Hypnogogia and hypnopompia are hallucinations that occur as you’re falling asleep or waking up, respectively, and are accompanied by sleep paralysis. In other words, they’re hallucinations that occur between sleep and wakefulness (or vice versa) and, while you’re hallucinating, you can’t move because you’re paralyzed. While sleep paralysis is entirely desirable while you’re asleep (acting out dreams isn’t good for one’s health I’m guessing), it is possible to be semi-awake and mostly aware of your surroundings while still paralyzed. Surprisingly, sleep paralysis is quite common (about 25-40% of people report experiencing it) and, although incidence seems to vary across cultures, it’s found worldwide (Cheyne, Rueffer, & Newby-Clark, 1999). Importantly, sleep paralysis is not always accompanied by hallucinations, about 30% of respondents in one survey said they had experienced sleep paralysis without hallucinations. Indeed, I’ve experienced sleep paralysis (sans hallucinations) probably half a dozen times or so and was never bothered by them much. (On one occasion I got rather frustrated though – I was awake and kept trying and trying to move but couldn’t. In retrospect, I’m a bit perplexed why it didn’t bother me more).
Around 3 a.m. on November 23rd, I woke up and heard my sister Liana’s voice. At first I thought I was back in Chester House in Cape Town (where I lived with Liana for ~ 2 years, in a bachelor’s flat) but then the voice started angrily lecturing me and telling me details of the dream I just had. (Probably due to sleep inertia, I don't now remember what I dreamt, but I distinctly recall the voice referring to minute details of my dream). This went on for about 5 minutes and as I slowly became aware of where I was - about 1,500km away from where Liana lives - I realized the voice was disembodied and became more and more frightened. I must emphasize, in fact, that the word “frightening” doesn’t come near to doing justice to the feeling. It was numbingly scary, petrifying, bloodcurdlingly terrifying.
And this, remember, was my sister’s voice — not something I’m scared of under normal conditions. Other people who have these hallucinations report not only hearing things, but experience visual, tactile and proprioceptive hallucinations. They report seeing old hags, demons, aliens, ghosts or other malevolent beings or report experiencing floating or falling sensations and so on. The fact that I just heard my sister's voice makes me suspect I had a fairly mild hallucination; I can only imagine how much more frightening it must be to see, say, an alien next to your bed while you're supine and paralyzed.
That brings me to my subtitle: "How I Learnt to Stop Belittling True Believers and Love Skepticism". For me, having this experience has really driven home the argument, made most forcefully by Carl Sagan and Joe Nickell, that it's a false dichotomy to think people who have paranormal experiences are either lying or crazy. There's a third alternative: they're having genuine experiences but then interpret the experiences incorrectly. That is, people really do experience what looks for all the world like an alien standing over their bed — but it's not really an alien, it's a phantom in the brain. And that's why I've learnt to love skepticism (even more): as soon as I woke up and got over my sleep inertia, I realized what had happened and was no longer afraid. My sister was due to give birth, so she was in my thoughts; I knew what sleep paralysis was, having experienced it before, and I knew about hypnopompic and hypnogogic hallucinations from The Skeptics Guide to the Universe podcast. (Thanks guys). So as soon as I thought about it clearly, I knew what had happened, could place my experience in perspective and I was thus saved from further negative emotions and a silly ontology.
My experience also made me realize just how compelling seemingly paranormal experiences can be. It's completely understandable that someone who regularly has hypnogogic hallucinations, lacks training in skeptical or critical thinking, knows nothing about neuroscience, and who is immersed in a popular culture full of references to paranormal entities will interpret such experiences as genuinely paranormal events. Belittling the experiences of the true believers in the paranormal, I now believe, is not appropriate — they deserve our sympathy, not our ridicule.
- Sleep paralysis accounts.
- Skepdic on sleep paralysis.
- Chris Mooney, "Waking up to sleep paralysis", Doubt & About blog.
- Joe Nickell, "A Study of Fantasy Proneness in the Thirteen Cases of Alleged Encounters in John Mack's Abduction", The Skeptical Inquirer.
- Susan Blackmore, "Abduction by Aliens or Sleep Paralysis?", The Skeptical Inquirer.
- Robert Novella, "Hypnogogia: An Explanation for Strange Nighttime Visitations", The Connecticut Skeptic.
Cheyne, J. A., Rueffer, S. D., and Newby-Clark, I. R. (1999) “Hypnagogic and Hypnopompic Hallucinations during Sleep Paralysis: Neurological and Cultural Construction of the Night-Mare,” Consciousness and Cognition, 8: 319–337