Barnum Effect 

The Barnum effect is manifested in response to statements that are called "Barnum statements", meaning general characterisations attributed to an individual are perceived to be true of them, even though the statements are such generalizations, they could apply to almost anyone. Such techniques are used by fortune tellers, astrologers, and other practitioners to convince paying customers that they, the practitioners, are in fact endowed with a paranormal gift.^[5] The 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."^[6] A related and more general phenomenon is that of subjective validation.^[7] 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.

Early research[edit]

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, graphologicalanalyses, 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.^[8][9]

In 1948, in what has been described as a "classic experiment",^[10] 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:^[11]

1. You have a great need for other people to like and admire you.
2. You have a tendency to be critical of yourself.
3. You have a great deal of unused capacity which you have not turned to your advantage.
4. While you have some personality weaknesses, you are generally able to compensate for them.
5. Your sexual adjustment has presented problems for you.
6. Disciplined and self-controlled outside, you tend to be worrisome and insecure inside.
7. At times you have serious doubts as to whether you have made the right decision or done the right thing.
8. You prefer a certain amount of change and variety and become dissatisfied when hemmed in by restrictions and limitations.
9. You pride yourself as an independent thinker and do not accept others' statements without satisfactory proof.
10. You have found it unwise to be too frank in revealing yourself to others.
11. At times you are extroverted, affable, sociable, while at other times you are introverted, wary, reserved.
12. Some of your aspirations tend to be pretty unrealistic.
13. Security is one of your major goals in life.

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 was it revealed that each student had received an identical sketch assembled by Forer from a newsstand astrology book.^[11] The sketch contains statements that are vague and general enough to apply to most people.

Forer attributed the effect to gullibility.^[12] The effect has been said to confirm the so-called "Pollyanna principle", which states that individuals tend "to use or accept positive words of feedback more frequently than negative words of feedback."^[8]