Forer's demonstration[edit]
In 1948, in what has been described as a "classic experiment",[7] 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:[8]
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.[8] 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.[9]
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.[10][11]
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".[6]
https://en.wikipedia.org/wiki/Barnum_effect