How Does Hypnosis Work?

“And as to the people you want to help, they are in their respective worlds for the sake of their desires; there is no way of helping them except through their desires.”—Sri Nisargadatta Maharaj, I Am That

High School Hypnosis

Hypnotists cast a captivating spell. It is a curious sight to see people apparently stripped of autonomy and persuaded to act against their will—so curious, in fact, that few can watch hypnosis without being intrigued by what, exactly, is happening.

Whenever I’ve sought out how hypnosis works, I’ve always been disappointed by the answers on offer. Most sources (hypnotists included) say that it functions by inducing a relaxed, focused, trance-like state which makes the hypnotee open to all manner of suggestion. But this begs the question: how do relaxation, focus, and trance make someone so suggestible in the first place?

Until recently, the best answer I’d heard came the night of my high school graduation.

Every year, the graduating class of Kalamalka Secondary School is treated to a supervised all-nighter of swimming, games, and—most memorably—an hour with a hypnotist. In 2008, my friend Gustav was successfully hypnotized. When the hour ended and he returned to normal, I asked if he understood what had taken place. How was he convinced, in front of over one hundred giggling peers, that he was alternately a table, a racecar driver, or whatever else the hypnotist proposed? I didn’t expect much, since I’d heard that hypnosis is like sleep and cannot be recalled. But, as it turned out, Gustav remembered everything. And, as is often the case with big reveals, his explanation was both illuminating and disappointing.

As he explained, he did what the hypnotist suggested simply because it seemed like a good idea at the time. No trance, no hallucinations, no altered states of consciousness: Gustav was aware of being hypnotized the entire time, and he played along purely because it felt like the right thing to do.

This made sense, but I hoped it wasn’t true. If someone wants to do what’s asked of them, of course they will! Surely, there is more to it than this. I wanted hypnosis to be a raw, real feat, but Gustav was saying that it was basically a camera trick of the mind—less David Blaine, more Criss Angel.[1]

Was it possible that Gustav was a faker who managed to slip past the hypnotist’s discriminating gaze?  Or was he right, and hypnosis is just a willing obedience mustered to please both hypnotist and audience?

Hypnosis at Home

I recently had the pleasure of being successfully hypnotized, and now, over a decade later, I understand Gustav’s explanation in a new light. He was correct: hypnosis does simply lead you to do what feels right. And I was wrong: this is a real feat, well worth wondering about.

Contrary to common belief, hypnosis does not subvert people’s autonomy. It actually frees them, allowing them to speak, act, or even perceive as requested, without pesky inhibitions getting in the way. To coax out this freedom of mind, the hypnotist plays upon many quirks of psychology—only one of which is the desire to please onlookers and authority figures. To help explain the ingenuity with which hypnosis exploits these quirks, let’s reflect on my own time under the influence.

It was a sleepy August night and I was preparing to pack it in when, true to her spontaneous self, my then-girlfriend asked if I wanted to be hypnotized. I agreed, but doubted it would work. For starters, Anni had never hypnotized anyone before; she would just be reading from a script. Then, there was the fact that I’d never managed to be hypnotized, and not for lack of trying. But maybe this time would be different: here was someone I trusted (more than either the high school hypnotist—who had the air of a salesperson—or the various YouTubers I’d tried over the years), in the safest of settings (as someone wary of crowds, I have little hope of ever being hypnotized in public).

These feelings of trust and safety helped me relax. And relaxation is important because, as I’ll explain, hypnosis is the act of guiding people to mental states of least effort. Without relaxation, one’s mind is too vigilant to settle into such states.

Eyes Wide Shut

For this reason, Anni’s instructions began with a call to relax. Once I was settled she had me close my eyes, suggesting that it might become impossible to open them, regardless of my efforts. When I gave it a try, despite a few docile thoughts about lifting my eyelids, they did not oblige. Then, I then did exactly what was expected of me: I stopped trying and just let them rest.

There I was, pleasantly tranquil, when I was offered a choice: I could open my eyes, ruining both my relaxation and the hypnosis, or I could leave them closed. Faced with these options, the choice was made with so little deliberation that it was hardly a choice at all. By putting me in a relaxed state with no reason to interrupt it, Anni all but ensured that her suggestion come true. No matter how hard I tried—which, given the context, was never going to be much—my eyes stayed shut.[2]

Although keeping one’s eyes closed is, in itself, unremarkable, this felt different than merely shutting them to nod off. I knew that I was doing what Anni wanted, but she’d just shown that her instructions and my wellbeing were perfectly in sync. It was exactly as Gustav had said: I wanted to do what she was asking—and neither my awareness of the process, nor my budding understanding of how I was being influenced, got in the way.

Lost for Words

Anni then segued from the physical to the more cognitive parts of my mind. She explained that if I paid attention, I would soon notice that I’d lost the ability to speak. Try as I might, no words would leave my lips. And, as with my eyes, she was right. Like before, this instruction played to my desire to remain relaxed, but it now transcended mere physicality and was probing the language-generating parts of my mind.

And something remarkable happened next.

Anni told me to think of my birthdate, and hold it in mind a brief while. Then, she said, I’d notice the thought slipping away and would be unable to retrieve it. As she explained, any attempt to access my birthdate would be blocked by a soup of random numbers in its stead. And, yet again, she was right. The thought “November 17^th, 1990” was now off limits, and whenever I reached for it I found myself suspended in numerical limbo, floating freely amongst a jumble of numbers.

As spectacular as this seemed, it was the same process that took place previously: hypnosis presents a garden path, filled with apparent choice, but only one route is grooved towards psychological ease. In this case, it took less effort to float amidst a sea of numbers than to dive down for a distinct set.

Inverted Seeing

In the last part of the night’s hypnosis, Anni quite literally turned my world upside down. She told me to open my eyes, stare at the ceiling, and notice something peculiar: instead of lying on my back staring up at the ceiling, I’d be staring down at it, as if it were below me. True to form I found myself, impossibly, looking down at the ceiling from the ground above. This brought on the twisty feeling of being pressed into the roof, backside up, suspended over a barren floor with orange peel texture.

How does this experience fit the explanation of hypnosis presented above? Surely, flipping the world upside down takes more effort than seeing it as it is.

Not necessarily.  

The first thing to understand here is that nothing in my visual field actually changed. Hypnosis is impressive, but it’s not magic. The same photons were striking my same retinas, such that the ceiling still looked like the ceiling—hypnotized or not.

The next thing to understand is that the act of seeing is not one thing. Vision is an ongoing process of interpretation, subject to influence in numerous ways. Optical illusions provide a behind-the-scenes peek at this process. Take, for instance, the familiar illusion in which, after staring at an abstract blur for a few moments, you realize that it’s been hiding a face (or a dalmatian, or whatever).[3] And, once you see the face, you have trouble unseeing it. This illusion (along with countless others) shows that what we see is not a direct consequence of what we’re looking at.

The final thing to understand is that the interpretive, multifaceted nature of vision makes it more pliable than we generally assume. Visual backdoors exist, which are regularly exploited by visual artists, vision researchers, and, indeed, hypnotists. Anni may not have been able to change what I was looking at, but she didn’t have to. She just had to change how I interpreted it.

Maps Hiding in Plain Sight

We tend not to recognize the ways we make sense of the world. This is especially true with vision. We rarely notice how objects near our focal point seem bigger than they really are, or how sights below the horizon line occupy more visual real estate than those above (these are just two reasons that mountains look puny in vacation photos).[4]

Another thing we don’t notice is how we automatically orient our visual scene relative to a cognitive map of our surroundings. Take a moment to reflect, and you’ll notice this map running at all times. Look to the left, and you preserve a sense of what’s on your right; look out a window, and you’re met with an impression of the surrounding geography. Without this cognitive map, sights would consistently disorient us and vision would lose much of its value.

As with much of mental life, this mapping takes place on the sly—until it goes awry. This can happen when we sleep in unfamiliar locations. When staying at my parents’ house, for example, I sometimes wake up, groggily glance about, and am confused by the orientation of the room. Upon remembering that I’m no longer in my Vancouver apartment, however, the correct map snaps into place and I can navigate to Mom’s morning coffee without issue.

Such occurrences show that sights can come unmoored from the maps which give them meaning.[5] And this unmooring is aided by relaxation. As a child I used to play a game in which I would lie down, close my eyes, and imagine that I’d rotated 180˚ relative to my surroundings. This was no easy feat, since my mental map stubbornly refused attempts to consciously reorient it. I could only succeed if, instead of trying to force things, I first relaxed and let the map’s hold loosen. Only then was I able to swap in a new orientation.

With this in mind, it’s not hard to see how Anni inverted my world. By this stage relaxation had subdued my cognitive map, so when she suggested a new one I was free to take it on board. And besides, none of her previous suggestions had led me wrong—so why would I try doing otherwise now?

It’s as simple as that, and in truth it is actually not that extraordinary. As an adult, I sometimes playfully imagine that the ground is really a giant wall, and I’m perpetually walking up it—which is already 90˚ towards flipping the ceiling beneath me.

This is where my night of hypnosis ended. Readers might be disappointed that I was never hypnotized into hopping on one foot, quacking like a duck, or making embarrassing confessions, and may be left wondering what hypnosis makes possible, and where its limits lie. We’ll close with a few thoughts on this.

Getting Sleepy

Pop culture portrays hypnosis as a kind of mind control, where people “get very sleepy” before losing autonomy and acting counter to their will. This is wrong. Hypnosis doesn’t override people’s agency, substituting the hypnotist’s will for that of one’s own. Hypnosis enlists agency, such that the will and wellbeing of the hypnotee perfectly coincide with the intent and instructions of the hypnotist. When these forces align, the process of hypnosis is all but guaranteed.

This is not unique to hypnosis. The same thing happens whenever you encounter the guidance of a great teacher: they present a possible path which you then willingly go down. Far from removing agency, skilled teachers provide it with fulfilling outlets.

That said, the “getting very sleepy” stereotype has some truth to it, in that both hypnosis and sleep involve relaxation. By calming the thinking mind, hypnotists induce a less critical, more receptive state. When unburdened by thought, we’re free to behave in ways which might otherwise be unthinkable. At my high school grad, this led Gustav to sit in front of his classmates and act, amongst other things, like a table and a racecar driver. In a different context, he might have shrugged and asked “why?”.

But because hypnosis subdues thoughts, its influence is limited. Gustav may have acted like a racecar driver, but he never believed that he was one (recall that he knew he was being hypnotized the entire time). Had the hypnotist tried to convince him otherwise, the ensuing cognitive racket would have likely ended the hypnotic state. I suspect that, absent conditions akin to torture, hypnotists have little power to radically alter core beliefs.[6]

In a sense, hypnosis is not so different from simply socializing. Speaking with others causes us to experience thoughts, emotions, and intentions which wouldn’t have arisen otherwise. It also inclines us towards agreeability, to avoid feelings of unease. And if the conversation grows too challenging the resulting discomfort can lead us to grope for reasons to exit the conversation, foreclosing further socializing.

Hypnosis is a one-way anxiety-free conversation, consisting entirely of agreeable suggestions. In this context, the thought of resisting—itself a form of anxiety—never comes to mind. In How to Win Friends and Influence People, Dale Carnegie wrote “The only way I can get you to do anything is by giving you what you want”. He was referring to socializing, but he could just as easily have been talking about hypnosis.

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[1]Granted, I’ve gained much respect for Criss Angel after watching scenes like this.

[2]I was pleasantly surprised to have passed this first hurdle. Back in high school, I followed the hypnotist’s words—from the safe anonymity of the audience—but struggled to keep my eyes shut, my amygdala insisting that I keep sneaking peeks.

[3]The Ukrainian artist Oleg Shupliak has fun riffs on this illusion.

[4]To see how vision expands the ground relative to the sky, try the following: next time you have a view out to the horizon, look through your legs (upside down) and notice how the sky grows and the ground shrinks. This same trick also works to nullify the moon illusion (when the moon appears preternaturally large just above the horizon), shrinking it to “normal” size.

[5]This is not just true of sight. No experience contains intrinsic meaning—and learning to see this can be profoundly liberating, because it frees you from the torrent of imperatives implied by ascribing meaning to moment-to-moment existence.

[6]Some people claim that hypnosis helps with smoking cessation or weight loss. If true (which is apparently a big if), I doubt anything strange is happening. Similar to meditation, hypnosis opens your mind to the fact that letting desires arise and pass is more relaxing than chasing after them. To cease compulsively pursuing desires is to cease a great deal of suffering, whether you’re trying to quit smoking or not.