The author Michael Prescott, whose often writes on his blog on the subjects of NDE and mediumship, wrote an article that looks at the subject of super-psi. Super-psi refers to the ability of the subconscious mind to get information about people and events in past and the future somehow to give the impression that the information actually comes from the spirit world, through the medium. The idea of super-psi is a way to explain the mediumship without actually involving the spirit world, supposing that it doesn’t exist.
Prescott argues in the article that the super-psi explanation is actually much less probably than the more parsimonious explanation of actual contact with dead relatives. Here’s what the super-psi subconscious has to do to “cover-up” for a real mediumship:
Our unconscious, then, would have the ability (actually or potentially) to reach at will into other minds, regardless of how widely scattered they might be, and even if the minds in question belong to total strangers, people of whose existence we were and are consciously unaware. Moreover, our unconscious would have the ability to perceive, through clairvoyance, information unknown to any living person, peeking into hidden places without restriction and virtually instantaneously, on demand. It has even been hypothesized that the unconscious could peer back in time (retrocognition) or gaze into the future (precognition) in order to obtain additional information. And all of this extraordinary power would be deployed in the service of a charade – the illusion of communication with a specific deceased personality that has, in reality, ceased to exist. Even the medium herself would have not the slightest idea that her unconscious mind was carrying on this amazing deception on a colossal scale.
But since the evidence for anomalous information received through mediums in many cases appears to be strong, Prescott argues, then the survival of consciousness after death appears to be the only probably explanation, given that super-psi is even more improbable.
I suggest you all go and read the article and its almost 50 high-quality comments yourself.