In this thread:
https://boards.straightdope.com/sdmb/showthread.php?t=851769
most people were applying Occam’s Razor and Newton’s Flaming Lazer Sword to say that since scientific evidence connects physical activity in the brain to mental states we call consciousness, that what we call “our self” expires with brain death. I mentioned the phenomenon of shared hallucinations, of which there are numerous anecdotes online, as something which might throw off such analysis. I agree scientific studies of the phenomenon are necessary to consider it for that debate. So, can anyone point to any positive or negative results on whether shared hallucinations actually occur in scientific literature?
Huh.
A hallucination is a perception by the brain of sensory inputs that have no external cause. By definition, there is no such thing as a “shared hallucination”. “Anecdotes online” have the same factual weight as people seeing visions of angels or ghosts, or talking to a “god”, i.e. none.
Stranger
Yeah, I realized I spelled laser wrong within the edit time window but let it slide (I even know what laser is an acronym for). I am not sure what Stranger means in his “by definition” reply.
Ok, Stranger did an edit which clarifies. I agree with Stranger, which is why I am asking about scientific studies. I do know scientists were doing studies on the effects of LSD and other hallucinogens (not all with the subjects’ consent, i.e. MKULTRA) in the past. I did some reading about it a few years ago, but forgot the details in regards to shared hallucinations (if that was ever an exact focus).
I don’t know how you could even perform an objective scientific study about a phenomenon that exists strictly within the subjective mind of an individual. I don’t mean that as a flippant remark; the challenge of understanding what is actually going on in the mind, versus just measuring gross metrics of functional brain performance, is a major problem in cognitive science with no clear solution. Functional magnetic resonance imaging (fMRI) was considered to be a groundbreaking tool in cogsci when it was first developed but many researchers have found the value of it dubious in really understanding brain function at the level of even collections of millions of neurons simply because it does not have adequate resolution (not to mention the practical problem of trying to stimulate specific thought patterns or affective responses in a subject stuck in an MRI chamber).
Subjects may report similar hallucinatory experiences which could be based upon either functional similarities in brain function or a prior shared experience which provides the nucleus for a “shared” experience, but without any objective data or plausible mechanism it doesn’t provide any evidence that there is actually communication between brains required for a shared hallucination.
Studies on the effects of lysergic acid diethylamide (LSD) are largely crap simply because researchers have to rely upon perception of subjects which are often influenced by the very questions researchers ask them or the researchers interpretations. Researchers do know a fair amount about the specific mechanism of LSD (act as agonists stimulating the serotonin 5-HT2A receptor subtype). How specficially it produces different sensory hallucinations and why it varies from person to person are very poorly understood because we have only a very poor understanding of brain function at the level of individual neurons and how that influences perceptive cognition.
Stranger
When I first read the OP, I thought you were talking about mass hysteria. But with your mention of LSD, now I don’t know what you mean by “shared hallucination”. If two people are in the same room, partaking of a hallucinogenic substance and communicating with each other, it’s not surprising that there might be some similarity in their experiences. Is that what you mean? I also don’t see what connection any of this has with consciousness after death.
Stranger, what about an experiment in which subjects are placed in seperate, adjacent soundproof rooms. They are randomly given hallucinogens or a placebo (maybe some get different hallucinogens than others). They write down what they experienced before coming into contact again with the other subjects. For good measure: make sure none of the subjects have even met before. And maybe even screen out similar favorite popular culture movies, songs, etc. Look for common elements in the reported hallucinations.
Well, I think you have an elevator pitch for a proposal to NIMH or some private sponsor. Load up on acid tabs, head over to Esalen with the best collection of subjects you can find, and go to town. I’m not sure how you apply some objective critieria in evaluating the similarity between subjective experiences particularly given that eyewitnesses of a physical event often report dramatically different and frequently wrong observations, and good luck with replication, but like Jesse Pinkman says, “It’s Science, bitches!”
Stranger
Jim Peebles, is there a point behind your question? If two people have similar experiences, at least according to some definition of similar, what have we learned?
Besides – “Look for common elements in the reported hallucinations.” – Highly subjective.
That is a side issue. Maybe I shoudn’t have provided the background about that debate. My point there was a shared hallucination would point to an aspect of reality not due to the physical world or the subject’s own neurons firing. If there is such an aspect, then the prevailing argument there would seem to break down. But let’s not derail this thread. Here I an just interested in reading about scientific studies done on shared hallucinations.
It’s also possible that a hallucinogenic drug might, by nature of the drug, always produce hallucinations which meet some particular description. If, for instance, one had a drug which made certain cones in the retina hypersensitive, then that drug might cause everyone who took it to perceive the room as turning blue. The fact that everyone reports the same thing might then tell you something interesting about the drug, but it wouldn’t tell you anything at all about the nature of the room.
Agreed. But I know of numerous examples where scientists pressed on despite similar issues. Here is a relevant example: “Quantitative Analysis of Narrative Reports of Psychedelic Drugs”
Maybe the actual answer is “Some things you can test, other things are not testable but cool to think about as long as you don’t waste too much time doing so”.
Or not.
But if you’re sure you can’t test reliably, then the correct reaction is to say “Heh. Interesting.” And to go do something else.
In my experience, full-blown hallucinations are not common after ingesting LSD, psylocibin, or peyote.
I offer the following experience. It is definitely hallucinogenic since it corresponds to no objective reality, happens to many people (including me) many times and there is pretty general agreement what it looks like: migraine auras. See Migraine - Wikipedia, although Wiki does not mention that these auras occur quite often without the headaches (thankfully, that is my situation). I just read the first volume of Phillip Pullman’s Dust in which the 11 year old protagonist suffers these attacks at random times in the story and the description is essentially identical to my experience.
Hey, you’re not this Jim Peebles Jim Peebles - Wikipedia, are you? A good friend of mine from Winnipeg went to U. Man. with him.
No, that isn’t me. What I am talking about is different from migraine auras. Search for shared hallucinations on google, and read some anecdotal reports to get an idea. Two or more people on the same drug see the same very specific thing. I suspect most of these people are not lying/exaggerating. In search of a “scientific” eplanation, I think the most likely (only?) is that it operates like deja vu. One person sees something and says “Hey did you see X”. Then the other people hallucinate it before they consciously process the words. This is one of many reasons for a scientific study. The lack of scientific studies at all, even negative ones is alarming. It seems it would be one of the first things you would think to try. Perhaps they are all classified because they led to positive results.
But again, even if shared hallucinations tell us something, what do they tell us about? By definition, they’re not telling us something about the world we’re perceiving, because if they were, they wouldn’t be hallucinations. All they can tell us about is what’s causing the hallucinations, be it migraines, drugs, sleep deprivation, or whatever, and what effect those things have on the brain.
Chronos, I argue it would tell us there are aspects of reality that are not physical objects detectable by scientific instruments, and also not just in a single person’s mind. This would throw off the assumptions behind the prevailing argument in the debate which motivated this literature search. (But is a side issue to this thread.)
But if the phenomenon is only observed in human brains, then how can you rule out the possibility that it’s a property of human brains that you’re observing?