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What is Forer Effect?

What is forecast illusion?

What is Forer Effect? And how to expose a charlatan

Dear reader, it may surprise you, but I know you personally. This is how I would sum you up:

‘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 and sociable while at other times you are introverted, wary and reserved. Some of your aspirations tend to be pretty unrealistic. Security is one of your major goals in life.’

Do you recognise yourself?

On a scale from 1 (poor) to 5 (excellent), how was my assessment?

The Experiment

In 1948, psychologist Bertram Forer crafted this exact passage using astrology columns from various magazines. He then gave it to his students to read, suggesting that each person was getting a personalised assessment.

On average, the students rated their characterisations 4.3 out of five, i.e. they gave Forer an accuracy score of 86%. The experiment was repeated hundreds of times in the decades that followed, with virtually identical results.

Most likely you gave the text a 4 or 5, too. People tend to identify many of their own traits in such universal descriptions. Science labels this tendency the Forer effect (or the Barnum effect).

The Forer effect explains why the pseudo-sciences work so well – astrology, astrotherapy, the study of handwriting, biorhythm analysis, palmistry, tarot-card readings and séances with the dead. 

What’s behind the Forer effect?

First, the majority of statements in Forer’s passage are so general that they relate to everyone:

‘Sometimes you seriously doubt your actions.’

Who doesn’t?

Second, we tend to accept flattering statements that don’t apply to us:

‘You are proud of your independent thinking.’

Obviously! Who sees himself or herself as a mindless follower?

Third, the socal led feature positive effect plays a part: the text contains no negative statements; it states only what we are, even though the absence of characteristics is an equally important part of a person’s make-up.

Fourth, the father of all the fallacies, the confirmation bias: we accept whatever corresponds to our self image and unconsciously filter everything else out.

What remains is a coherent portrait.

Whatever tricks astrologers and palm readers can turn, consultants and analysts can too

‘The stock has significant growth potential, even in a very competitive environment. The company lacks the necessary impetus to fully realise and implement ideas from the development team. Management is made up of experienced industry professionals; however, hints of bureaucratisation are noticeable. A look at the profit and loss statement clearly shows that savings can be made. We advise the company to focus even more closely on emerging economies to secure future market share.’

Sounds about right, no?

In conclusion

How do you rate the quality of such a guru – for example, an astrologer? Pick twenty people and secretly assign each a number. Have him characterise the people and write his assessments down on cards. To ensure anonymity, participants never find out their numbers. Afterward, each receives a copy of all the cards. Only when the majority of people identify ‘their’ description is there real talent at hand. I am still waiting. 


Similar Biases:
Feature-Positive Effect – WHY CHECKLISTS DECEIVE YOU
Confirmation Bias (Part 1) – BEWARE THE ‘SPECIAL CASE’
Confirmation Bias (Part 2) – MURDER YOUR DARLINGS
Self-Serving Bias – DON’T BLAME ME


The above article is from the book The Art of Thinking Clearly by Rolf Dobelli. The article is only for educational and informative purposes to explain and understand cognitive biases. It is a great book, definitely worth a read!