- Under high levels of stress, people may experience "tunnel vision," tending to ignore things on the periphery of their awareness.
- The human tendency toward tunnel vision under stress may have been valuable in the ancient world but it can prove dangerously limiting today.
- Awareness of this tendency can keep people out of trouble in stressful environments, in both the perceptual and cognitive realms.
In this Forensic View, we continue our series on major cognitive elements of stress. In this post, we’ll examine one of the most important aspects of high-stress environments: tunnel vision.
Tunnel vision occurs when we focus on the central aspects of a given situation at the expense of attention to the periphery; we focus on the core of the situation, to the relative exclusion of the surrounding details.
This can kill you.
Law enforcement officers and tunnel vision
In an important study of law enforcement officers, Klinger (2004) found that tunnel vision is one of the most frequently experienced aspects of high-stress environments. Generally, in any given situation, we may focus on the central characteristics of that situation in the belief that we’ve identified the core, the most important elements, of whatever’s going on. The problem is that we may be wrong.
Many law enforcement and military personnel have been shot not by the armed assailant immediately before them, the subject of their central focus, but by an individual on their periphery. We might think that the given soldier or officer simply didn’t see the peripheral assailant, but this is frequently incorrect; often the peripheral threat is seen, but somehow not encoded as a subject for action.
This occurs in actual cases, but also in realistic training—the present writer has seen experienced officers, charging on foot toward the scene of a mock crime, literally kicking mock improvised explosive devices (IEDs) out of their way to do so. Others have been so focused on the apprehension of a mock suspect in a building that they fail to notice training ammunition, fired by an “adversary” on their periphery, splatting into the wall of the building within a few feet of their heads (Sharps, 2022). An excellent study by Hope et al. (2012) found that officers, in a high state of arousal from the stress of a hard physical workout, might not even notice people, in plain sight, as the officers ran toward a mock “crime scene.” This is an effect I personally have seen repeatedly in less-controlled training situations.
Civilians and tunnel vision
Civilians don’t do any better. In my research, civilian “eyewitnesses” observed crime scenes. Eye-tracking data demonstrated that all had “seen” a mock IED placed in the periphery of their fields of view. However, only about 1% reported it- all had seen it, but it had registered in the minds of only about one in a hundred (Sharps, 2022).
Tunnel vision is very real, and it gets worse the more aroused or upset we become.
How could this be? How could the human species have survived the rigors of the ancient world, in which we evolved, if we tend to get killed by the threat on the left or the right while we’re battling the threat out front?
Evolutionary ancestry and tunnel vision
As discussed in previous Forensic Views (e.g., 4/24/20) and elsewhere (Sharps, 2022), much of our present behavior was shaped by our evolutionary ancestry. It is very likely that the necessities of hunting generally preceded the human experiences of warfare and crime. Now, unless one is hunting a large carnivore, the danger to the modern hunter is relatively limited; shooting deer with a rifle at hundred-yard distances results in far more venison than casualties.
However, the same deer at a range of four or five feet was a very different animal, especially when the hunter’s weapon was a spear with a very limited magazine capacity of one. For one thing, deer can kick you to death. Also, their antlers are exceedingly pointy. Therefore, if ancient hunters were within antler-range of a deer, they needed to focus fairly exclusively on the pointy animal before them—on the center of the situation, not the periphery.
Granted, there may have been other peripheral deer in the hunter’s field of view; but an important attribute of deer is that they do not form gangs. There are no affiliated deer, and beyond antlers and hooves, they are unarmed. They aren’t particularly loyal, either; the deer on the periphery are typically thundering away across the plains even as the hunter spears their compatriot directly out front, without a single thought of deerish vengeance.
Humans, however, frequently take revenge from the periphery or anywhere else, for that matter. Yet we still tend not to focus on peripheral threats. In effect, under threat, your brain thinks it’s hunting a deer.
Adjusting to today's peripheral threat
Of course, there were ancestral hunting and other situations in which peripheral threats were important; but perhaps not as many as in the modern world, in which crime and warfare have been refined nearly to exact sciences. Today, the prospect of peripheral threat is frequently high, in many different situations.
The good news is that we can train ourselves, and we can be trained, to be more responsive to peripheral threat. For example, relatively simple cognitive training can render ordinary people much better at spotting IEDs placed on the periphery of crime situations (e.g., Sharps, 2022). There are many other examples.
But the trick is to be aware that we tend to focus only on the core of the given situation, and to force ourselves, actively, to consider what’s going on around that core. If you’re focused on cleaning your rain gutters, it’s worthwhile to spend a few peripheral moments checking your ladder. When cutting a workpiece on a table saw, it’s a good idea to check the positions of your thumbs on the periphery as well as the position of the wood in the center. And a central focus on making your spouse see your point of view might best be broadened to take in how your words will be received; spousal response may be peripheral to you, at the moment, but dramatically more central to your spouse and to the future of your marriage.
Some peripheral hazards are deadly. Others are more prosaic, but still of great importance. Awareness of, and prior preparation for, our tendencies toward tunnel vision may prevent a variety of unpleasant or even catastrophic consequences in law enforcement and in everyday life.
Hope, L., Lewinski, W., Dixon, J., Blocksidge, D., & Gabbert, F. (2012). Witnesses in action: The effect of physical exertion on recall and recognition. Psychological Science, 23, 386‐390.
Klinger, D. (2004). Into the kill zone: A cop’s eye view of deadly force. San Francisco: Josey‐Bass.
Sharps, M.J. (2022). Processing Under Pressure: Stress, Memory, and Decision-Making in Law Enforcement (3rd ed.). Flushing, NY: Looseleaf Law.