Sometimes during a dangerous or life-threatening situation, it simply becomes impossible for you to attend to all the stimuli coming at you simultaneously. A temporary blindness or deafness effect can take place as a result.

A variety of factors that include high levels of adrenaline in the body from stress or anger can cause inattentional blindness — a temporary loss of peripheral vision, also referred to as temporary tunnel vision. Inattentional blindness is a psychological lack of visual perception that is not associated with any vision defects or deficits. Inattentional deafness is a similar phenomenon that affects hearing and is not associated with any hearing defects or deficits.

In this article, I focus on these sensory distortions — tunnel vision and tunnel hearing — and how to overcome their effects.

How does it happen?

Everyone's reaction to a life-threatening situation will be somewhat unpredictable. Although many accounts of traumatic incidents have similarities, no two are the same.

People working in the military, police, fire or medical fields have experienced numerous sensory distortions including tunnel vision while under stress. If you are not aware that you could experience the world in such a bizarre way, it could add to your stress.

"I told the SWAT team that the suspect was firing at me from down a long dark hallway about 40 feet long," an officer reported. "When I went back to the scene the next day, I was shocked to discover that he had actually been only about 5 feet in front of me in an open room. There was no dark hallway."

Tunnel vision can result from the combination of a fear-induced adrenaline dump associated with a specific, dangerous threat. Because the kind of danger you have to be in to experience a fear-induced adrenaline rush isn't something we can practice in a safe training environment, it is important to study the symptoms so we can recognize them when they occur.

Researchers at Johns Hopkins University ran a series of tests on human subjects with a goal of measuring the loss of visual acuity while engaging them in activities designed to narrow attention. The experiment was designed to cause tunnel vision — and it did. However, while the subjects experienced tunneled vision, they also experienced decreased auditory attention (tunnel hearing).

Researchers discovered that visually focusing on something intently led the audio cortex to turn down the volume as well. According to Drs. Yantis and Shomstein:

"Our findings support several conclusions. First attention affects early visual and auditory sensory responses. The 'push-pull' effect of switching attention between vision and hearing suggests that focusing attention on auditory input (e.g., a cellular telephone conversation) can impair the ability to detect important visual events (e.g., traffic changes while driving an automobile). When attention is directed to the visual system, the strength of audial attention is compromised (and vice versa) leading to potentially significant behavioral impairments."

In other words, a person intently focused on something visual could have diminished hearing, as illustrated in this study. Conversely, a person intently listening to audible cues such as a radio or cellphone could have diminished visual performance.

Real-life example

In this incident, three armed individuals invade a home. As they are searching through the house, they awaken a woman who steps into a doorway. One of the home invaders notices the woman (white hat and jacket), points his pistol at her and begins moving toward her. She opens fire with her pistol.

Look at the sequence of pictures below.

Invaders 1 and 2 immediately begin scrambling to escape through the door they kicked in to gain entry. The woman advances toward the escaping home invaders and fires another shot. As she does this, Invader 3 comes running out of a hallway to the woman's left with his pistol pointed toward her (see Movement 1).

As he careens past, at one point his pistol is pointed toward her head while her pistol is simultaneously pointed at him (Movement 2). Their arms collide as Invader 3 continues running — deflecting both pistols — and neither fires (see white circle in Movement 3).

Invader 3 continues running toward the back door (Movement 4), while she continues advancing and shooting at Invaders 1 and 2, who are firing back at her without even glancing at Invader 3 (Movement 5).

Based on their reactions, I think the woman and Invader 3 were both experiencing tunnel vision. I doubt they even noticed each other at all. She was focusing on the two invaders to her front who were also shooting at her, and Invader 3 was fixated on escaping (he ran through the glass door at the rear of the kitchen).

The full video analysis is available here:

What can we do?

These psychological and physiological reactions to dangerous events have worked well to ensure the survival of our species.

Maintaining an intense and narrow visual focus on a cave lion spotted in the brush may have been a good survival mechanism for the early modern human. Individuals with these traits survived encounters with wild animals, and their families benefited from the increased safety in the immediate environment. This increased their chance of passing their genes onto modern humans.

So, are we stuck with a genetic predisposition that prevents us from dealing with dangerous modern emergencies? No, because we can learn, remember, adapt and practice a plan to deal with emergencies. Training and practice pay benefits.

Going through any simple series of motions causes the neurons in your brain that control that movement to fire in a particular sequence. The more often you repeat a physical sequence, the more "automatic" the sequence becomes.

Just thinking about making those movements stimulates both the neurons in the brain that control those movements as well as the neural pathways in the muscles that command the muscles to move. Research has shown that visualizing emergency procedures can help you actually perform them.

The first step in dealing with narrowing attention is understanding that it can happen as your stress level rises and your body does an adrenaline dump in response. Being able to control your stress is one of the best ways to combat the ill effects of the hormonal chemical dump that changes your psychological, cognitive and physical performance. Breathing techniques are effective if you have time.

If you find you are fixating on one sound or one task, make a conscious effort to unlock your senses from it and force yourself to scan your environment. It may also help combat the effects of tunneled senses if you ask yourself: "What am I missing?"

Practicing reactions to emergencies increases our confidence, and increased confidence lowers the stress response of our bodies when we actually face dangerous situations. Our field of vision is not as narrow as it might be otherwise, and our tendency to fixate on a "fear object" diminishes. Because our brain is in a more relaxed state, it is more able to dedicate resources to creatively addressing new challenges (for example, incoming gunfire from an unexpected direction).

If we practice the right thing instead of simply allowing our natural reactions to rule the situation, we are better able to successfully manage our behavior and overcome the challenges we face in an emergency.