically recoiling when confronted with an immediate and direct threat to their life could be “attentionally tunneling” into their own thoughts and can be blind to anything that is going on outside of their own head. Or, an officer who is desperately trying to figure out how to unjam their gun in the middle of a close gunfight is also attentionally tunneled, except it is to solving a problem, instead of the movement or action of the threat that may be simultaneously occurring. They are still incapable of seeing what they are not focused on at that moment.

Despite the fact that law enforcement has chiefly chosen to use these terms in reference to high stress encounters, and some individuals erroneously believe that high levels of anger and/or fear are necessary for “tunnel vision” and “tunnel hearing” to occur, the reality is that all human beings are experiencing these phenomenon at some level and to some degree all of the time. Anger and fear of course will generate these phenomena but attentional tunneling actually occurs at any emotional level. All that is necessary is for the individual to begin to concentrate on something and the phenomenon starts to appear. “Inattentional blindness” is the name for the process of rejecting information coming into a sensory system because of a focus on something that is more important at that particular point in time.

Both “tunnel vision and hearing” are part of how human beings are able to pay attention in a world that bombards us with stimuli and our own mind preoccupies us with our own thoughts. Without an ability to concentrate and focus we would be flooded with information and be functioning as if we had an attention deficit disorder. The fundamental principle is that we need to select and focus our attention to whatever is important to us – including our own thoughts, and the higher the level of stress the greater is our need to focus to get important information.

Also the greater is the need to exclude the information that is not important. Functionally, as long as the stress level is low enough, we can have a “soft” focus across many senses and or thoughts. This is how we can multi-task, particularly with routine non-stressful activities. Once we begin to target on something we quickly loose the ability to acquire and process anything other than what we are focused on, until we change our focus. This focus does not have to include any emotional component. The tennis player, the chess player or the student focusing on completing an assignment all can demonstrate amazing powers of concentration that include significant “tunnel vision” and “tunnel hearing” and a significant blindness to anything other than that on which they are concentrating. Has the reader ever put on a CD to play and then been so preoccupied on a task they didn’t hear a single song?

In baseball, it takes 54/100ths of a second for a fastball traveling at 90 mph to travel from the pitcher’s mound to home plate. A baseball player who is focused on hitting the ball, whether under the stress of competition or just during practice, is usually so attentionally limited by their focus on the grip of the ball in the pitcher’s hand, the motion of the pitcher’s arm and the initial path of the ball, that during that half a second – if they truly are focused – they would not be able to inform us about anything else going on in the playing field, including the feeling of the bat in their own hand. This is usually not important for them and no one is concerned about this but when the same phenomenon occurs to an officer in a gunfight it becomes of major significance. Those concerned with evaluating an officer’s performance had better understand how and why this process occurs if they are going to objectively judge that officer.


The process of selection and attention has always been understood by psychologists to be a cognitive or brain process issue and not a sensory process. For instance, science tells us the eye appears to be continually reporting all the sensations to the brain, the brain selects from the sense what it needs and actively rejects or suppresses the rest of the information (leading to the impression of tunneling in that particular sense). But the brain is at work doing this – not the eye. Therefore the name “tunnel vision” is very descriptive, but misleading. Psychologists refer to this “focus” as “selective attention”. The process of rejecting information is termed “inattentional blindness”. Psychologist have been able to demonstrate in the lab, under non-stress conditions, that you can be looking directly at something and literally be blind to it if you are not attentionally focused on it.

The reader will note that “selective attention” does not make any reference to any specific sense such as vision or hearing and the reason is that attention can be directed to anywhere in the person’s thoughts, body or to any sense. Under intense focus, we are able to report on selected information in one sense or a thought but are “blind” to the information from other senses or thoughts.

This process of selecting some information and rejecting or being blind to others is a normal and constant feature of human performance at all levels. The reader may note that their attention to this article has inattentionally blinded them to the feeling of their clothes on their body or the chair they are sitting on. Even focusing on a thought in your head has a significant impairing effect on processing sensory information. In Force Science News #54, in which we reported on the limitations of emotionally charged cell phone conversations, we noted that Dr. Paul Atchley and other researchers found that when drivers were focused on just emotional words spoken into their cell phones they were so oblivious to information outside their head and their vehicle that they couldn’t tell the difference between a dumpster by the side of the road or a child starting to run out in front of them.

The reader may be aware of times when they were driving home, intently focused on some deep personal issue, and were surprised to arrive at home unaware of seeing or remembering any turn they made or light they stopped at. This could only occur with a practiced behavior on a very familiar course of travel but it can and does occur under conditions of intense concentration, fatigue.

This brain process of focusing or “tunneling” (selective attention and inattentional blindness) holds true for all humans, under most conditions, but especially for officers engaged in emotionally intense situations, such as pursuit driving, fighting, or shooting.


A further fact is that “attention” can contain elements of both breadth and depth and the focus could be on points both inside and outside the person. “Selective attention” when directed outside the person could be directed to any location in physical space. For example, a person in a forest could select to visually focus in general on the forest, any tree in the forest, near or far, left or right. A focus or attention could also be internal and so the person could then focus internally and narrowly on their feeling of being in the forest. They could also focus internally and broadly on the sense of movement through the forest.

Understanding and being able to explain officer performance in a high stress encounter needs a knowledge base of much more than just “tunnel vision” and “tunnel hearing.” We really to get much more sophisticated in our understanding of human performance and use of that information so that training, investigation and explanations to the public can all be improved.

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