Creepy. Via Wikipedia:
The God Helmet was not specifically designed to elicit visions of God, but to test several of Persinger’s hypotheses about brain function. The first of these is the Vectorial Hemisphericity Hypothesis, which proposes that the human sense of self has two components, one on each side of the brain, that ordinarily work together but in which the left hemisphere is usually dominant.
Persinger argues that the two hemispheres make different contributions to a single sense of self, but under certain conditions can appear as two separate ‘selves’. 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 …