What is a sensory deprivation tank and what does this experience feel? And most importantly, should you try it?
John Lennon was not referring to actual floating when he sang, “turn off your mind, relax, and float downstream” in the Beatles’ groundbreaking 1966 record “Tomorrow Never Knows.”
Rather, the song was inspired by The Psychedelic Experience, Timothy Leary’s how-to guide for LSD users, based on the Tibetan Book of the Dead. But (presumably unbeknownst to Lennon at that time), there is a way to have your own psychedelic experience, without drugs, via flotation!
What is a sensory deprivation tank?
The sensory deprivation tank (also known as an isolation tank, or the more therapeutically marketable but less descriptive “flotation tank”) was invented by Dr. John C. Lilly in the 1950s.
The question he wanted to put to the test was this: if you neutralized all input reaching the brain via the 5 senses, what would it do? Simply shut down? Or create its own stimuli?
The second answer proved to be correct. Lilly was astonished at the elaborate hallucinations he experienced when spending extended periods of time in the tank. Then again, he spent hours and hours there, often under the influence of LSD or ketamine (both unregulated at the time he used them).
Since those heady days of consciousness-exploration, the tank experience has been rebranded as a therapeutic spa experience, often given the acronym REST, for Restricted Environmental Stimulation Therapy.
My experience with a sensory deprivation tank
I’ve tried it a few times myself, in both Norwich, England, and Houston, Texas. Chances are there’s a provider near you; try Google. They range from major spas to home businesses run by charming eccentrics.
The way it works is this: you climb into a lightproof, soundproof vessel (perhaps with earplugs and a mask) and shut the hatch as you recline in a shallow pool of water, heated to a lukewarm temperature and saturated with Epsom salts.
These are to increase buoyancy, so you rest in zero-gravity, on almost an invisible mattress of water, as one famously does in the ultra-salty Dead Sea. The magnesium in them is said to be good for your skin, but it can be irritating if you have any cuts or abrasions.
Personally, I was distracted in one of my sessions by an itchy eye, which I rubbed with my saline-covered hand, exacerbating the problem and definitely taking me out of my alpha-wave state.
But in my other, more successful sessions, I found the flotation tank to be a marvelous and fascinating tool for achieving altered states of consciousness. Upon first getting into the tank, there’s an initial period where your mind is still functioning in its usual busy daily way, and you’re consciously thinking about what you’re doing, how strange it is, feels nice, etc.
Then as you settle into the experience, there comes (or did for me) a brief interlude of anxiety or claustrophobia, which I think is that phenomenon described above: the brain realizing that it’s deprived of its usual stimuli, then racing to fill the void. This resolves itself and is followed by a state of extraordinary peace and relaxation.
Just about then, your hour is up, which can be a letdown. I recommend booking for two hours. This allows you to abide awhile in that alpha state, and by the end of your session, you get a glimpse of the truly trippy potential of this device.
Your sense of spatiality and the boundaries of your own physical body are blurred, and your brain is likely to go to some weird places, almost like a waking dream.
Lilly himself got really far out, writing in his books of fantastical experiences involving inter-dimensional travel and contact with alien entities.
That won’t happen to you in a sensory deprivation tank session (perhaps, unfortunately, depending on how you look at it), but you will emerge from your bizarre baptism with a feeling of mental and physical rejuvenation.
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