Religions throughout the world—and throughout history—have put dreams at the center of their belief systems, and researchers say there's a good reason for that. We do much of our intense dreaming during REM sleep, when the highly active brain acts almost like it's awake, writes Ross Pomeroy at Real Clear Science. All that activity can lead to dreamed situations that feel very real—in some cases, even religious. In a new paper in Frontiers in Psychology, a neurologist and theological scholar argue that dreams are well-suited to create experiences in which we believe we've spoken to a deity of some kind. That is in part due to the feeling of an alternative reality we get in dreams, the researchers say.
What's more, in dreams, we often ascribe emotions and thoughts to those we believe we're encountering. We give them an "exaggerated degree of agency" because our dreaming brains have trouble understanding our thoughts as our own, the researchers write. The researchers also note that unclear boundaries between REM sleep and wakefulness can be linked to schizophrenia—but at Gizmodo, Annalee Newitz notes that the feeling of "hearing voices" may not necessarily mean a person is dealing with mental illness. A recent survey found that 15% of respondents who say they've heard voices have no diagnosis of disorder, and the "hearing" involved isn't necessarily auditory; the voices may not feel as though they're external at all, researchers say. (Researchers last year described schizophrenia as not one, but eight different illnesses.)