Science offers helfpul tools to test the claims of many psychics. However, it is much more difficult, if not impossible, to test in the laboratory those who claim they have the ability to contact the dead. Many mediums claim that they do not control the willingness of spirits to talk through them. Furthermore, they also assert that the spirits are less willing to speak when skeptics are near.

For their part, skeptics claim that mediums perform what is known as a "cold reading"; that is, they ask questions of the subjects ("fishing" for information) and pick up on and respond to verbal and nonverbal clues. In other words, most of the information in the reading is provided by the subject, not the medium. The critics assert that mediums make vague comments regarding the deceased, often referring to a month or a number or a letter...