The Barnum effect, also called the Forer effect, is a common psychological phenomenon whereby individuals will give high accuracy ratings to descriptions of their personality that supposedly are tailored specifically to them but that are, in fact, vague and general enough to apply to a wide 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, graphology, aura reading, and some types of personality tests.
The Forer effect is a specific example of the so-called "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. Subjective validation occurs when two unrelated or even random events are perceived to be related because a belief, expectation, or hypothesis demands a relationship. For example, while reading a horoscope, people actively seek a correspondence between its contents and their perception of their personality.
The name "Barnum effect" seems to have originated with psychologist Paul Meehl in reference to the American circus entertainer P. T. Barnum, who is said to have stated that "we have something for everybody."
The Forer effect is manifested in response to statements that are called "Barnum statements", meaning characterizations made about an interlocutor that the interlocutor finds valid even though the statements are generalizations that could apply to almost anyone. Such statements are used by fortune tellers, astrologers, and other practitioners of chicanery to convince customers that they, the practitioners, are in fact endowed with a paranormal gift.
In 1947, a psychologist named 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 of him or her 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 Bertram R. Forer gave a psychology test--his so-called "Diagnostic Interest Blank"--to 39 of his psychology students who were told that they would each receive a brief personality vignette or sketch based on their test results. One week later Forer gave each student a purportedly individualized sketch and asked each of them to rate it on how well it applied. In reality, each student received the same sketch, consisting of the following items:
- You have a great need for other people to like and admire you.
- You have a tendency to be critical of yourself.
- You have a great deal of unused capacity which you have not turned to your advantage.
- While you have some personality weaknesses, you are generally able to compensate for them.
- Disciplined and self-controlled outside, you tend to be worrisome and insecure inside.
- At times you have serious doubts as to whether you have made the right decision or done the right thing.
- You prefer a certain amount of change and variety and become dissatisfied when hemmed in by restrictions and limitations.
- You pride yourself as an independent thinker and do not accept others' statements without satisfactory proof.
- You have found it unwise to be too frank in revealing yourself to others.
- At times you are extroverted, affable, sociable, while at other times you are introverted, wary, reserved.
- Some of your aspirations tend to be pretty unrealistic.
- Security is one of your major goals in life.
On average, the students rated its accuracy as 4.26 on a scale of 0 (very poor) to 5 (excellent). Only after the ratings were turned in was it revealed that each student had received an identical sketch assembled by Forer from a newsstand astrology book. The sketch contains statements that are vague and general enough to apply to most people.
In another study examining the Forer effect, students took the MMPI personality assessment and researchers evaluated their responses. The researchers wrote accurate evaluations of the students' personalities but gave the students an accurate assessment and a fake assessment using vague generalities. Students were then asked to choose which personality assessment they believe was their own, actual assessment. More than half of the students (59%) chose the fake assessment as opposed to the real one.
The Forer effect is also known as the "Barnum effect". This term was coined in 1956 by American psychologist Paul Meehl in his essay "Wanted -- A Good Cookbook". He relates the vague personality descriptions used in certain "pseudo-successful" psychological tests to those given by showman P. T. Barnum.
Forer attributed the Barnum effect to gullibility. The effect has been said to confirm the so-called "Pollyanna principle", which states that individuals tend "to use or accept positive words or feedback more frequently than negative words of feedback".
Two factors are important in producing the Forer effect, according to the findings of replication studies. The content of the description offered is important, with specific emphasis on the ratio of positive to negative trait assessments. The other important factor is that the subject trusts the honesty of the person providing 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.
In 2011, the study was repeated with the statements altered so that they applied to organizations rather than individuals. The results were similar, suggesting that people anthropomorphize organizations and are gullible when interpreting their characters.
Studies show that people are more likely to believe in astrology if they are presented with personal horoscopes that depicts them in a positive light.
Also, individuals are more likely to accept negative assessments of themselves if they perceive the persons presenting them with those assessments as high-status professionals.
Some evidence 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.
Studies suggest that the Forer effect is universal--it has been observed in people from many cultures and locations. In 2009, psychologists Paul Rogers and Janice Soule conducted a study that compared the tendencies of Westerners to accept Barnum personality profiles to the tendencies of Chinese people. They were unable to find any significant differences.
Later studies have found that subjects give higher accuracy ratings if the following are true:
The method in which the Barnum personality profiles are presented can affect the extent to which people accept them as their own. For instance, Barnum profiles that are more personalized--perhaps containing a specific person's name--are more likely to yield higher acceptability ratings than those that could be applied to anyone.
Subjects who, for example, believe in the accuracy of horoscopes have a greater tendency to believe that the vague generalities of the response apply specifically to them. Studies on the relationship between schizotypy and susceptibility to the Forer effect have shown high amounts of correlation. However, Rogers and Soule's 2009 study (see "Variables influencing the effect" above) also tested subjects' astrological beliefs. Both the Chinese and Western skeptics were more likely to identify the ambiguity in the Barnum profiles. This suggests that individuals who do not believe in astrology are possibly influenced less by the effect.
Self-serving bias has been shown to cancel the Forer effect. According to the self-serving bias, subjects accept positive attributes about themselves while rejecting negative ones. In one study, subjects were given one of three personality reports. One contained Barnum profiles including socially desirable personality traits, one contained profiles full of negative traits (also called "common faults"), and the last contained a mixture of the two.
Subjects who received the socially desirable and mixed reports were far more likely to agree with the personality assessments than the subjects who received negative reports, though it should be noted that there was not a significant difference between the first two groups.
In another study, subjects were given a list of traits instead of the usual "fake" personality assessment. The subjects were asked to rate how much they felt these traits applied to them. In line with the self-serving bias, the majority of subjects agreed with positive traits about themselves and disagreed with negative ones. The study concluded that the self-serving bias is powerful enough to cancel out the usual Forer effect.
In a 1971 experiment by Bernie I. Silverman, subjects were presented with twelve personality sketches drawn from a set of horoscopes and asked to choose the four that best described them. When the descriptions were not identified by astrological sign, subjects were not particularly likely to pick the horoscope for their own sign. When the descriptions were labeled by sign, however, subjects were more likely to pick the horoscope for their own sign.
C. R. Snyder and R. J. Shenkel carried out a study in which they asked their students to prepare uniform Barnum descriptions for a group of subjects; these descriptions were then presented to study participants under the guise of being individualized horoscopes. Subjects in one group were not asked for personal information; those in a second group were asked to provided their month of birth; those in a third group were asked for the exact date of their birth. Those in the third group were most likely to say that their "horoscopes" applied to them; those in the first group were least likely to do so.
In 1977, Ray Hyman wrote about the way in which palm readers and other such hucksters exploit the Forer effect to take advantage of victims (or 'marks'). He provided a list of factors that help these tricksters to dupe their prey. For example, hucksters are more likely to be successful if they exude an air of confidence ("If you look and act as if you believe in what you are doing, you will be able to sell even a bad reading to most of your subjects"), if they "[m]ake creative use of the latest statistical abstracts, polls, and surveys" showing "what various subclasses of our society believe, do, want, worry about, and so on", if they employ "a gimmick, such as a crystal ball, tarot cards, or palm reading", if they are alert to the clues provided about their clients by such details as their "clothing, jewelry, mannerisms and speech", if they are not afraid of "hamming it up", and if they use flattery.
Michael Birnbaum, a Professor of Psychology at California State University, Fullerton, has noted that the Forer effect is used by magicians and psychics when they give so-called "cold readings", as well as by certain TV personalities who claim psychoanalytical expertise and profess to be able to diagnose a guest's psychological problems in a few minutes. "Real psychologists are horrified by this practice", states Birnbaum, but they fail to criticize it vigorously enough in public, and so it continues to be treated with a respect it doesn't deserve. "It is regrettable that academic psychology has not paid more attention to the cold reading technique," Denis Dutton wrote in 1988, "inasmuch 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".
A 2016 article explained to marketers how to use the Forer effect to win customers. The main piece of advice was to employ flattery.
"The moral of the Barnum Demonstration", Birnbaum has said, is that "Self-validation is no validation. Do not be fooled by a psychic, quack psychotherapist, or a phony faith healer who uses this trick on you! Be skeptical and ask for proof. Keep your money in your wallet, your wallet in your pocket, and your hand on your wallet."