Seeing Spooks

[dalriada]

From the Torygraph, apologies if this has been posted before:


Scientists "see" ghosts
By Roger Highfield, Science Editor
Last Updated: 7:01pm GMT 21/02/2008


The reason that apparitions, bogeymen and phantoms like to lurk in the shadows may have been revealed by scientists. A team from University College London finds that when we gaze around in a poorly-lit context, it can fool our brains into seeing things that are not really there.

Although no one has done a systematic study of ghosts*, neuroscientists are convinced they are "all in the mind" and, in the light of the new work, it does not seem so surprising that they seem most often glimpsed in "spooky" dimly-lit circumstances In the journal PLoS Computational Biology, Prof Li Zhaoping and her colleagues say that the context surrounding what we see is all important - sometimes overriding the evidence gathered by our eyes and even causing us to imagine things. They were surprised to find that a vague background context has more influence on what we see than one that is bright and well defined, and speculate that this might explain the power of some abstract art and why we can see vivid details in the vague brush strokes of impressionist paintings.

"The paintings are vague in details, but I speculate that, perhaps because of this vagueness viewers are free to use their vivid imaginations to fill-in the details," says Prof Zhaoping, who adopts her first name as her scientific pen name - Li is such a common name it can cause an identity crisis for Chinese scientists.

"Everything we see is an hallucination generated by the virtual reality machine inside our head," comments Prof Mike Morgan of The City University, London. "Normally these hallucinations are vetoed by the information coming through our senses, so we can call perception 'controlled hallucination.But when the input is ambiguous we can see all sorts of things, like the faces de Quincy saw in clouds and carpets. There are hundreds of faces hidden in the textured floors of the platforms at Euston Underground Station, if you look for them."

To reveal the haunting power of context, 18 observers were asked by the UCL team to concentrate on the centre of a black computer screen. Every time a buzzer sounded they pressed one of two buttons to record whether or not they had just seen a small, dim, grey 'target' rectangle in the middle of the screen. It did not appear every time, but when it did appear it was displayed for just 80 milliseconds (80 one thousandths of a second).

"People saw the target much more often if it appeared in the middle of a vertical line of similar looking, grey rectangles, compared to when it appeared in the middle of a pattern of bright, white rectangles. They even registered 'seeing' the target when it wasn't actually there," says Prof Zhaoping. "This is because people are mentally better prepared to see something vague when the surrounding context is also vague. It made sense for them to see it - so that's what happened. When the target didn't match the expectations set by the surrounding context, they saw it much less often.

"Illusionists have been alive to this phenomenon for years,"continues Prof Zhaoping. "When you see them throw a ball into the air, followed by a second ball, and then a third ball which 'magically' disappears, you wonder how they did it. In truth, there's often no third ball - it's just our brain being deceived by the context, telling us that we really did see three balls launched into the air, one after the other. Contrary to what one might expect, it is a vague rather than a bright and clearly visible context that most strongly permits our beliefs to override the evidence and fill in the blanks."

This could also be why monsters tend to lurk in shadows. "In shadows many things are seen vaguely (rather than clearly), thus tending to trigger the filling-in," says Prof Zhaoping.


http://www.telegraph.co.uk/earth/main.jhtml?view=DETAILS&grid=&xml=/earth/2008/02/21/scighost121.xml

[bobdezon]

Wonder what Dr B makes of this?

[Dr B]

It's interesting stuff - but nothing new. We have a strange situation at the moment with a lot of para-scientists nicking stuff from mainstream cognitive science and just re-doing it with the paranormal or even mainstream people using the paranomral to make their research look more 'funky'.

It is important to do - but not that new or insightful (more deductive than inductive in the sense it confirms what we already know). Like I said, I think it should be done - but in the context of everything that has gone before.....8) Anticipatory biases and contexutal effects on perception have been investigated for decades and are well documented. Anyone here remember the flea circus?

I wonder if they used an SDT (signal detection theory paradigm) to tease out sensitivity and response bias? I am sure they did though I have yet to read the primary article.

[Admin]

Not much to disagree with there but I do think the analogy of using one's imagination to fill in the details of paintings is somewhat misleading.

When we see, or rather perceive, a 'spook', the process of converting an ambiguous stimulus into a perception is an automatic process rather than an active one; similar in manner to how we perceive optical illusions.

[bobdezon]

I totally agree with the autonomy of the process John.

Dr B, do you not feel that paranormal investigators who use scientific methods to determine if there is indeed any paranormal phenomena, and publish good solid results, are in someway still silly because of what they seek in the first place?

I must admit I would have thought the scientific community would at least give a nod in the direction of the groups who act like this. It saves the scientists a whole bunch of headaches reexplaining what has been explained to be natural before.

[Mulder]

Dr B, do you not feel that paranormal investigators who use scientific methods to determine if there is indeed any paranormal phenomena, and publish good solid results, are in someway still silly because of what they seek in the first place?

It's 'not Dr B' here! What sort of results are we talking about here? Is it people trying to use scientific methods to demonstrate the paranormal or natural explanations? In my experience, groups who attempt to demonstrate the paranormal scientifically rarely understand either science, instruments or logic. They seem to think if you take a few readings it somehow makes it scientific.

[bobdezon]

It's 'not Dr B' here! What sort of results are we talking about here? Is it people trying to use scientific methods to demonstrate the paranormal or natural explanations? In my experience, groups who attempt to demonstrate the paranormal scientifically rarely understand either science, instruments or logic. They seem to think if you take a few readings it somehow makes it scientific.

Like I said, good scientific results. Evidence to explain why the phenomena isnt paranormal, based on actual scientific replicable facts, like the maligned orb theory. Im not advocating that groups who use scientific equipment are in any way scientific. Measuring enviromental readings with devices made to measure such, does not make anyones findings "scientific". Lets face facts here, if we discount anecdotal evidence, and stress or mental illness reasons, medication or susbstance abuse, or missattributation of phenomena, there is ZERO evidence of the paranormal. If a paranormal group claims to have evidence of such then they better have some solid scientific proof to back that claim. I have yet to see a single shred of evidence provided by any paranormal group that proves that any aspect of the paranormal is real.

[Mulder]

In that case, no I definitely DON'T think groups are silly to use scientific methods to invesigate the paranormal. Can't speak for DrB, of course ...!

While the existence of the paranormal is debatable, that people continue to report similar phenomena year after year is not. It is certainly, in my opinion, something worthy of scientific investigation. Even if there is no obvious evidence of the paranormal, there is certainly evidence of something!

[bobdezon]

I personally believe much if not all of it is the result of primative instinct, possibly a variation of a survival instinct, and possibly cognative processes that are misunderstood by the person experiencing it. Imagination does seem to play a large part in the retelling of the tale.

[Mulder]

I personally believe much if not all of it is the result of primative instinct, possibly a variation of a survival instinct, and possibly cognative processes that are misunderstood by the person experiencing it. Imagination does seem to play a large part in the retelling of the tale.

With respect, I'm not interested in what anyone believes about the paranormal. I want to KNOW, which is why I believe science is the way forward.

[dalriada]

What sort of results are we talking about here? Is it people trying to use scientific methods to demonstrate the paranormal or natural explanations? In my experience, groups who attempt to demonstrate the paranormal scientifically rarely understand either science, instruments or logic. They seem to think if you take a few readings it somehow makes it scientific.


The most recent edition of the Journal of the Society for Psychical Research Vol 72.1 Number 890 January 2008 just dropped in my mailbox today.

Exhibit A is an article by some bloke from Birmingham entitled "Putting Magnetism in its Place: A Critical Examination of the Weak-Itensity Magnetic Field Account for Anomalous Haunt-type Experiences" pp 34- 50. The paper discusses the neuromagnetic field theory, assesses its biophysical plausibility and its limitations, concluding that although the magnetic field account has much to commend it, it is neither uncontroversial nor comprehensive in its current form.

The paper has four-and-a-bit pages worth of references...


Exhibit B is on the following pages 51-57, a research note entitled "An Acoustic Research InfraSound Detector (ARID). It is pointed out that both that name and the associated abbreviation are copyright of the authors Parsons & O'Keefe (2006) who declare an "underlying purpose of making infrasound research accessible to paranormal investigators". The article is a "technical description of a highly efficient reference instrument, a workable infrasound detection and measurement system."*

Eight references are also given in support.

[dalriada]

Oh..and just in case it is actually possible to copyright single words, I want first dibs on wankers and bollocks...

They're my favourites...

>:D

[Mulder]

So, Dalriada, are you agreeing with my point or disputing it? I'm really not sure ...

[dalriada]

Agreeing that there are indeed two ways of looking at hauntings:

A) science, logic, reasoning
and
B) taking a few readings...*

[Mulder]

In my opinion, for what it's worth, I think far more ghosts are explained by misperception than electromagnetic fields or infrasound. I always thought it extremely unlikely that someone could turn a mundanely caused shadow into a ghostly figure, complete with full details of non-existent 'limbs' and 'clothing', until I saw it happen!

When someone tells me they've seen a ghost, and describe it in huge detail, I'm not as impressed as I used to be.

[bobdezon]

With respect, I'm not interested in what anyone believes about the paranormal. I want to KNOW, which is why I believe science is the way forward.


I also believe science is the only way to determine if what people are experiencing is real or not (not necessarily paranormal either) It would be our best chance of actually knowing anything about the subject with any degree of certainty. I am also very interested in why people report such phenomena, and what the actual underlying causes are (again not necessarily paranormal)

[bobdezon]

In my opinion, for what it's worth, I think far more ghosts are explained by misperception than electromagnetic fields or infrasound. I always thought it extremely unlikely that someone could turn a mundanely caused shadow into a ghostly figure, complete with full details of non-existent 'limbs' and 'clothing', until I saw it happen!

When someone tells me they've seen a ghost, and describe it in huge detail, I'm not as impressed as I used to be.


I do not subscribe to the point of view such phenomena is even possible. It may be possible in a lab with the correct, meticulously constructed enviromental variables, but even if huge magnetic fields can cause hallucinations, the levels of magnetism are generally far far less than is required at the location of the alleged haunting/sighting. So while this is an interesting pursuit, it doesnt help paranormal researchers as the enviromental baselines are not the same.

I think the infrasound research is also interesting, but seeing gray blobs out of the corner of your eye, does not mean it is possible to see headless horsemen or any other type of typical or archetypal ghost or phenomena. Feelings of unease etc do not make a ghost. There must be another reason for it.

[dalriada]

There's some great stuff, written in very engaging style, in Phantoms in the Brain: Human Nature and the Architecture of the Mind (http://www.amazon.co.uk/Phantoms-Brain-Human-Nature-Architecture/dp/1857028953) by V.S. Ramachandran...

One of the best books I've read in a very long time..

O0

and a PS re the "seeing things" line of discussion..I have absolutely shocking eyesight without contact lenses. As I am way too vain to wear glasses, if for some reason I can't wear lenses I wander around in a fuzzy world of swirly colours unable to even see my own hand in front of my face...After a few hours though, those swirly shapes start to resolve themselves fairly quickly into what seem as "real things" spiders out of the corner of my eye, golden halos about people's heads etc...but these disappear instantly once I have my lenses back. If I was living deep in "woo-culture" I might easily attribute these misperceptions to all sorts of mystical reasons-and argue about it vigorously after all, I'm not mad or on medication, and I really do see them...

I wonder if that's what made me skeptical? I literally don't believe my eyes..

[dalriada]

An interesting review ofthe Ramachandran book is available here (http://ajp.psychiatryonline.org/cgi/content/full/157/5/841)

[Mulder]

I do not subscribe to the point of view such phenomena is even possible. It may be possible in a lab with the correct, meticulously constructed enviromental variables, but even if huge magnetic fields can cause hallucinations, the levels of magnetism are generally far far less than is required at the location of the alleged haunting/sighting. So while this is an interesting pursuit, it doesnt help paranormal researchers as the enviromental baselines are not the same.

The fields required to produce hallucinations (EIFs - experience inducing fields) are actually extremely modest (a few hundred nanotesla). The significant factors are that they must vary (between 0.1 and 30 Hz) and do so in a complex way (ie. not just regular sine waves). People must be exposed to them for around 20 mins and only around 25% of the population are susceptible.

Thus, the magnetic environment is not going to be that unusual in a domestic situation filled with all sorts of electrical and electronic appliances. If you look at http://www.apaw71.dsl.pipex.com/MADS/ you will see that a suitable environment has already been found at one haunted location.


I think the infrasound research is also interesting, but seeing gray blobs out of the corner of your eye, does not mean it is possible to see headless horsemen or any other type of typical or archetypal ghost or phenomena. Feelings of unease etc do not make a ghost. There must be another reason for it.

That's the point I was making about misperception. It sounds ridiculous that someone can turn an amorphous shape into a ghostly figure in full detail but it happens.

Everyone, whether they are interested in ghosts or not, is fully aware of them through TV, films, books, video games and reports in the media (fiction and non-fiction). So, when they see something unfamiliar, their brain will try to understand it using the closest memory they have in their experience, even if it is fictional. Since the act of seeing is primarily a function of the brain, with the eye only one contributor to the experience, people can sometimes interpret poorly seen visual stimuli as something quite different, with the detail added 'to fit' by their brain. You get the same thing in witness reports of real incidents where details are added that were never there in the first place.

[bobdezon]

The fields required to produce hallucinations (EIFs - experience inducing fields) are actually extremely modest (a few hundred nanotesla). The significant factors are that they must vary (between 0.1 and 30 Hz) and do so in a complex way (ie. not just regular sine waves). People must be exposed to them for around 20 mins and only around 25% of the population are susceptible.

Thus, the magnetic environment is not going to be that unusual in a domestic situation filled with all sorts of electrical and electronic appliances. If you look at http://www.apaw71.dsl.pipex.com/MADS/ you will see that a suitable environment has already been found at one haunted location.

Muncaster castle? Yes Im aware it has unusual naturally occuring magnetic fluctuations. I read the papers by Dr B, seems interesting. I just dont see how the majority of home reported sightings can be attributed to EIF's, if the EIF relies on a complex modulation of the waves due to faulty wiring etc, one would think electricians would be aware of all this overloaded and faulty wiring, it seems to cause less problems than one would think it would. I can find no data to suggest 25% of the population is susceptible to the hypersensitivity of magnetic fields that induce hallucination.




That's the point I was making about misperception. It sounds ridiculous that someone can turn an amorphous shape into a ghostly figure in full detail but it happens.

Everyone, whether they are interested in ghosts or not, is fully aware of them through TV, films, books, video games and reports in the media (fiction and non-fiction). So, when they see something unfamiliar, their brain will try to understand it using the closest memory they have in their experience, even if it is fictional. Since the act of seeing is primarily a function of the brain, with the eye only one contributor to the experience, people can sometimes interpret poorly seen visual stimuli as something quite different, with the detail added 'to fit' by their brain. You get the same thing in witness reports of real incidents where details are added that were never there in the first place.

I totally agree with you on this point, these are exactly my thoughts on the matter too. We experience as a whole rather than on individual points and I believe its possible to just build a picture we recognise so we can file the experience away as a recognisable memory. The combination of misunderstood or missatributed phenomena combined with our primative survival instinct could generate a manufactured "complete image" of what we witnessed. However that doesnt really explain how two people can see the exact same thing at the same time if exposed to the same anomalous phenomena. We would be building our own recognisable image, it could not be a shared experience. The accounts would differ slightly unless we were both exposed to exactly the same life and experiences.

[Mulder]

Muncaster castle? Yes Im aware it has unusual naturally occuring magnetic fluctuations. I read the papers by Dr B, seems interesting. I just dont see how the majority of home reported sightings can be attributed to EIF's, if the EIF relies on a complex modulation of the waves due to faulty wiring etc, one would think electricians would be aware of all this overloaded and faulty wiring, it seems to cause less problems than one would think it would. I can find no data to suggest 25% of the population is susceptible to the hypersensitivity of magnetic fields that induce hallucination.

Firstly, it's not naturally occuring fluctuations at Muncaster. Rather the bed at the centre of the experiences is permanently magnetised. This creates a steep magnetic gradient around the bed. Anyone moving in this area would thus induce magnetic fluctuations in their own head simply by virtue of moving it through the gradient (rather than fields having to fluctuate).

Secondly, EIFs do not require faulty wiring (though such cases may occur). Many ordinary electrical appliances produce significant magnetic fields by virtue of their operation, particularly those using motors. The combination of such fields can produce the required complexity (see http://www.assap.org/newsite/articles/Magnetic%20ghosts.html) and field strength in a domestic or work place environment.

Thirdly, the 25% comes from Persingers work. The susceptibility Persinger refers to is that of the temporal lobe. Also, please don't confuse this with 'electrical hypersensitivity', which is generally thought to be psychosomatic (see http://en.wikipedia.org/wiki/Electrical_sensitivity) and completely irrelevant here.

[Mulder]

However that doesnt really explain how two people can see the exact same thing at the same time if exposed to the same anomalous phenomena.

You cannot know that two people saw exactly the same thing. They probably saw something very similar, since it was produced by the same ambiguous stimulus.

If they agree completely it could be that they conferred about their experience (which almost certainly happened when they were together) and effectively synchronised their story.

If they don't agree completely then that would be the same as if they had both seen a real person briefly. With both the ghost and the real person, they both saw the same visual stimulus but remembered, and forgot, different details.

[bobdezon]

Firstly, it's not naturally occuring fluctuations at Muncaster. Rather the bed at the centre of the experiences is permanently magnetised. This creates a steep magnetic gradient around the bed. Anyone moving in this area would thus induce magnetic fluctuations in their own head simply by virtue of moving it through the gradient (rather than fields having to fluctuate).

I read that the sensor A (pillow area) had a lower reading than the sensor B (window area) the sensor B area registered at 77857nt. A considerable difference. If the bed is wooden, I dont understand how it can emit such a magnetic field.


Secondly, EIFs do not require faulty wiring (though such cases may occur). Many ordinary electrical appliances produce significant magnetic fields by virtue of their operation, particularly those using motors. The combination of such fields can produce the required complexity (see http://www.assap.org/newsite/articles/Magnetic%20ghosts.html) and field strength in a domestic or work place environment.

Well in a typical home you have a washing machine, dryer, video recorder etc all with rotary motors, yet these also occur in properties where these are not present. If Im reading this correctly its requires a specific modulation range to work. This is usually lower than its normal operating frequency.


Thirdly, the 25% comes from Persingers work. The susceptibility Persinger refers to is that of the temporal lobe. Also, please don't confuse this with 'electrical hypersensitivity', which is generally thought to be psychosomatic (see http://en.wikipedia.org/wiki/Electrical_sensitivity) and completely irrelevant here.


Persinger? oh the god helmet bloke. Susan blackmore was impressed by that, but dawkins was not. I suppose until there is more work done on this by others, I will have to use the data provided. I do not believe electrical hypersensitivity exists, I believe it to be totally psychosomatic. When I said hypersensitivity to magnetic fields I did not mean electrical hypersensitivity.

[bobdezon]

You cannot know that two people saw exactly the same thing. They probably saw something very similar, since it was produced by the same ambiguous stimulus.

If they agree completely it could be that they conferred about their experience (which almost certainly happened when they were together) and effectively synchronised their story.

If they don't agree completely then that would be the same as if they had both seen a real person briefly. With both the ghost and the real person, they both saw the same visual stimulus but remembered, and forgot, different details.


I am referring to a personal experience of mine, I was very careful to not mention what I had seen before I described what I had seen to the other person. I know this is possible because I was a witness to it, and I am critical even of myself. I fully understand how conferring can lead to universal agreement even when it is possible we could have seen entirely different things. I wanted an accurate description of events, not a complete agreement. The description provided by this person was accurate in every detail to mine, yet I had not informed this person of what I had seen I merely asked "did you see that" which is very ambigous. I was very careful to question at length my version of events with the other persons. They were an exact match, even down to specific colours.

[Dr B]

There is a lot to respond to here (some confusions above) and some nice points made by Mulder & Dalriada O0

I will try to go through the points as best i can across a number of posts over the next day or so.

Suffice to say here that there are some major misunderstandings over the role of EMFs in general (as well as some confusions above) in this area of study, and the role for infrasound appears non-existant. The power of suggestion is far from an explanation - but i will comment more on this later. Note - concentrating on one factor (i.e., EMFs) in a study is not an argument against the role of other factors - so dont fall into that trap!!!!

Back soon.....

[Dr B]

Not much to disagree with there but I do think the analogy of using one's imagination to fill in the details of paintings is somewhat misleading.

When we see, or rather perceive, a 'spook', the process of converting an ambiguous stimulus into a perception is an automatic process rather than an active one; similar in manner to how we perceive optical illusions.

There are two issues here. The early acting bottom-up processes of grouping and pattern-matching are automatic and are clearly involved. But there are top-down factors as well like anticipation, expectation, prior-knowledge etc which can add biasing signals to information processing at the mid-vision level (and beyond) – so it is not necessarily the case that all these effects are purely driven by bottom-up automatic factors alone.

As I said much earlier an SDT paradigm may help in this regard to some small extent – but properly controlled experiments designed to measure the contributions of all these factors, under different contexts, are needed. I have unpublished evidence from my lab that the bottom-up processes are identical across individuals (skeptics and believers) and across both vision and auditory processes – but top-down modulatory biasing signals and response biases are not matched between these groups. This suggests that the predisposition is not located in early sensory cortex and brain areas.

[Dr B]

Dr B, do you not feel that paranormal investigators who use scientific methods to determine if there is indeed any paranormal phenomena, and publish good solid results, are in someway still silly because of what they seek in the first place?
Certainly not and I am not sure why anyone would think that. :undecided:


I must admit I would have thought the scientific community would at least give a nod in the direction of the groups who act like this.
They do, have, and have always……so I’m not sure what the mystery is here….? ???

[Dr B]

It's 'not Dr B' here! What sort of results are we talking about here? Is it people trying to use scientific methods to demonstrate the paranormal or natural explanations? In my experience, groups who attempt to demonstrate the paranormal scientifically rarely understand either science, instruments or logic. They seem to think if you take a few readings it somehow makes it scientific.

I totally agree with you on this. The woo's have a theoretically-laden and somewhat theoretically-loaded approach that makes most of what they do - unsound.

[Dr B]

I have yet to see a single shred of evidence provided by any paranormal group that proves that any aspect of the paranormal is real.

Me neither O0 However, if we simply try to set out to 'understand' the phenomena rather than make it fit our loaded positions then this is the best way forward.

It's not about proving or disproving anything and anyone using that approach is not being truly scientific. It is about gaining a functional understanding of the mechanisms to such an extent that we no longer need to ask why or how. At this point - our model (and hence our understanding) is explicit enough O0

[Dr B]

While the existence of the paranormal is debatable, that people continue to report similar phenomena year after year is not. It is certainly, in my opinion, something worthy of scientific investigation. Even if there is no obvious evidence of the paranormal, there is certainly evidence of something!

This is the essence of the most useful approach I think. We still need answers for the experiences - just not paranormal ones (if indeed they ever qualify as answers :cheesy:)

[Dr B]

The most recent edition of the Journal of the Society for Psychical Research Vol 72.1 Number 890 January 2008 just dropped in my mailbox today.

Exhibit A is an article by some bloke from Birmingham entitled "Putting Magnetism in its Place: A Critical Examination of the Weak-Itensity Magnetic Field Account for Anomalous Haunt-type Experiences" pp 34- 50. The paper discusses the neuromagnetic field theory, assesses its biophysical plausibility and its limitations, concluding that although the magnetic field account has much to commend it, it is neither uncontroversial nor comprehensive in its current form.

The paper has four-and-a-bit pages worth of references...


Exhibit B is on the following pages 51-57, a research note entitled "An Acoustic Research InfraSound Detector (ARID). It is pointed out that both that name and the associated abbreviation are copyright of the authors Parsons & O'Keefe (2006) who declare an "underlying purpose of making infrasound research accessible to paranormal investigators". The article is a "technical description of a highly efficient reference instrument, a workable infrasound detection and measurement system."*

Eight references are also given in support.


;D;DO0

Interesting stuff O0 However, why would paranormal research be interested in infrasound when it has never been shown to have an effect on inducing hallucinations and inducing anomalous perceptions?

In other words - why measure something that's irrelevant?

[Dr B]

In my opinion, for what it's worth, I think far more ghosts are explained by misperception than electromagnetic fields or infrasound. I always thought it extremely unlikely that someone could turn a mundanely caused shadow into a ghostly figure, complete with full details of non-existent 'limbs' and 'clothing', until I saw it happen!


I agree - but would add that we don't need an explantion - we need a host of them as it is a multi-dimensional issue where lots of factors are likely to co-vary across instances.

[Dr B]

More to follow later........;)

[Cuddles]

I agree - but would add that we don't need an explantion - we need a host of them as it is a multi-dimensional issue where lots of factors are likely to co-vary across instances.

I think this is probably the most important point and it's one that either doesn't occur to, or is ignored by, the vast majority of believers in the paranormal. People always ask "What is the explanation for ghosts?" or UFOs or whatever. The point is, there isn't one. There are lots. For some phenomena there are probably as many causes as there are sightings, while for others there may be just a few common causes.

Sleep paralysis, for example, is a very good explanation for a lot of ghost and alien sightings. The objection is usually then raised "But that can't explain my story.", usually with the implication that therefore ghosts are real. Sure, it might not be able to explain a specific sighting, but that just means that there are other causes as well, not that sleep paralysis isn't the cause of many sightings.

I would tend to agree with Bobdezon that magnetic fields can't possibly explain the vast majority of ghosts. However, that doesn't mean it's a pointless area to look at, since if even a tiny minority of cases are caused by this, that makes some cases that can't be explained in any other way. Even if it turns out that magnetic fields can't explain any sightings at all, the effects of magnetic fields on the brain and how and why they have those effects can be pretty interesting stuff all by itself.

[Mulder]

I read that the sensor A (pillow area) had a lower reading than the sensor B (window area) the sensor B area registered at 77857nt. A considerable difference. If the bed is wooden, I dont understand how it can emit such a magnetic field.

The bed has an iron mesh supporting the mattress.


Well in a typical home you have a washing machine, dryer, video recorder etc all with rotary motors, ... If Im reading this correctly its requires a specific modulation range to work. This is usually lower than its normal operating frequency.

The important operating frequency is not the mains frequency but the rotary frequency of the motors. The motor consists of magnets rotating bits of metal, frequently steel. That is where the important fluctuating magnetic fields are coming from. Persinger uses rotating fields in some of his experiments.


.. yet these also occur in properties where these are not present ...

Assuming you're referring to ghosts, yes I agree. You may remember that a long time ago I said I thought EIFs were probably only responsible for a small number of ghost reports. Ghosts have lots of different causes, EIFs are only one!

[Mulder]

I am referring to a personal experience of mine, I was very careful to not mention what I had seen before I described what I had seen to the other person. I know this is possible because I was a witness to it, and I am critical even of myself. I fully understand how conferring can lead to universal agreement even when it is possible we could have seen entirely different things. I wanted an accurate description of events, not a complete agreement. The description provided by this person was accurate in every detail to mine, yet I had not informed this person of what I had seen I merely asked "did you see that" which is very ambigous. I was very careful to question at length my version of events with the other persons. They were an exact match, even down to specific colours.

Very commendable way to handle the situation. However, you'd have to disclose the full circumstances of the experience before I could possibly comment. I am always being told impressive sounding experiences that become less so on closer inspection. I'm not saying this is the case here but I'm just explaining why full details are always necessary.

[Dr B]

I do not subscribe to the point of view such phenomena is even possible. It may be possible in a lab with the correct, meticulously constructed enviromental variables, but even if huge magnetic fields can cause hallucinations, the levels of magnetism are generally far far less than is required at the location of the alleged haunting/sighting. So while this is an interesting pursuit, it doesnt help paranormal researchers as the enviromental baselines are not the same.


I think this is quite wrong. Firslty, the lab studies establish the premise of a neural response (and an experiential one in some cases) to the application of such fields. Now, I have a number of problems with the lab studies and have outlined these in a recent article - so i won't repeat them here. However, enough prima-facia evidence suggests that there is possibly an effect to be had. To refute this would require you to come up with a plausible explanation for those effects in the lab and the multiple independent field-based studies that have produced data in line with the predictions. Not impossible - but it must be done to maintain the view. I should point out that i am skeptical of the claims for very very weak fields and geomagnetic fields (say <100nT) - but effects from much stronger complex fields look promising.

Secondly, it has nothing to do with huge magnetic fields per-se - it is more related to time-based complexity (though obviosuly some energy is needed). Think of the immediate enviornment having an epileptic fit and what those waveforms would look like. It's just a metaphor but it is important people understand no one has ever made the claim for high-strength magentic fields and anomalous cognition.

I think the point about baselines is also confused.



I think the infrasound research is also interesting, but seeing gray blobs out of the corner of your eye, does not mean it is possible to see headless horsemen or any other type of typical or archetypal ghost or phenomena. Feelings of unease etc do not make a ghost. There must be another reason for it.

That's odd - i think that research is fundamentally flawed in that infrasound (true-infrasound that is) has never been shown to have effects on perception. Have you got some experimental data on this where the study used true-infrasound and not just low-frequency sound of a high-amplitude? Otherwise, what's so interesting about it?

[Dr B]

Muncaster castle? Yes Im aware it has unusual naturally occuring magnetic fluctuations. I read the papers by Dr B, seems interesting. I just dont see how the majority of home reported sightings can be attributed to EIF's, if the EIF relies on a complex modulation of the waves due to faulty wiring etc,

Who ever said it did? Not me. I have never ever said this at all and would suggest you read the papers again. It's simple - those papers look at one factor and one factor alone implicated ONLY in one set of experiences (the core TR bed experiences) this has always been made explicit. None of my work suggests it is a common mechanism or even a likely one in most cases - in fact one of my recent papers argues strongly against that interpretation.

It's a common mistake banded about and I know one researcher from 'up north' who likes to propogate that myth - its known around here as a 'straw man' O0




I can find no data to suggest 25&#37; of the population is susceptible to the hypersensitivity of magnetic fields that induce hallucination.


I am not sure I agree with these exact figures - however, Persinger does get a response from more of his sample and stronger responses from those scoring higher on neural instability scales. Others get effects on neurons with epileptics (Jon Dobson) - though this involves the application of simple-form mid-intensity fields



However that doesnt really explain how two people can see the exact same thing at the same time if exposed to the same anomalous phenomena.

And when has this ever really happened? ??? Are there any truly convincing published studies of this? You may be searching for an explanation here for something which does not exist.O0

[Dr B]

I read that the sensor A (pillow area) had a lower reading than the sensor B (window area) the sensor B area registered at 77857nt. A considerable difference. If the bed is wooden, I dont understand how it can emit such a magnetic field.


If you go back and read the paper you will see it refers to the bed support mesh - which is metal and is distorting the field. This is fully explained in that paper and all the others that followed it. It is important to pay attention to this detail. 8)



Persinger? oh the god helmet bloke. Susan blackmore was impressed by that, but dawkins was not.

Wrong - Dawkins had a severe headache afterwards. Not a strange experience - but potentially a neural response. So its not entirely true to say he was not impressed. btw - the phenomena of nausea, headaches, vivid dreams etc - occuring after the sessions is common to Persigner's method (apparently) - though you will need to read through a good deal of his work to see that.



I suppose until there is more work done on this by others, I will have to use the data provided. I do not believe electrical hypersensitivity exists, I believe it to be totally psychosomatic.

This is demonstrably false - what you really mean here is that you have not read the work by people like, Cook, Dobson, Fuller, Bell, etc showing effects of mid-intensity mag fields on epileptic brains, only when those fields were applied. This has nothing to do with psychosomatic effects. I do think Persinger gets a lot of people now coming along and experiencing what they expect and i do think there is a lot of suggestion and sensory deprivation effects in his tests (he usually gets a high false-alarm rate). The question is whether you think that explains all of the effect and his statistics, at times, suggest otherwise.

You will need to read his stuff closely to spot this.

(PS - dont get me wrong - I am well skeptical of a good deal of Persinger's work - but in different ways and for different reasons)

[Dr B]

Hi Cuddles

Some great points and one or two below O0



I would tend to agree with Bobdezon that magnetic fields can't possibly explain the vast majority of ghosts.

The problem is no one here really says it can so it becomes something of a straw man point (at least in relation to my position - though possibly not to others). In some papers Persinger hints that the amplitudes he uses are around the levels of a hair-dryer or electric razor - the implication is that the field strengths are commonly available. So I think he is 'hinting' here at some degree of commonality. However, even if the fields were common (and i am not convinced they are) that does not mean - at least to me - that the effect is commonly available as it is dependent on other factors as well that limit its applicability.

What Persinger's work suggests is the possibility of a non-induction based coupling mechanism between weak, complex magnetic fields and the human brain - under certain circumstances only. I reckon those circumstances are very rare - however, when they occur they may be the some of the most striking experiences of all.

Persinger hints they might be common but you will struggle to push him on it and he provides no data / estimations on it. He is rather clumsy on this point.



However, that doesn't mean it's a pointless area to look at, since if even a tiny minority of cases are caused by this, that makes some cases that can't be explained in any other way.

I totally agree - and i think this is my position on the matter - it's very very rare.....My point is - like i said much earlier - showing that mag fields can be implicated in some experiences does not in anyway negate other explanations for other experiences or even multiple factors being involved in concert.....



Even if it turns out that magnetic fields can't explain any sightings at all, the effects of magnetic fields on the brain and how and why they have those effects can be pretty interesting stuff all by itself.
Absolutely!!!

[bobdezon]

Certainly not and I am not sure why anyone would think that. :undecided:

Excellent O0


They do, have, and have always……so I’m not sure what the mystery is here….? ???

Ive had so many arguments with people who are professional scientific types who often think they very nature of the experiments are useless simply because they believe it cannot exist. I keep tell them that is just bias and cynicism but they refuse to budge on this. I think they just dont like the thought of being derided by their colleagues.


Me neither O0 However, if we simply try to set out to 'understand' the phenomena rather than make it fit our loaded positions then this is the best way forward.

I concur. O0


It's not about proving or disproving anything and anyone using that approach is not being truly scientific. It is about gaining a functional understanding of the mechanisms to such an extent that we no longer need to ask why or how. At this point - our model (and hence our understanding) is explicit enough O0

Yes again I totally agree, without a correct model to promote the functionality and understanding, it means nothing at all. Its like giving highly technical information to a stone age people.

Anyway very tired now, no sleep last night, both kids awake all night terrified of the wind ;D Ill try and finish my replies tommorow when Ive had a decent kip. Good thread this. O0

[bobdezon]

The bed has an iron mesh supporting the mattress.

Might be interesting to see if the results differ if the mattress was removed.


The important operating frequency is not the mains frequency but the rotary frequency of the motors. The motor consists of magnets rotating bits of metal, frequently steel. That is where the important fluctuating magnetic fields are coming from. Persinger uses rotating fields in some of his experiments.

I wonder if this effect can be established to be the cause of the hallucinations though? I would imagine people working in a location like a building site would be in direct contact with many of these fields for most of the working day. Infact I read the other day some builder claimed hed seen a UFO and we were about to be invaded, maybe this was the cause ;D


Assuming you're referring to ghosts, yes I agree. You may remember that a long time ago I said I thought EIFs were probably only responsible for a small number of ghost reports. Ghosts have lots of different causes, EIFs are only one!

Yes I agree with your position that it may be responsible for some effect on perception. There are bound to be many other reasons too.


Very commendable way to handle the situation. However, you'd have to disclose the full circumstances of the experience before I could possibly comment. I am always being told impressive sounding experiences that become less so on closer inspection. I'm not saying this is the case here but I'm just explaining why full details are always necessary.

Well I have some experience at researching this type of thing so I know how to be careful, especially as there are bias at work, if it is yourself who is the subject. I posted about my odd experience a while back, I found the thread for you.

http://www.skeptics.org.uk/forum/showpost.php?p=21496&postcount=39

[bobdezon]

;D;DO0

Interesting stuff O0 However, why would paranormal research be interested in infrasound when it has never been shown to have an effect on inducing hallucinations and inducing anomalous perceptions?

In other words - why measure something that's irrelevant?

I read that Vic Tandy experienced odd grey blob like hallucinations while in his lab, was this effect never replicated by other researchers?
If this is true, and there has been no replication, then I would have to agree with it being useless as a potential explanation for some types of phenomena :undecided:


Who ever said it did? Not me. I have never ever said this at all and would suggest you read the papers again. It's simple - those papers look at one factor and one factor alone implicated ONLY in one set of experiences (the core TR bed experiences) this has always been made explicit. None of my work suggests it is a common mechanism or even a likely one in most cases - in fact one of my recent papers argues strongly against that interpretation.

:sad: I said that, I did not assert you claimed that in your report. It doesnt seem to be your style. Maybe you read that as a run on sentance? I ramble when I wax lyrical ;D


It's a common mistake banded about and I know one researcher from 'up north' who likes to propogate that myth - its known around here as a 'straw man' O0

Hmmm I think I know whom your referring to here, although his interest is not magnetic field based (if im thinking of the same person)


I am not sure I agree with these exact figures - however, Persinger does get a response from more of his sample and stronger responses from those scoring higher on neural instability scales. Others get effects on neurons with epileptics (Jon Dobson) - though this involves the application of simple-form mid-intensity fields

Never heard of neural instability scales, I had no idea such a scale existed. What is its purpose, and what exactly does it measure? The title seems ambigious to me. ???


And when has this ever really happened? ??? Are there any truly convincing published studies of this? You may be searching for an explanation here for something which does not exist.O0

Well I dont know about published reports (in scientific journals) but I did have something similar happen to myself at one point. I did request you to try and provide an explanation at the time IIRC, Im not aware if youve read the thread though, maybe you missssed it. The link I provided above for Mulder if you have time to have a quick look. Ive spent years trying to explain it, nothing fits though (that Im aware of) It makes me feel uncomfortable knowing I cant solve the puzzle.


If you go back and read the paper you will see it refers to the bed support mesh - which is metal and is distorting the field. This is fully explained in that paper and all the others that followed it. It is important to pay attention to this detail. 8)

I concur. O0


Wrong - Dawkins had a severe headache afterwards. Not a strange experience - but potentially a neural response. So its not entirely true to say he was not impressed. btw - the phenomena of nausea, headaches, vivid dreams etc - occuring after the sessions is common to Persigner's method (apparently) - though you will need to read through a good deal of his work to see that.

I dont know about the headaches afterwards,he didnt seem impressed when I watched him on Horizon. He said (of the experience) "I would be hard put to it, to swear. That those where not things that could happen to me anytime, on a dark night". He seemed quite blase about it.

http://www.youtube.com/watch?v=Y_-txbHNyOY


This is demonstrably false - what you really mean here is that you have not read the work by people like, Cook, Dobson, Fuller, Bell, etc showing effects of mid-intensity mag fields on epileptic brains, only when those fields were applied. This has nothing to do with psychosomatic effects. I do think Persinger gets a lot of people now coming along and experiencing what they expect and i do think there is a lot of suggestion and sensory deprivation effects in his tests (he usually gets a high false-alarm rate). The question is whether you think that explains all of the effect and his statistics, at times, suggest otherwise.

You will need to read his stuff closely to spot this.

(PS - dont get me wrong - I am well skeptical of a good deal of Persinger's work - but in different ways and for different reasons)

I was referring to people who claim they are electrosensitive, and they feel ill around mobile phone towers and can tell if your mobile phone is switched on etc, not people who have epilepsy etc. I have no data available to me that would suggest this is a real phenomena.

[Dr B]

Ive had so many arguments with people who are professional scientific types who often think they very nature of the experiments are useless simply because they believe it cannot exist. I keep tell them that is just bias and cynicism but they refuse to budge on this. I think they just dont like the thought of being derided by their colleagues.


That's a real shame and I would have the same opinion as you when encountering such attitudes O0.

My point is, I can investigate OBEs without any notion of paranormality (for example). Indeed, this is eaxctly what I do. Investigating these experiences does not imply that one buys into the suggested nonsense that surrounds them. One does not follow from the other.

I have to say I have not really met a serious scientist that has those views. Most I talk to can see the merits - but can also see the pitfalls as well. This appears to be a relatively balanced view. Maybe we are talking to different 'types' of scientist - as most of my colleagues are not parapsychologists or notable skeptics :undecided: (indeed, nor am I)

[Dr B]

Might be interesting to see if the results differ if the mattress was removed.

The mattress has no effect whatsoever. We have surveyed the bed with it removed. We have also surveyed five separate baseline beds (four-poster beds ranging from the 15th - 17th Century) - with no such patterns. They all have a mattress.



I wonder if this effect can be established to be the cause of the hallucinations though? I would imagine people working in a location like a building site would be in direct contact with many of these fields for most of the working day. Infact I read the other day some builder claimed hed seen a UFO and we were about to be invaded, maybe this was the cause ;D


I am not so sure about everything that Mulder is suggesting - but one thing to keep in mind is that it is not simply the case of being exposed to these fields and 'hey presto' you have an experience. Levels of arousal, attention, context, stimulation, and susceptibility are also important - as they are for many behavioural effects. 8)



Yes I agree with your position that it may be responsible for some effect on perception. There are bound to be many other reasons too.


I think what both Mulder and I are saying is that there are many reasons and this is just one ???

[Dr B]

I read that Vic Tandy experienced odd grey blob like hallucinations while in his lab, was this effect never replicated by other researchers? If this is true, and there has been no replication, then I would have to agree with it being useless as a potential explanation for some types of phenomena :undecided:

Indeed. In fact it's even worse than that. The theory proposed by Tandy appears to be based on an utterly flawed premise and the suggested biophysics appear, at least at present, to be highly unlikely. Did you know that all infrasound experiments appear to use low-frequency sound of high amplitude? This means - its just sound (of high energy) and can be heard. How is this supposed to reveal a mechanism for inaudible air vibrations?

My position on infrasound is this. IAV is unlikely to engage with the brain in any meaningful manner. It's just too weak. However, low-frequency sound can be heard and misattributions from this (in the right context) could lead to anomalous reports. However, let's be clear - this is not what Tandy suggested and this does not require a new biophysical explanation. It is also not infrasound - it's sound!



Never heard of neural instability scales, I had no idea such a scale existed. What is its purpose, and what exactly does it measure? The title seems ambigious to me. ???


Thought not. Clinicians use them to establish aura content in epileptic patients - but they have been adapted for parapsychologists. Persinger has one (TLE instability questionnaire - the PPI) but other measures appear more reliable (other quesitonnaires). Things like compulsive daydreaming, deja-vu, Jamis-vu, misattributions of familiarity, a sensed presence, hearing voices etc are all part of a neural instability continuum. Some measures like the revised LSHS, AEI, DES, and CAPS have dissociative subscales linked to temporal lobe instability. People who score high on these - are easier to stimulate with magentic fields.



I did request you to try and provide an explanation at the time IIRC, Im not aware if youve read the thread though, maybe you missssed it.

I'm not aware of this - but i often get bombarded with such requests and I simply don't have the time to wade through them all....:-[




I dont know about the headaches afterwards,he didnt seem impressed when I watched him on Horizon.

I read his report on the BBC website - and he discussed his headache there.....



I was referring to people who claim they are electrosensitive, and they feel ill around mobile phone towers and can tell if your mobile phone is switched on etc, not people who have epilepsy etc. I have no data available to me that would suggest this is a real phenomena.

This health stuff is bogus and has nothing to do with what we are discussing here. It's best not to confuse them.O0 I agree with you about the dodgy nature of that work - but its utterly irrelevant to effects on perception.

[bobdezon]

The mattress has no effect whatsoever. We have surveyed the bed with it removed. We have also surveyed five separate baseline beds (four-poster beds ranging from the 15th - 17th Century) - with no such patterns. They all have a mattress.

Ok now Im confused, if the iron in the mattress is not influencing the magnetic field, what is it in muncaster that exerts the influence around the bed? was the source traced?


I am not so sure about everything that Mulder is suggesting - but one thing to keep in mind is that it is not simply the case of being exposed to these fields and 'hey presto' you have an experience. Levels of arousal, attention, context, stimulation, and susceptibility are also important - as they are for many behavioural effects. 8)

I concur that would have to be true, different combinations of expectation ect would have a remarkedly different result on a test base of volunteers.


I think what both Mulder and I are saying is that there are many reasons and this is just one ???

That I can agree with.


Indeed. In fact it's even worse than that. The theory proposed by Tandy appears to be based on an utterly flawed premise and the suggested biophysics appear, at least at present, to be highly unlikely. Did you know that all infrasound experiments appear to use low-frequency sound of high amplitude? This means - its just sound (of high energy) and can be heard. How is this supposed to reveal a mechanism for inaudible air vibrations?

I have no idea, is that even possible?


My position on infrasound is this. IAV is unlikely to engage with the brain in any meaningful manner. It's just too weak. However, low-frequency sound can be heard and misattributions from this (in the right context) could lead to anomalous reports. However, let's be clear - this is not what Tandy suggested and this does not require a new biophysical explanation. It is also not infrasound - it's sound!

Sounds reasonable to me.


Thought not. Clinicians use them to establish aura content in epileptic patients - but they have been adapted for parapsychologists. Persinger has one (TLE instability questionnaire - the PPI) but other measures appear more reliable (other quesitonnaires). Things like compulsive daydreaming, deja-vu, Jamis-vu, misattributions of familiarity, a sensed presence, hearing voices etc are all part of a neural instability continuum. Some measures like the revised LSHS, AEI, DES, and CAPS have dissociative subscales linked to temporal lobe instability. People who score high on these - are easier to stimulate with magentic fields.

Thanks for the explanation. O0 I must admit I have never heard of Jamis-vu :sad:


I'm not aware of this - but i often get bombarded with such requests and I simply don't have the time to wade through them all....:-[

I understand, I just thought maybe there was a logical reason for it. You being a cognative neuroscientist might know the explanation for it. Id like to think its something incredibly simple so I can kick myself for not having considered it ;D


I read his report on the BBC website - and he discussed his headache there.....

Didnt see that unfortunately.


This health stuff is bogus and has nothing to do with what we are discussing here. It's best not to confuse them.O0 I agree with you about the dodgy nature of that work - but its utterly irrelevant to effects on perception.

I concur, I suppose if they had different names we would not use them so interchangeably, this would avoid confusion. ;D

[Dr B]

Ok now Im confused, if the iron in the mattress is not influencing the magnetic field, what is it in muncaster that exerts the influence around the bed? was the source traced?


I thought you said you read the paper ;)? It's the metal mesh bed support under the mattress (part of the bed) - it has nothing to do with the mattress - i don't think I ever suggested anywhere it was a mesh in the mattress.....:cheesy:

The source is traced - its the mesh in the bed!!!



I have no idea, is that even possible?


I dont think anything to do with infrasound being argued for by the late Mr Tandy is possible.



Thanks for the explanation. O0 I must admit I have never heard of Jamis-vu :sad:


You are most welcome - it is not as frequent as deja-vu, but it does happen O0

[bobdezon]

I thought you said you read the paper ;)? It's the metal mesh bed support under the mattress (part of the bed) - it has nothing to do with the mattress - i don't think I ever suggested anywhere it was a mesh in the mattress.....:cheesy:

The source is traced - its the mesh in the bed!!!

Yes I read it, but I thought the metal mesh was the one inside the mattress, you know the bed of springs thing. Not the actual support for the mattress ;D

[Dr B]

Hiya Bob

Sorry if it was confusing - but no, it has nothing to do with the mattress. Have a good weekend O0

[FarSideOfTheMoon]

This is probably a bit OT, but is there any record of people recounting strange experiences after having MRI scans?

Just to add my experiences of seeing or feeling things....I've had a couple of MRI brain scans and the feeling of claustrophobia and the associated noise is a bit off-putting but that is about it. I've had a couple of sleep paralysis incidents where I've felt presences in the room. I had one when I was younger when I had the feeling of falling and something just pure evil beside me. The second one, I felt something evil was sitting on a chair in my room, and they way I hung my clothes on the chair that particular night did make me think there was something or somebody sitting there.

Even more OT, I also get migraines every few weeks with quite severe visual disturbances,everything goes a bit blurry - it gets to the stage where I can't make out text on the tv etc. But I can't ever see how these particular type of visual disturbance could lead someone to think they have seen a ghost or whatever.

This is a very interesting thread so far though!

[Admin]

This is probably a bit OT, but is there any record of people recounting strange experiences after having MRI scans?

Not to my knowledge.

The difference is that MRI scans use a very powerful but fairly static (once aligned) magnetic fields whereas Experience Inducing Fields (EIFs) can be quite low power but change through time in a complex manner.

It's the complexity of the field that's they key to EIFs rather than the strength of the field.

[Dr B]

Exactly! It's all about complexity in the EIFs more than strength per-se. However, if you move your participant into the scanner too fast (via the electronic bench they lie on) - they can get dizzy and suffer nausea due to a rapid change in the background field (but again, as John notes above, its still down to a complexity issue - not a strength one per-se).

If you slow down the entry rate into the scanner the effects are elminated (though the same strength is there) and indeed this is now recommended. O0

[Dr B]

Even more OT, I also get migraines every few weeks with quite severe visual disturbances,everything goes a bit blurry - it gets to the stage where I can't make out text on the tv etc. But I can't ever see how these particular type of visual disturbance could lead someone to think they have seen a ghost or whatever.

This is a very interesting thread so far though!

Aha.....I know a bit about this as i worked with migraine patients as an undergraduate and did some research assistant work in this area. My then supervisor (the late Ed Chronicle) was an expert on this (see the work by Chronicle and Palmer).

It seems that Migrainers who typically suffer from aura (visual disturbances) do have less inhibited corticies - but only in V1 (the earliest part of the primary visual cortex). This has been attributed to either - fewer GABA inhibitory neurons or (more likely in my opinion), the same number of neurons, just than many of them have become dysfunctional or no longer work. This can give you something of a super-power!!!! Oh yes, these people can see visual stimuli at temporal thresholds well below the rest of us - but before you go out an buy an X-man suit - it comes with a cost - that cost is aura, visual discomfort, and possibly even the migraine itself.

The evidence for this comes from three main strands of research. One is behaviorual research where migrainers (with aura) can perform what is known as a meta-contrast masking task at speeds far in excess to the rest of us (the super power I mentioned above). In other words they can detect the target stimulus accurately, long aftert the rest of us start to perform at chance. These experiments were done using SDT and show that its not a response bias - but an issue of perceptual sensitivity.

Another strand is psychopharmacological - where certain GABAergic drugs do not enjoy a great deal of uptake in V1 - suggesting fewer GABA neurons - or fewer neurons working correctly.

A final strand of evidence comes from TMS (transcranial-magnetic stimulation) where migrainers require a much reduced amplitude of magnetic field in order to induce phosphenes and othe visual disturbances - which again suggests a lack of inhibitory regulation.

Make sense?O0

[FarSideOfTheMoon]

Not really, I think you lost me after 'Aha....' ;)

[jamiefox]

eh you dont have to be in poor light to see ghosts, what about seeing people in the corners of our eyes,,i see people where i work in the corner of my eyes, and in certain areas,mainly places where if there was really someone there they could walk away and hide from veiw,

im not a beliver but would like this to be explained to,

[jamiefox]

i wonder if having wi-fi in your house could affect your brain,,many people still think wireless gadgets can affect the brain,,

[Dr B]

i wonder if having wi-fi in your house could affect your brain,,many people still think wireless gadgets can affect the brain,,

No - there is no evidence to back this up and it is a completely different form of EMF - totally unlike the complex low-frequency fields used by Persinger etc.

[Mulder]

eh you dont have to be in poor light to see ghosts, what about seeing people in the corners of our eyes,,i see people where i work in the corner of my eyes, and in certain areas,mainly places where if there was really someone there they could walk away and hide from veiw,

im not a beliver but would like this to be explained to,

Try these links: http://www.assap.org/newsite/articles/Misperception.html

and http://www.assap.org/newsite/articles/Corner%20eye%20phenomena.html

Ghosts have been seen in plain daylight, however that does not mean they are paranormal.