rachelmanija (![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
rachelmanija) wrote2013-02-01 03:34 pm
rachelmanija) wrote2013-02-01 03:34 pm
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Hallucinations, by Oliver Sacks
A book on hallucinations which are not caused by schizophrenia and other psychotic disorders. (It also doesn’t deal much with culturally normal hallucinations, which is too bad.) Hallucinations – sensory perceptions which occur during waking and are not based on consensus reality - are surprisingly common, and include many experiences which probably most people don’t think to define as hallucinatory.
While drifting off to sleep, with my eyes closed, I often see kaleidoscope-like geometric patterns, faces (often grotesque or witch-like), and occasionally swarming insects. They are not dreams, are not perceived as being part of reality or projected into the real visual field, and do not have emotional connotations. I always assumed they were caused by going from visual perception to blank darkness while drifting toward sleep: a sort of meditative optical illusion/visual imagination.
They are called hypnogogic hallucinations and are extremely common, and the particular things I see are commonly seen, along with other stereotyped visuals. (“Stereotyped” as in common to people who experience the phenomenon, as opposed to “unique.”) They are caused, in simple terms, by the visual centers of the brain “idling” before sleep.
Hypnopompic hallucinations are less common, and are more vivid, often briefly perceived as real, often frightening illusions which occur upon waking from sleep. I've had those too, thankfully only a few times; mine were quite unpleasant, full-sensory illusions of being entombed in stone. They were not nightmares, though; I could also see my real surroundings. Once someone in the room with me verified that I had my eyes wide open and could track movement and respond to voices.
I have also sometimes, while wide awake, heard my name being called, when no one is there or when nobody called it. This is also extremely common. People in dangerous situations often hear voices giving helpful commands or suggestions; grieving people often see or hear their loved ones. These phenomena are common and “normal.”
I wish Sacks had analyzed those situations more in neurological terms, because I find that fascinating. The main theory he suggests, regarding auditory hallucinations in general, is that they’re a glitch caused by the brain failing to recognize its own thoughts. Another possibility is that people become consciously aware of the non-verbal stream of consciousness beneath their articulated thoughts, and perceive it as coming from the outside.
Sacks covers a number of hallucinatory experiences caused by neurological conditions, such as Charles Bonnet Syndrome, in which blind people hallucinate certain types of sights. Also, in a fairly funny chapter, his own youthful drug use.
The non-psychotic hallucinations are typically either never experienced as “real,” or are easily believed to be unreal once someone explains that they aren’t real, or are understood to not be real once they’re over. This is quite different from psychotic disorder-type hallucinations, which are often believed to be real, even when they end. (A person with PTSD may hallucinate, but they typically either always know the hallucination isn’t real, or, as in the case with flashbacks, figure it out in retrospect.) Regarding culturally normal hallucinations like ghosts, people may believe that they did literally see a spirit, but they also regard it as a spirit – a visitor from another realm. That’s a different experience from literally believing that Abraham Lincoln is living in your guest bedroom. (To avoid wank, let’s assume that I am only discussing those perceptions of spirits, God, etc, when they really are hallucinated and not objectively real.)
Hallucinations without accompanying delusions don’t usually cause major life problems for people. They are not “crazy,” though they might worry that they are. Delusions seem to be what cause the life problems.
The book is well-written and intriguing, as one would expect from Sacks, but more descriptive than analytical. Some types of hallucinations, particularly visual ones with a clear-cut neurological basis such as migraine auras, are explained in neurological terms, but others are simply described. The descriptions are quite evocative and the material is fascinating, but I would have liked more neurological speculation, especially on why certain situations or conditions create certain types of hallucinations, like fever deliriums causing distorted perceptions of size, which are almost invariably perceived as unpleasant or threatening.
I also wish he’d covered auditory hallucinations in more depth. At times he speculated on historical figures who might have heard voices. The problem is, many people write about the simple perception of their own thoughts in voice-like terms, so it’s very hard to tell whether someone literally meant they heard a voice, or only that their thoughts were so vivid that they seemed voice-like. It seems entirely possible, too, that two different people might have a neurologically identical experience, but one might attribute it to an outside voice and one to distinctive inner thoughts.
Please discuss your own experiences of and theories on hallucinations, if you wish.
Hallucinations
While drifting off to sleep, with my eyes closed, I often see kaleidoscope-like geometric patterns, faces (often grotesque or witch-like), and occasionally swarming insects. They are not dreams, are not perceived as being part of reality or projected into the real visual field, and do not have emotional connotations. I always assumed they were caused by going from visual perception to blank darkness while drifting toward sleep: a sort of meditative optical illusion/visual imagination.
They are called hypnogogic hallucinations and are extremely common, and the particular things I see are commonly seen, along with other stereotyped visuals. (“Stereotyped” as in common to people who experience the phenomenon, as opposed to “unique.”) They are caused, in simple terms, by the visual centers of the brain “idling” before sleep.
Hypnopompic hallucinations are less common, and are more vivid, often briefly perceived as real, often frightening illusions which occur upon waking from sleep. I've had those too, thankfully only a few times; mine were quite unpleasant, full-sensory illusions of being entombed in stone. They were not nightmares, though; I could also see my real surroundings. Once someone in the room with me verified that I had my eyes wide open and could track movement and respond to voices.
I have also sometimes, while wide awake, heard my name being called, when no one is there or when nobody called it. This is also extremely common. People in dangerous situations often hear voices giving helpful commands or suggestions; grieving people often see or hear their loved ones. These phenomena are common and “normal.”
I wish Sacks had analyzed those situations more in neurological terms, because I find that fascinating. The main theory he suggests, regarding auditory hallucinations in general, is that they’re a glitch caused by the brain failing to recognize its own thoughts. Another possibility is that people become consciously aware of the non-verbal stream of consciousness beneath their articulated thoughts, and perceive it as coming from the outside.
Sacks covers a number of hallucinatory experiences caused by neurological conditions, such as Charles Bonnet Syndrome, in which blind people hallucinate certain types of sights. Also, in a fairly funny chapter, his own youthful drug use.
The non-psychotic hallucinations are typically either never experienced as “real,” or are easily believed to be unreal once someone explains that they aren’t real, or are understood to not be real once they’re over. This is quite different from psychotic disorder-type hallucinations, which are often believed to be real, even when they end. (A person with PTSD may hallucinate, but they typically either always know the hallucination isn’t real, or, as in the case with flashbacks, figure it out in retrospect.) Regarding culturally normal hallucinations like ghosts, people may believe that they did literally see a spirit, but they also regard it as a spirit – a visitor from another realm. That’s a different experience from literally believing that Abraham Lincoln is living in your guest bedroom. (To avoid wank, let’s assume that I am only discussing those perceptions of spirits, God, etc, when they really are hallucinated and not objectively real.)
Hallucinations without accompanying delusions don’t usually cause major life problems for people. They are not “crazy,” though they might worry that they are. Delusions seem to be what cause the life problems.
The book is well-written and intriguing, as one would expect from Sacks, but more descriptive than analytical. Some types of hallucinations, particularly visual ones with a clear-cut neurological basis such as migraine auras, are explained in neurological terms, but others are simply described. The descriptions are quite evocative and the material is fascinating, but I would have liked more neurological speculation, especially on why certain situations or conditions create certain types of hallucinations, like fever deliriums causing distorted perceptions of size, which are almost invariably perceived as unpleasant or threatening.
I also wish he’d covered auditory hallucinations in more depth. At times he speculated on historical figures who might have heard voices. The problem is, many people write about the simple perception of their own thoughts in voice-like terms, so it’s very hard to tell whether someone literally meant they heard a voice, or only that their thoughts were so vivid that they seemed voice-like. It seems entirely possible, too, that two different people might have a neurologically identical experience, but one might attribute it to an outside voice and one to distinctive inner thoughts.
Please discuss your own experiences of and theories on hallucinations, if you wish.
Hallucinations
no subject
In short: I suddenly think of what would happen if a mass shooting starts right now/right here, and then for a short time afterwards (and then recurring for several hours after), I imagine myself taking actions to fight back. I know this isn't real; however, like explosions in my mind, entire scenes "happen" and inside my mind I'm having vivid, emotional reactions to the situation. (If I'm alone I may cry and grieve "made up" people's death or heroism, and then perhaps I'll find myself actually crying while doing dishes.)
Often it involves me coming up with weapons in various scenarios one could use to fight back. For instance, if the shooter is armored as in the Aurora case, but this is my office, the letter opener is an example, and I may go for the killer's eyes (which is unimaginably horrifying if thought isn't "forced" on me). In public settings I imagine asking people for "anything sharp."
I'm also the "hero" in this "rehearsal fantasy," which probably serves some psychological purpose for me.
That's the gist of these types of things. I don't think they're quite "hallucinations," but they seem to have the power and force of delusions and involve seemingly independent agents (other victims, the police arriving and I have to surrender, the press, Ann Coulter saying on some show that "imagine what he could have done with a gun", etc.) saying things that "surprise" me and feel like they're coming from outside.
These often lead directly into me writing something fictional. Yesterday's scenario of this sort evolved past being about "me" and evolved into helping me understand the psychology of one of my characters (a female ex-Marine who finds herself in a group of civilians under fire). It helped me relate to her, which I needed.
Anyway, these things fascinate me and I wonder whether there's anything "kind of" like it in the book. To me the MAIN thing going on here seems to be a rehearsal for an imaginary situation that is causing me worry. (Similar to some of my nightmares where I'm fighting zombies, only it seems this is a more realistic fear/concern.)
no subject
Those are very vivid daydreams. It's not a hallucination unless you literally see, hear, or otherwise perceive things as occurring outside of your own mind, and projected into the outside world. Surprising twists in your own scenarios are not the same thing. Similarly, delusions require actual belief in their objective reality, not just a sense that they're vivid or could happen.