Forer effect
The Forer effect is the tendency that people have to find general statements about themselves to be very accurate. It was discovered and is named after Bertram R. Forer in 1948 after Forer gave his students a personality test, then gave them back an evaluation containing extremely general statements. The text Forer used is as follows:
You have a need for other people to like and admire you, and yet you tend to be critical of yourself. While you have some personality weaknesses you are generally able to compensate for them. You have considerable unused capacity that you have not turned to your advantage. Disciplined and self-controlled on the outside, you tend to be worrisome and insecure on the 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 also pride yourself as an independent thinker; and do not accept others' statements without satisfactory proof. But you have found it unwise to be too frank in revealing yourself to others. At times you are extroverted, affable, and sociable, while at other times you are introverted, wary, and reserved. Some of your aspirations tend to be rather unrealistic.
Having given this to his students, he asked them to rate from zero to five how accurate he felt this analysis was. The average given by the class was 4.26. The test has been repeated on many students since, and the average is always similarly high.