While he attends to his rats, Persinger gives me the lowdown on the haunt theory. Why would a certain type of electromagnetic field make one hear things or sense a presence? What’s the mechanism? The answer hinges on the fact that exposure to electromagnetic fields lowers melatonin levels. Melatonin, he explains, is an anti-convulsive; if you have less of it in your system, your brain —in particular, your right temporal lobe— will be more prone to tiny epileptic-esque microseizures and the subtle hallucinations these seizures can cause.