Sensory Deprivation

Sensory deprivation (aka perceptual isolation) is the purposeful stifling of sensory stimuli (either partially or in full), usually of multiple senses. Sensory deprivation is usually achieved with simple methods – blindfolds, hoods, earmuffs, and dark rooms – but can also employ devices for preventing smell, touch, taste, heat or cold, and even gravity. Another device used to enhance sensory deprivation is flotation tanks (body temperature watertanks filled with salt water (high epsom salt- magnesium sulphate). Flotation tanks were invented by the John Lilly, who conducted groundbreaking psychological studies in Sensory Deprivation during the early 1950s. Lilly has been described as an American physician, neuroscientist, psychoanalyst, philosopher and “psychonaut.” His research on the nature of consciousness using isolation takes were the inspiration for the films Altered States and Day of the Dolphin.

Sensory deprivation has been used for a variety of purposes starting with psychological experiments, but also as alternative medical therapy and torture.

Classic effects of sensory deprivation


Sensory deprivation flotation tank

In a classic psychological sensory deprivation study 19 healthy volunteers were placed, for 15 minutes, in a sensory-deprivation room that was devoid of light and sound. Subjects reported seeing visual hallucinations, feeling paranoia (sensing an evil presence) and even depressed mood – at times at the same level of symptoms of psychosis.

When the brain is deprived of normal sensory information it experiences in our environment, it often tries to superimpose its own patterns – this is called “faulty source monitoring,” the brain misidentifies the source of what it is experiencing and tries to construct perception (which may manifest as hallucinations). From my reading psychologist are unsure why some minds unravel so spectacularly when deprived of sensory input.

Time dilation
One interesting effect of a specific type of sensory deprivation (long periods living underground without daylight and clocks) causes ‘time-shifting.’ Although the reasons are indeterminate, research has shown that in darkness most people adjust to a 48-hour cycle: 36 hours of activity followed by 12 hours of sleep. NASA is very interested in the effects of sensory deprivation and time dilation. A couple of experiments demonstrate the results:

“In 1961, French geologist Michel Siffre led a two-week expedition to study an underground glacier beneath the French Alps and ended up staying two months, fascinated by how the darkness affected human biology. He decided to abandon his watch and “live like an animal”. While conducting tests with his team on the surface, they discovered it took him five minutes to count to what he thought was 120 seconds.”

“A similar pattern of ‘slowing time’ was reported by Maurizio Montalbini, a sociologist and caving enthusiast. In 1993, Montalbini spent 366 days in an underground cavern near Pesaro in Italy that had been designed with Nasa to simulate space missions, breaking his own world record for time spent underground. When he emerged, he was convinced only 219 days had passed. His sleep-wake cycles had almost doubled in length.”

Sensory deprivation as torture
Extreme isolation and sensory deprivation can have severe toll on emotional and mental health – sometimes permanent. Prisoners in solitary become withdrawn in a short period of time, and demonstrate hypersensitive to sights and sounds, paranoid, and more prone to violence and hallucinations. Prisoners often show paranoid psychosis after prolonged solitary confinement that is profound enough to require medical treatment. The effects and impact of such deprivation are well known and have been used as a form of torture, but psychologist consider the practice cruel and counterproductive. Children are especially vulnerable to sensory deprivation, which can and does impact developmental advancement.

Therapy – Alternative medicine
Considering the devastating impact of long term sensory deprivation, it is surprising that short term sessions are now being used as alternative medicine therapy (primary as stress management, muscle tension, chronic pain, hypertension, and rheumatoid arthritis) in the form of flotation. There’s no scientific proof that such treatments work, but anecdotal evidence suggest that many people find the experience very restful.

Web applications
None likely.

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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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