Skeptic's Dictionary: Forer effect

"The Forer effect refers to the tendency of people to rate sets of statements as highly accurate for them personally even though the statements could apply to many people.

Psychologist Bertram R. Forer found that people tend to accept vague and general personality descriptions as uniquely applicable to themselves without realizing that the same description could be applied to just about anyone. Consider the following as if it were given to you as an evaluation of your personality.

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.

Forer gave a personality test to his students, ignored their answers, and gave each student the above evaluation. He asked them to evaluate the evaluation from 0 to 5, with "5" meaning the recipient felt the evaluation was an "excellent" assessment and "4" meaning the assessment was "good." The class average evaluation was 4.26. That was in 1948. The test has been repeated hundreds of time with psychology students and the average is still around 4.2 out of 5, or 84% accurate.

In short, Forer convinced people he could successfully read their character. His accuracy amazed his subjects, though his personality analysis was taken from a newsstand astrology column and was presented to people without regard to their sun sign. The Forer effect seems to explain, in part at least, why so many people think that pseudosciences "work". Astrology, astrotherapy, biorhythms, cartomancy, chiromancy, the enneagram, fortune telling, graphology, rumpology, etc., seem to work because they seem to provide accurate personality analyses. Scientific studies of these pseudosciences demonstrate that they are not valid personality assessment tools, yet each has many satisfied customers who are convinced they are accurate."