Magnetic fields, Hallucinations & the Haunt-type Experience: Part I - Background
Growing evidence from laboratory research suggests that the application of weak, complex, low-frequency magnetic fields to the human brain can induce sympathetic shifts neural activity and have consequences for cognition and awareness (see Persinger & Koren, 2001; for a recent review). The net effect of this interaction can be a magnetically induced altered-state of awareness often resulting in complex hallucinations. The likelihood of this occurring is improved if individuals show an increased degree of neural instability (i.e., brain damaged patients, Epilepsy patients, Migraine patients) that is the result of a dysfunction in inhibitory brain processing. Applied to the natural setting, what this suggests is that some spontaneous reports of apparitions and haunt-type phenomena may indeed be a naturally occurring magnetically induced delusion or hallucination. For this theory to be a viable account for spontaneous haunt-type experiences, such complex fields should be present, measurable and quantifiable, in some cases of reputed haunting. The MADS was developed to scientifically test this prediction in the natural setting.
Magnetic fields, Hallucinations & the Haunt-type Experience: Part II
Although the suggestion of complex magnetic fields is one possible account, it is not the only account for spontaneous strange experience. It is important to acknowledge that magnetic fields themselves are not the only variable with the potential to influence perceptions in observers. Many other physical dimensions and contextual factors may contribute and even predominate in certain cases. Therefore, one should not expect to find complex fields in every case of a reputed haunting. Other neurological and psychological factors including, (i) belief systems, (ii) prior suggestion, (iii) expectation, anticipation and demand characteristics, (iv) experiential context and suggestive surroundings, (v) attentional biases, (vi) interpreting signals from noise and ambiguity, (vii) semantic associative processing, (viii) neural disinhibitory processes (partial complex seizures in Epilepsy, Migraine with aura, etc), - to name but a few, could also be crucial. In addition, other environmental and contextual factors such as, (i) lighting levels (ii) temperature / drafts (iii) acoustics, (iv) room / area size and layout, have also been known to impact on perceptions and feelings (Wiseman, Watt, Greening, Stevens, & O'Keeffe, 2002; Wiseman, Watt, Stevens, Greening, & O'Keeffe, 2003). Therefore, failure to find magnetic fields in a single case of a haunting is not convincing evidence against the account (though a failure for all researchers to ever find these fields would be). The magnetic fields hypothesis is only one potential account for these experiences, under certain circumstances, and is certainly not responsible for all experiences. Clearly, some reports need no magnetic component to them at all (see above).
However, initial research should reveal a reasonable a-priori case for why complex magnetic fields may be implicated in specific cases and not others. Our research is starting to suggest that particularly vivid, striking, and sustained haunt-reports, that can be said to have occurred to a number of direct eye-witnesses, in relatively localised places, are more likely to have a magnetic component to them. Fleeting ‘corner-of-the-eye’ phenomena and misperceptions of noise are likely to have completely alternative natural explanations for them. Finally, what might be very interesting for future research is to ascertain how such magnetic fields interact with other factors like, visual context of buildings and rooms etc, to induce haunt-type experiences in susceptible individuals. For example, magnetic fields may induce heightened neural activity in observers, but it may be the immediate experiential context that guides the experiential content and the content of the resulting haunt-type experience.
Magnetic fields, Hallucinations & the Haunt-type Experience: Part III - Summary
Based on the background information discussed above, the suggestion is that locations associated with repeated instances of haunt-type experiences may contain magnetically remarkable environments within them (Braithwaite, 2004; Braithwaite, Perez-Aquino, & Townsend, 2005; Braithwaite & Townsend, 2005; Wiseman, et al., 2003; see Persinger & Koren, 2001). Under certain circumstances these locations, and specific areas within them, may influence neural / experiential processes in certain susceptible individuals. The net result of exposure to such magnetic fields could be that observers may subsequently bias their impressions of ambiguous stimuli in the immediate context towards a paranormal interpretation (see Houran, 2000; Lange & Houran, 2001, 1997), or indeed such fields may induce more elaborate forms of direct sensory hallucination (see Persinger & Koren, 2001). In addition, magnetic fields are likely to interact with other variables available in the immediate microenvironment.
What is both necessary and sufficient for a magnetic field to have experience inducing properties?
Although there are unlikely to be any hard and fast rules here (due to the fact that such fields interact with other complex neuronal properties and other environmental factors that can also vary greatly), exactly how magnetic fields go from the experientially benign to potentially having stimulatory properties is not clear. One suggestion is that the field must be both spatially and temporally inhomogeneous so that a brain cannot habituate to a uniformed constant background variation. One way to define a ‘complex field’ is to flip the question and ask what a ‘simple field’ is. Here a basic static field (DC) or a simple sine wave (AC) would constituent a simple field and thus have no consequences for cognition or awareness at typical environmental amplitudes. However, the presence of any inhomogeneity, over space and / or time and the field moves towards a potentially neurologically active one. The bare minimum factors for a magnetic field to become endowed with such capacity remain unclear.
What are the biophysics of the interaction between weak complex magnetic fields and neuronal processes?
Complex weak magnetic fields do not interact with neural processes in the way simple high-amplitude fields do. A technique known as Trans-cranial Magnetic Stimulation (TMS) uses simple magnetic pulses (in the Tesla region) to induce instant and specific effects in neural responses. It does this by employing a pulse, so intense, that it induces immediate responses in neurons (depolarisation resulting in action potentials) which then impacts on cognitive processing (see, Walsh, & Pascual-Leone, 2003). The biophysics of this process are reasonably well known. A magnetic field in the Tesla region is very unlikely to ever be present in the normal environment and so could not be responsible for haunt-type reports and hallucinations. However, this mechanism is totally unlike that which results from exposure to weak complex magnetic fields. This procedure is known as Trans-Cerebral Stimulation (TCS: see Persinger & Koren, 2001) and its effects build up over time (an observer needs to be exposed to such fields for a prolonged period of time and the effects are more diffuse). This likely reflects a different mechanism of interaction between magnetic field and neural processes than that seen for TMS.
Are there any experiential differences between haunt-reports where a magnetic component has been identified relative to those where it has not?
This is a tantalising question that remains unanswered. One reason for this is that the appropriate technology needed to demonstrate the presence of crucial magnetic anomalies has not been available. With the development of MADS, this is no longer the case. This now becomes an important question for future research. It could be that experiences elicited by magnetic anomalies involve more or less senses (vision / audition etc), or that they are more or less vivid, more or less prolonged, or differ in actual content and emotional meaning to the observer. It may be that there are no differences at all. Either way, this is an important question to be addressed in the future.
Do magnetic fields interact with other factors? If so, what are these other factors and what processes underlie the interaction?
In the natural setting magnetic fields do not occur in isolation. It may well be the case that such fields interact with other factors related to the individual (such as increased neural instability) and the environment (such as suggestive features in the immediate environment / context, i.e., in a reputedly haunted old castle, or sources of ambiguous stimuli). These other factors may be sufficient on their own in some cases and for some observers, but when coupled to the presence of complex magnetic anomalies, the chances of an anomalous report may well increase.
How common is the magnetic-field account for haunt-type reports likely to be?
This is unclear. It is certainly NOT the case that all or even most haunt-type reports will reflect a magnetic anomaly. Indeed some of the other suggestions outlined above are far more prevalent in the natural setting. Some notable instances of magnetic anomalies have been documented in both a modern haunting (Persinger & Koren, 2001; Persinger, Koren, & O'Connor, 2001; though this also involved experiences from a brain-damaged patient) and a classic case of a reputedly haunted castle (Braithwaite, 2004, in press; Braithwaite, Perez-Aquino, & Townsend, 2005; Braithwaite & Townsend, 2005). The nature and sources of the magnetic fields involved were quite distinct in both cases. Nevertheless, it is unlikely that the magnetic account is a common occurrence in haunt-type reports (though a useful estimate remains unspecified). The explanation for any particular haunting does not become a ‘paranormal’ one simply due to the absence of any magnetic anomalies for that case.
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