In 1948, during an introductory course in psychology, psychologist Bertram R. Forer asked his students to complete a personality test. He then informed them that in the next course, after analyzing the tests, he would provide everyone with a personalized description of their personality.
When submitting the test results, he first asked each student to keep his or her personal description to himself or herself and then to rate on a scale from 0 (does not correspond at all) to 5 (corresponds perfectly) how well the description fits with who they are. What the students did not know yet was that they had all received exactly the same descriptive text.
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.
Your sexual adjustment has presented problems for you.
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.
The results clearly show that the students have been trapped. Only one student reported a score below 4 and the average was 4.31! Forer had just demonstrated the existence of a cognitive bias: the Barnum effect (also called the Forer effect).
For this effect to work, it is important to consider several factors. The descriptive text must first be sufficiently vague. Indeed, formulas such as “At times you are extroverted, affable, sociable, while at other times you are introverted, wary, reserved.” are general enough that the vast majority of people can identify with them and find resonance in their personal lives. The description must also contain more positive assessments than negative ones. Studies have shown that the effect is greater when individuals actually believe that each feedback is unique. Finally, it is important that individuals trust in the person who gives them feedback and that they attribute some form of authority to them.
Does this ring a bell? So think about it next time you read the horoscope, go see a psychic, use graphology, numerology or listen to a political speech.
Bibliography
Forer, B. R. (1949). The fallacy of personal validation : A classroom demonstration of gullibility. The Journal of Abnormal and Social Psychology, 44(1), 118‑123. https://doi.org/10.1037/h0059240
Vocabulary
To rate : noter, évaluer.
To fit with : correspondre.
Sexual adjustment : the process of establishing a satisfactory relationship with one or more sexual partners (APA Dictionary of Psychology).
To get hemmed in : se faire enfermer.
To pride yourself : être fier de vous.
Unwise : peu judicieux.
To be trapped : être piégé.
It rings a bell : ça me dit quelque chose.
A psychic : un médium, un voyant.