Original sentence: It may also involve physical phenomena such as materilizations.Mediumship usually involves communication between a human instrument and one or more discarnate, spirit personalities.Skeptics say that mediumship is the result of self-delusion, unconscious influence, or of  magician's techniques such as cold reading and hot reading
Edited sentence: In skepticism, mediumship is considered to be the result of self-delusion, unconscious influence, or of  magician's techniques such as cold reading and hot reading.It is thought that a medium can communicate with the spirits of the dead