thumb|259x259px|Bertram Forer
The Barnum effect, also called the Forer effect or, less commonly, the Barnum–Forer effect, is a common psychological phenomenon whereby individuals give high accuracy ratings to descriptions of their personality that supposedly are tailored specifically to them, yet which are in fact vague and general enough to apply to a broad range of people. This effect can provide a partial explanation for the widespread acceptance of some paranormal beliefs and practices, such as astrology, fortune telling, aura reading, and some types of personality tests. Psychologist Paul E. Meehl coined the term "Barnum effect" in 1956 in his essay "Wanted – A Good Cookbook", because he relates the vague personality descriptions used in certain "pseudo-successful" psychological tests to those given by showman P. T. Barnum.
Overview
The Barnum effect is manifested in response to statements that are called "Barnum statements", meaning that general characterizations attributed to an individual are perceived to be true for them, even though the statements are such generalizations that they could apply to almost anyone. Such techniques are used by fortune tellers, astrologers, and other practitioners to convince customers that they, the practitioners, are in fact endowed with a paranormal gift. The effect is a specific example of the "acceptance phenomenon", which describes the general tendency of humans "to accept almost any bogus personality feedback". A related and more general phenomenon is that of subjective validation.
Early research
In 1947, psychologist Ross Stagner asked a number of personnel managers to take a personality test. After they had taken the test, Stagner, instead of responding with feedback based on their actual individual answers, presented each of them with generalized feedback that had no relation to their test answers but that was, instead, based on horoscopes, graphological analyses, and the like. Each of the managers was then asked how accurate the assessment was. More than half described the assessment as accurate, and almost none described it as wrong.
In 1948, in what has been described as a "classic experiment", psychologist Forer gave a psychology test – his "Diagnostic Interest Blank" – to 39 of his psychology students, who were told that they would each receive a brief personality vignette based on their test results. One week later Forer gave each student a purportedly individualized vignette and asked each of them to rate it on how well it applied. In reality, each student received the same vignette, consisting of the following items:
On average, the students rated its accuracy as 4.30 on a scale of 0 (very poor) to 5 (excellent). Only after the ratings were turned in, it was revealed that all students had received an identical vignette assembled by Forer from a newsstand astrology book. The effect has been said to confirm the Pollyanna principle, where individuals tend "to use or accept positive words of feedback more frequently than negative words of feedback".
The effect is consistently found when the assessment statements are vague. People are able to read their own meaning into the statements they receive, and thus the statement becomes "personal" to them. The most effective statements include the phrase "at times", such as "At times you feel very sure of yourself, while at other times you are not as confident." This phrase can apply to almost anyone, and thus each person can read a "personal" meaning into it. Keeping statements vague in this manner ensures observing the Forer effect in replication studies.
Individuals are more likely to accept negative assessments of themselves if they perceive the persons presenting the assessments as high-status professionals. Evidence also suggests that people with authoritarian or neurotic personalities or who have a greater than usual need for approval are more likely to manifest the Barnum effect.
- The subject believes that the analysis is personalized, and thus applies personal meaning to the statements. "It is regrettable that academic psychology has not paid more attention to the cold reading technique", Denis Dutton wrote in 1988, "in as much as the widespread practice of successful cold reading forms the basis for much of the belief in paranormal powers to be found in society today." While academic psychologists had focused in their studies on students, Dutton called for "analysis of the actual techniques and methods used by proficient cold readers".