Palm reader turned cognitive scientist Ray Hyman wrote:
As we have seen, clients will readily accept stock spiels such as those I have presented as unique descriptions of themselves. Many laboratory experiments have demonstrated this effect. Forer (1948) called the tendency to accept as valid a personality sketch on the basis of the client’s willingness to accept it ‘the fallacy of personal validation.” The early studies on personal validation were simply demonstrations to show that students, personnel directors, and others can readily be persuaded to accept a fake sketch as a valid description of themselves. A few studies tried to go beyond the demonstration and tease out factors that influence the acceptability of the fake sketch. Sundberg (1955), for example, gave the Minnesota Multiphasic Personality Inventory (known as the MMPI) to 44 students. The MMPI is the most carefully standardized personality inventory in the psychologist’s tool kit. Two psychologists, highly experienced in interpreting the outcome of the MMPI, wrote a personality sketch for each student on the basis of his or her test results. Each student then received two personality sketches– the one actually written for him or her– and a fake sketch. When asked to pick which sketch described him or her better, 26 of the 44 students (59 percent) picked the fake sketch!
Sundberg’s study highlights one of the difficulties in this area. A fake, universal sketch can be seen as a better description of oneself than can a uniquely tailored description by trained psychologists based upon one of the best assessment devices we have. This makes personal validation a completely useless procedure. But it makes the life of the character reader and the pseudo psychologist all the easier. His general and universal statements have more persuasive appeal than do the best and most appropriate descriptions that the trained psychologist can come up with.
Full Story: Skeptical Inquirer: Cold Reading: How to Convince Strangers That You Know All About Them
See also: The Forer Effect