If you're unlucky enough to be an Iranian dissident, you probably know about white torture. Also known as sensory deprivation, it's a nasty piece of work.

You do not have to cause pain to break someone. All you need are blacked out goggles, noise ringing headphones and time. Lots of time.

The brain is excellent at extrapolating meaning from snippets of data. A few dimples on bright red flesh makes you think “strawberry”. Two dots and a curve look like a happy face. A brief odor conjures memories, emotions and actions.

But when there's no data to find meaning in …

Well, that part of you is still active. It still looks for the meaning in data that is not there.

Your brain craves novelty, interaction and stimulus. Strip that away and it's like turning the brain against itself.

You do not get used to it. Time only makes it worse.

I would not wish it in my worst enemy, assuming I had one.

I would recommend it as a meditation technique though.

In small doses, sensory deprivation is a valuable tool for probing your psyche. It's calming to be away from all that noise and distraction. What makes it pleasant, as opposed to torture, is that you can walk away from it. Stimulation and deprivation in a continuous cycle.

You can experience this by renting a flotation tank for an hour or so. You float in a saline solution, with no sound and nothing to see. It's incredibly centering.

If you want to try it on your own, all you need is an eye mask, headphones and some white noise. YouTube has plenty of tracks.

Set aside some time, close off the world and go inside.

What this does is interesting. I mentioned your brain's instinct is to extract meaning from small signals. I also mentioned that this keeps happening, even during sensory deprivation.

The experience is just like dreaming. Random images flash before your eyes. Your brain does the best it can with what few signals arrive. Is that a squirrel or a fireplace? What color is that … bicycle?

But as soon as it has an image, it discards it and tries something else.

I was surprised by how quick and intense these hallucinations were. I think it only took a few minutes before it immersed me completely. Then again, it's hard to measure time in this state.

This may be one of the easiest meditation techniques, but I do not recommend it for beginners. After all, you're playing with fire here. It's safe enough for most people – having said that, knowing how to control your experience helps.

I see why people use white noise to fall asleep though. Once I started dreaming, it was hard to stay awake.