Hallucinations Are Everywhere (2018)

And that, according to the psychologist Philip Corlett, is what makes a hallucination. But Corlett operates on the idea that hallucinations exist within a hierarchy. A survey in the early 1990s found that 10 to 15 percent of the population of the United States experienced vivid sensory hallucinations at some point in their lives.

Source: www.theatlantic.com