Understanding Stress – Part 5: Tunnel Vision

Welcome to Part 5 of my discussion on stress. In the last segment I talked about the positive and negative impacts of hyper vigilance and its impact on situational awareness.

While stress-released hormones increase arousal of the senses, the brain struggles to process all the information coming in. If you try to process the meaning of all the audible and visual inputs, you may find yourself on the fast-track overload.

In this segment, I’m going to discuss tunnel vision. When I was a new recruit, I vividly remember my training officer telling us ‘don’t get tunnel vision.’ He said it with such conviction that I knew it was important. So I wrote it down. But he never really told us what it was, how we get it and most importantly, how to avoid it. Let’s explore the concept of tunnel vision.

Tunneled vision

Early on in my journey into neuroscience I learned something about tunneled vision. It is a mislabeled term. While I have often heard the term used throughout my tenure in public safety – and having used it many times in my early years as an instructor, I never realized that the term tunnel vision does not accurately reflect what happens under stress. It’s a little more complex than I had realized.

 

 

Tunneled senses

Tunneled senses more accurately depicts the results of stress. All your senses can become tunneled when you are stressed. For vision, it means your visual attention can be focused on one small geographic area of an emergency scene or one task being performed at a scene and you miss seeing things in your periphery. For hearing, it means your audible attention can be focused on one source of sound, like a person talking to you face-to-face or text messages on your phone, or a siren of an approaching engine.

When you are suffering from tunneled senses your situational awareness is vulnerable because you are likely to miss important clues and cues. Many things happen in the peripheral vision that will be lost when vision is tunneled. When hearing is tunneled, you can miss hearing other things happening around you. The fixation on a single conversation or a single sound prevents you from hearing other things.

It gets worse

Researchers at Johns Hopkins University ran a series of audible and visual tests on human subjects, measuring the loss of acuity while engaging them in activities designed to narrow attention. The results were a shocker.

The experiment was designed to tunnel vision – and it did. But a completely unexpected event occurred. While the vision was being tunneled, the performance of the audible control center decreased. That was not a typo. Tunneled vision led to diminished hearing. Turns out, focusing on something intently led the audio cortex to turn down the volume.

When the researchers performed an experiment to tunnel the hearing, the performance of the visual control center decreased. Again, no typo. Tunneled hearing led to diminished vision.

This led the researchers to conclude that a person intently listening to audible cues, like a radio or cell phone, could have diminished visual performance. It also led the researchers to conclude a person intently focused on something visual could have diminished hearing.

Auditory exclusion

In some cases, when the stress is severe enough, the hearing receptors in the brain may shut off completely. Neuroscience has a term for that. It’s called auditory exclusion. Police officers often report that under stress of a gun fight they are unable to recall how many shots were fired because they did not hear them.

One of my teaching associates, is a firefighter, EMT and former police officer. He shares a story during my classes that drives this point home. One night, while sitting in his police car, he was ambushed by a deranged man with a shotgun. He man shot his police car multiple times, though he, himself, only remembers hearing one shot. The forensics evidence revealed the assailant had shot his car six times. My associate suffered from auditory exclusion, not to mention a whole host of other stress reactions he describes in vivid detail.

Dr. Gasaway’s Advice

The first step in dealing with narrowing attention is to be aware that you are vulnerable to it happening as your stress level rises. Controlling your stress is one of the best ways to impact all of the ill-effects of the hormonal chemical dump that changes your psychological, cognitive, and physical performance. Breathing techniques are very effective for calming that little pea-sized organ in the brain that is the epicenter of your stress response. Control the pea and control the stress.

Scanning your environment may also help combat the effects of tunneled senses. Scanning visually and scanning audibly. If you find yourself becoming fixed on one task or one sound, make a conscious effort to unlock your senses from it and force yourself to scan your environment, perhaps asking yourself quizzically: What am I missing?

Discussion Questions

1. Is it possible that auditory exclusion could cause critical radio traffic, like a mayday, to be missed?

2. Discuss a time when you missed seeing or hearing something because of tunneled senses.

3. Were you ever taught about auditory exclusion during your emergency training?

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If you are interested in taking your understanding of situational awareness and high-risk decision making to a higher level, check out the Situational Awareness Matters Online Academy.
CLICK HERE for details, enrollment options and pricing.

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