LONDON, UK, October 21, 2011 (by Sally Adee): In the basement of a building in South London people shell out GBP 45 (US$72) to spend an hour in a sensory deprivation tank. The shiny white pod is about the size of a SmartCar. Inside, the total-immersion bathtub is flooded with an unearthly blue light and a quietly swishing mass of water that’s been doped with enough magnesium salts to let me float handily on top. I am there to experience sensory deprivation.
In the mid-1950s, John C. Lilly, a psychoanalyst at the National Institute of Mental Health, wanted to investigate what happens to the brain when you experience nothing. Does it run only as a consequence of the constant flood of sensory stimuli the body is subjected to? He wanted to find out whether, in the absence of all sensory input, the brain simply goes to sleep. So he rigged up a soundproof tank in which it’s pitch dark, and in which both the water and air are heated to body-temperature. The salt water removes the sensation of gravity and the temperature is meant to erase the perceived boundary between you and not-you.
So what happens when you experience nothing? It quickly became apparent that the brain doesn’t go to sleep. Quite the opposite. In forced, extended sensory deprivation, some freak out. Some people report that they enter a state akin to lucid dreaming. Others find that they are just incredibly relaxed. Intriguingly, some people claim that floating in a sensory deprivation tank puts them into a meditative state. In fact, they say it’s a shortcut.
Take away every single sensory irritant and distraction, and it makes perfect sense that your brain would slip right into the meditative state. So sensory deprivation is like meditation for cheaters! Right? But actually, the truth is surprising and counterintuitive: for the inexperienced meditator, sensory deprivation can actually be an impediment to achieving a true meditative state. Freed of external distractions, the mind’s every thought becomes evident, and it goes into full gear.
So how is it different from meditation? Funny enough, one of the biggest problems that confounds research on floatation versus meditation is that it’s really tough to find a pure sample. To properly compare “floaters” with meditators, ideally you’d want a group of floaters who haven’t done any meditation. And there’s the rub: As you might expect, people who are motivated to lie in a pitch dark pod for an hour have already had some prior experience with meditation or yoga.