Barnum Effect, in psychology, the phenomenon that occurs when individuals believe that personality descriptions apply specifically to them (more so than to other people), despite the fact that the description is actually filled with information that applies to everyone. The effect means that people are gullible because they think the information is about them only when in fact the information is generic. The Barnum Effect came from the phrase often attributed (perhaps falsely) to showman P. T. Barnum that a “sucker” is born every minute. Psychics, horoscopes, magicians, palm readers, and crystal ball gazers make use of the Barnum Effect when they convince people that their description of them is highly special and unique and could never apply to anyone else.
The Barnum Effect has been studied or used in psychology in two ways. One way has been to create feedback for participants in psychological experiments, who read it and believe it was created personally for them. When participants complete an intelligence or personality scale, sometimes the experimenter scores it and gives the participant his or her real score. Other times, however, the experimenter gives participants false and generic feedback to create a false sense (e.g., to give the impression they are an exceptionally good person). The reason that the feedback “works” and is seen as a unique descriptor of an individual person is because the information is, in fact, generic and could apply to anyone.
The other way that the Barnum Effect has been studied is with computers that give (true) personality feedback to participants. Personality ratings given by computers have been criticized for being too general and accepted too easily. Some researchers have done experiments to see if people view actually true feedback as being any more accurate than bogus feedback. People do see actually true descriptions of themselves as more accurate than bogus feedback, but there is not much of a difference.
The Barnum Effect works best for statements that are positive. People are much less likely to believe that a statement applies to them when it is a negative statement, such as “I often think of hurting people who do things I don’t like.” Thus, Barnum Effect reports primarily contain statements with mostly positive items, such as the items listed here. Note that the negative phrases are offset by something positive to end the statement.