There's increasing understanding that things like your environment around you when you sleep can really influence those dreams. You can harness that by something called dream engineering. Some people will have very vivid dreams or even have, you know, lucid dreams where they can control what's going on so they could choose to fly. And some people, almost that kind of boundary between sleep and waking is a lot more porous anyway. That's where sometimes you get hypnagogia, but also you get things like sleep paralysis,. which is particularly conducive for certain kind of very scary presence phenomena or presence of hallucination.
Shermer and Alderson-Day discuss the psychologist’s journey to understand the phenomenon of sensed-presence: the disturbing feeling that someone or something is there when we are alone. Using contemporary psychology, psychiatry, neuroscience, and philosophy, Alderson-Day attempts to understand how this experience is possible. Is it a hallucination, a change in the brain, or something else? The journey to understand takes us to meet explorers, mediums, and robots, and step through real, imagined, and virtual worlds.
Ben Alderson-Day is an Associate Professor in Psychology and a Fellow of the Wolfson Research Institute for Health and Wellbeing at Durham University. A specialist in atypical cognition and mental health, his work spans cognitive neuroscience, psychiatry, philosophy, and child development. His new book is Presence: The Strange Science and True Stories of the Unseen Other.