[1] Reports by participants of a "sensed presence" while wearing the God helmet brought public attention and resulted in several TV documentaries.
Persinger and Koren designed the God Helmet in an attempt to create conditions in which contributions to the sense of self from both cerebral hemispheres is disrupted.
The second experimental hypothesis was that when communication between the left and right senses of self is disturbed, as they report it is while wearing the God Helmet, the usually-subordinate 'self' in the right hemisphere intrudes into the awareness of the left-hemispheric dominant self,[22] causing what Persinger refers to as "interhemispheric intrusions".
[23] Persinger theorises that many paranormal experiences,[24] feelings of having lived past lives,[25] felt presences of non-physical beings,[26] ghosts,[27] muses,[28] and other "spiritual beings", are examples of interhemispheric intrusions (an idea originally proposed in 1976 in Julian Jaynes' bicameral mentality hypothesis).
[33] The purpose of exposing magnetic fields patterned after neurophysiological sources, such as the burst-firing profile of the amygdala, is to enhance the probability of activating the structure from which the signal was derived.
[35] The acoustic chamber is also a Faraday cage,[33] shielding out all EMF emissions and radiation except the Earth's magnetic field.
[38] In contrast, Persinger's apparatus uses weak complex magnetic signals patterned after physiological processes, such as one derived from limbic burst firing.
[7] Persinger explained Dawkins' limited results in terms of his low score on a psychological scale measuring temporal lobe sensitivity.
"[45] In December 2004 Nature reported that a group of Swedish researchers led by Pehr Granqvist, a psychologist at Uppsala University in Sweden, had attempted to replicate Persinger's experiments under double-blind conditions, and were not able to reproduce the effect.
[10] Granqvist et al concluded that the presence or absence of the magnetic field had no relationship with any religious or spiritual experience reported by the participants, but was predicted entirely by their suggestibility and personality traits.
Other groups have subsequently found that individual differences such as strong belief in the paranormal and magical ideation predict some alterations in consciousness and reported "exceptional experiences" when Persinger et al's experimental set-up and procedure are reproduced, but with a sham "God helmet" that is completely inert or a helmet that is turned off.
One experiment found no changes in emotional responses to photographs whether the device was on or off,[50][18] Persinger and colleagues report significant changes in subjects' EEG during stimulation with a Shakti system.
The study found that reports of unusual experiences were unrelated with the presence or absence of "complex" environmental electromagnetic fields similar to Persinger's.