Why meditators love caves

Cessations of consciousness and human hibernation

Our new paper is about the most scientifically bewildering state in meditation. If we figure this one out, it’s a goldmine for consciousness research. Possibly revealing about human hibernation, or useful for space travel. Who knows.

My interest in the possibility that one can subdue their own conscious experience began in my early 20s when I read Aldous Huxley’s ‘The Island’. A deeply insightful utopic encore to his ‘Brave New World’. Huxley blends the best of modern technology with archaic wisdom depicted in a society living on a secluded island. There, in his personal paradise, he describes a medical procedure in place for people requiring invasive surgery.

The imagined locals of the island use a process of hypnosis in place of sedative drugs in order to release their grasp on conscious experience and allow them to be cut open without suffering (i.e., “hypnoanesthesia”). This unusual prospect opened my mind to the possibility that, given the right conditions, one could intentionally undo the habit of experiencing. Like general anaesthesia, but voluntary.

Ten years later, I was meditating intensely for a few months and I underwent something very odd. A gap in my conscious experience occurred. Nothing happened but something reset in my brain… no, at the centre of my consciousness. Everything was brand new. Quite literally all my problems disappeared (for a while). My subjective reality was never the same. It was like waking from the longest sleep of your life after just milliseconds of absence.

Another three years later I met a friend of a friend and he told me about a meditator who can “turn off his consciousness”. He showed me a recording of a Muse headband where there was no apparent signal during the period of “cessation”:

I was very, very sceptical. No brain activity? No way. I figured it was a malfunction with the device or it just wasn’t sensitive enough to make sense of unusual brain dynamics. It’s a market device, not a scientific one.

Still, it was interesting. We decided we should at least have a conversation with the guy. We set up a Zoom call. He was based in Asia at the time. Three of us scientists (two full professors) spoke with him for over an hour. I may share the recording one day.

It was mind-blowing. His description was just… simple, clear, and grounded. No nonsense. The guy was very convincing. Could he really just “turn off consciousness” It was striking that his description resonated so well with our own scientific understanding of how experience is constructed. It seemed like what you would expect if you gradually deconstructed and then reconstructed the mind.

But it got even wilder. He claimed to be able to go lights-out for up to six days at a time (not risking longer in case of, you know, death). No bathroom. No food. No water. Total absence. He told us about an experience where he was meditating in a cave just before the COVID lockdowns started.

He explained how he was practising long “cessations” there. But then one day he woke up back in his friend’s bedroom. It turned out the government had called a lockdown, so his friend had come to get him. Everyone needed to be inside their houses, ASAP.

The problem was that when they found him, they couldn’t wake him up, no matter what they tried. They thought he might be dead or comatose (upon closer inspection), but when they reached out to his meditation teacher, the teacher reassured them that he was fine. He told them to just keep him safe and warm and he’ll wake up on his own accord. He did eventually wake up, but much to his own confusion his cave had turned into a bedroom! His first thought was that he had died and moved on to the next realm.

Now to be clear we were highly sceptical and in some ways still are. But it just wouldn’t have been honest of us as scientists not to explore this possibility a bit further. Despite the risk of lost time and resources. I mean, what did he have to gain from lying about this? He seemed totally open to being rigorously tested. No qualms at all. I’ve seen some wild stuff on my own meditation journeys, but the other two scientists had nothing to compare this to. And yet, even they were open-minded after the conversation

So I started reading everything I can about this strange meditation-induced absence of consciousness. I discover that in classical Buddhism this event is called “Nirodha”, or specifically in this case, “Nirodha Samapatti”. I discover that there are detailed descriptions of how to enter the state, what to do before entering it, and how long to stay in order not to die. I also learned that it was distinguished from death 2300 years ago in the Maha Vedalla sutta (Nanamoli & Bodhi, 1995), as follows:

“In the case of the one who is dead, who has completed his time, his bodily, verbal and mental fabrications have ceased and subsided, his vitality is exhausted, his heat subsided, and his faculties are scattered. But in the case of a monk who has attained the cessation of perception and feeling, his bodily, verbal and mental fabrications have ceased and subsided, his vitality is not exhausted, his heat has not subsided, and his faculties are exceptionally clear.”

I discover that it’s pretty much the most advanced demonstration of contemplative talent—resembling a kind of emergent skill of enlightenment: “I have such control over experience that I can disappear myself!”. Beyond giving the practitioner immeasurable bragging rights, it also results in a powerful reset to the mind and can help the practitioner gain further insight into how the mind creates itself through ‘links of dependent origination’.

Obviously, there’s a lot more to it. Like enlightenment, for example. But let’s jump over that little fire for now.

So at this point, I’m really curious. And I’m having a chinwag about it with my housemate at the time (Igor Djakovic). He’s definitely a sceptic, but overheard our Zoom conversation and also became curious. He’s an archeologist, and the first thing he said was “…man, that sounds like hibernation”. And I’m like “nah, come on”. That can’t be right. But then again… they do go into caves to do this. And they do seem particularly good at it in the Himalayas where the winters are cold. Hmmm.

When another one of our co-authors (Prof. Henk Barendregt) independently brought up the idea, we started to give it some more thought. It wasn’t long ago that our common ancestors could do this, so maybe that’s where the capacity comes from? I don’t know. I’ll post more details about this hypothesis in a few weeks.

Fast forward about 12 months and this mysterious meditator is at our lab in Amsterdam. He’s quiet, relaxed, and strikes me as completely ordinary. No particularly intense energy or presence, just calm and receptive. Despite the fact that we have a documentary crew and half a dozen scientists plus interns poking at him. After lunch, we plug him into the EEG (electroencephalography) among lots of other gadgets. We measured heart rate, blood oxygen saturation, movement (including eyes), respiration, temperature, nervous system activity, and more.

We collect a bunch of data under different conditions (including nirodha samāpatti). We do it again on the following Monday including a condition with a short nap. Is it different from sleep, we wondered?

We’re still analyzing these data. Some of the results are unremarkable. The brain definitely did not turn off (that was a relief), and neither did the heart or breathing stop. In hindsight this makes sense. Changing the body’s homeostatic balance too suddenly would be dangerous. Even hibernating animals can take days or weeks to experience changes to their physiology. But our other data is intriguing.

The preliminary data that we share in this (mostly conceptual) article, I can mention. The rest will be released later this year. I can tell you at this point that there are also other interesting results but you’ll have to be patient. So, here’s what I can tell you.

Unbeknownst to us, our colleagues in the psychiatry department of Harvard led by Dr. Matthew Sacchet were, almost around the same time, testing their own advanced meditator on a similar but slightly different capacity known as ‘fruition’.

Fruition is also often accompanied by a short cessation. They observed that alpha synchronization decreases gradually before the cessation event, dramatically peaks at cessation, and then returns to normal levels a short time after. So naturally, we thought it would be valuable to replicate their findings.

Just like them, we found a robust reduction in neural synchronization in the alpha band. The alpha band is a frequency of neural activity usually in the 10-12 hz range. It is the most dominant and resonant frequency in the brain. Specifically, the breakdown in coherence or synchrony was highest in cessation, followed by the nap, and then the control condition. So, cessation desynchronizes neural activity in the brain, but why, and what does this mean?

In our paper, we propose that meditation begins by flattening the hierarchy of abstract processing (see our other unifying theory of meditation). Then, the cessation follows from an active (meditation-induced) dis-integration of experience and hence a desynchronization of neural activity.

Desynchronizing neural activity results in a breakdown in information integration: the key mechanism that binds our experience together into a unified whole gets a mortal blow. Similar desynchronization results are found when you take enough propofol or ketamine.

Remember that all our sensory experiences reach the brain at different times and are processed in different areas of the brain. If these events are not successfully integrated it is not possible to have a coherent conscious experience. To disintegrate them is to disunify consciousness.

We suggest that this ‘unbinding’ begins at high (abstract, deep) levels such as thinking, and gradually deconstructs earlier and earlier levels of being, such as experiencing. This interpretation seems consistent with the reports of meditators, who comment on the fundamental need to deconstruct what are called ‘the five aggregates’ in Buddhism.

These aggregates, as I understand them, simply describe the various qualities that need to come together in order to create a conscious, coherent, sense of being. Through meditation, one separates them, as well as recognises the three characteristics (impermanence, non-self, and suffering).

Thus, when the unbinding begins to touch our most axiomatic assumptions about what constitutes consciousness, it may all suddenly just come apart: the mind unbinds. And if the deconstruction (via desynchronization) is deep enough then even consciousness may no longer appear.

For now, that’s just a hypothesis. We’re also discovering new things about this unusual state every day and we have a lot of data to analyze yet. If you’re curious about the details you can check out the paper (full pdf here), where you can also read more about the hibernation idea.

This wouldn’t have been possible without all the co-authors and many others involved. Thank you to the Suttavada Foundation for their support, the ERC, and other donors. Stay tuned for the much bigger data-driven paper later in the year.