Why Extra Sensory Perception Is Not Real

ESP

The term ESP (Extra Sensory Perception) was coined by J.B. Rhine in the 1920s (Blackmore, 2001). Rhine investigated paranormal phenomena while at Duke University. ESP refers to a number of psychic abilities such as telepathy, precognition, clairvoyance (remote viewing), or clairaudience (hearing voices or thoughts psychically). One of the more popular methods to demonstrate that someone has ESP called the Ganzfeld procedure (Bem & Honorton, 1994; Blackmore, 2001).

In the Ganzfeld method one person is a "sender" and another is a "receiver." The sender views randomly chosen pictures or images while the receiver sits a soundproof chamber with their eyes covered, wearing headphones that play continuous white noise, and with a red light shinning in the room. The sender concentrates on the image and the receiver attempts to connect to this image mentally. When ready, the receiver removes the eye covers and picks the image the sender relayed to him from one of four images he is shown. Using this method Bem and Honorton (1994) reported that their subjects produced a hit rate of 33%. Since 25% would be the rate expected by chance the researchers sited this as evidence for ESP. But wait a second! This conclusion is based on a lack of knowledge concerning chance. What was been observed is known as the clustering illusion that commonly occurs in short sequences of random events (Gilovich, 1991). For instance, the probability that a coin toss will turn up heads is 1/2; however, the probability of getting four straight heads in a row is 1/16 which is not very improbable. Moreover, even after getting a string of four heads if one were to keep repeating many sequences of four tosses and averaging the results one would produce results consistent with getting heads 50% of the time. Yet, many would believe that a single string four heads in a row was some sort of "hot streak" that falls outside the realm of chance.

In response to Bem and Honorton's (1994) findings Milton and Wiseman (1999) conducted a meta-analysis of 30 controlled studies from seven different facilities that used the Ganzfeld method. Meta-analysis is considered a more powerful statistical procedure than single study designs because it combines the results of many studies. The results of the meta-analysis failed to confirm that the hit rate in all of these studies was above chance. Moreover, in reanalyzing Bem and Honorton's results it was found that the 33% hit rate was not statistically significant.

Susan Blackmore, a researcher in England who was at first a believer in ESP but after many years of research found no evidence for it, ran a series of controlled studies of the Ganzfeld method (Blackmore, 2001). She never found any evidence for ESP. Her conclusions, along with many others indicate that the research supporting ESP is flawed because: