Sensory Overload

Our senses are constantly bombarded by sight, sound, touch, taste, smell and balance, and more. Our brain takes information in,and processes it to create a picture of reality, and without our knowing edits out information that it doesn’t consider essential. When under stress a brain can experience sensory overload (not to be confused with information overload). There’s a subtle difference between Sensory Overload and Information Overload.

  • Sensory Overload is when too much sensory information overloads the brain’s ability to intake, causing either a sensory blackout (no seeing, hearing something) or a perception distortion.
  • Information Overload involves the number of data points – too many pieces of information and the ability to keep track of them all fails.

controlscreenInformation Overload: an Air Traffic Controller (ATC) is monitoring 20 flights on approach and departing the Dallas Fortworth airport when there’s a computer glitch and another controller has to turn over 10 additional flights to him. The ATC now must monitor 30 flights – speed, altitude, rate of decent, rate of ascent, vector, position, and operational situation.

Cockpit.jpgSensory Overload: A fighter pilot is in the middle of a dog fight and all of the following happens in a few heartbeats. The pilot is maneuvering on the tail of an enemy aircraft, he catches the site of an enemy fighter passing on his left. He is pushing his aircraft to maximum tolerance speed so he is constantly checking his air speed, his left hand pulling back slightly on the throttle. At the same time he knows he’s at relatively low altitude, so he glances at the altimeter. The sun is shining into his cockpit over his right solder and shadows change across the cockpit as he turns with the other plane. He hears the radio as from someone in his squadron calls for help, and his base command calls in for a report. He feels extra Gs as he goes into his turn, and a bead of sweat rolls across his face. His wing-man calls to him, “You’ve got one on your tail,” but he never hears that last message. Pilots have been known to fly their planes straight into the ground under such sensory overload situations.

It’s surprising to think that our brain can block stimuli but there’s a very simple example that most of us have experienced: you’re at a lively party and trying to hear a friend tell a story, but they are sitting down the table from you. If you watch your friend’s mouth movements (visual cue) you can combine that information with their voice, hear what they are saying, and tune out the person talking behind you. But we can only do that to a certain point before our ability to discriminate sensory input fails.

Multitasking & Sensory Overload
There’s been quite a bit of discussion over on the pressures our current society puts on individuals – multitasking and the constant use of smartphones – and whether this constitutes sensory overload. One point we know is that we are not nearly as good at multitasking as we believe. The brain doesn’t really multitask (cognitively) it switches from one task to another. There’s a simple experiment you can try to prove the point. Have someone time you on the following task: draw two horizontal lines on a piece of paper and on the first write “I am a great multitasker” on the second line write out the numbers 1-20 sequentially, 1 2 3 4 5 6 …” that usually takes about 20 seconds. Now, do the task again, but this time interchange writing one letter then a number as,  I, 1, a, 2, m 3 … This multitask takes on a much different degree of difficulty.

Brain plasticity
There’s also a certain plasticity of the brain involved in the brains ability to process sensory data. A perfumer will hone his ability to detect scents (and not be overwhelmed by them), a musician will train her hearing to actually hear sounds that non-musicians cannot, and an astronaut will often have to readjust to the weight of bed sheets after returning from time on the International Space Station. We can adjust to a certain level before overload happens, at least some of us.

Sensory Overload can also result from illness or condition. People with Autism or Schizophrenia are often suspected of experiencing sensory overload, but it can also be a side effect of chronic fatigue syndrome, post traumatic stress disorder, generalized anxiety disorder, or migraines. For those individuals the world can be perceived like this:

Web Applications

Visual sensory overload already happens on Web pages. Busy pages are often too much for readers to consume and the scanning/information hunting skills we’ve already developed ignore information such as ad banners, long headlines, and lengthy paragraphs that our brains consider of low importance. Good graphic design (a professional designer) and standard usability practices must be used to deliver information that helps the reader find the information they need, and not overload and turn them away. Sensory overload will take on special meaning as virtual reality technology advances.

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