When personality surveys tap into one of your cognitive biases

Reading time: 4 minutes

Personality surveys flourish on the internet every month, and it’s now virtually impossible to get an interview without taking a personality questionnaire. As with everything, it’s important to keep a critical eye, because some of these flourishing questionnaires are personality questionnaires in name only. These so-called questionnaires will blithely rely on one of your cognitive biases to get you to agree with their results. This cognitive bias is called the Barnum effect.

WHAT IS THE BARNUM EFFECT?

The Barnum effect is a cognitive bias inducing anyone to accept a vague description of personality as applying specifically to themselves.

This psychological phenomenon takes its name from circus performer Phineas Taylor Barnum, renowned for his manipulative skills (he created Freak Shows and is featured in the film The Greatest Showman). Legend has it that during his shows, he would pick out someone in the audience and tell you all about them just by looking at them. His secret was that he never announced anything very specific to one person, but rather vague descriptions that could apply to literally anyone!

THE ORIGIN OF THE BARNUM EFFECT

This cognitive bias first came to prominence in 1949, when psychology professor Bertram Forer decided to administer a personality questionnaire to each of his students. Afterwards, Forer threw his students’ results in the garbage can and copied a personality analysis from the astrological section of some magazine. A few days later, he announces to his students that he’s going to give them each their results from the personality questionnaire. He gives each student the following text:

You need to be loved and admired, yet you’re critical of yourself. You may have weaknesses in your personality, but you usually know how to compensate for them. You have considerable potential that you haven’t turned to your advantage. On the outside, you’re disciplined and self-controlled, but on the inside, you tend to be preoccupied and unsure of yourself. Sometimes you seriously question whether you’ve made the right decision or done the right thing. You prefer a certain amount of change and variety, and become dissatisfied if you’re surrounded by restrictions and limitations. You pride yourself on being an independent spirit, and will only accept the opinion of others when duly demonstrated. You think it’s clumsy to reveal yourself too easily to others. At times, you’re outgoing, talkative and sociable, while at other times you’re introverted, circumspect and reserved. Some of your aspirations tend to be rather unrealistic.

The students were unaware that Forer had given the same report to all his students.

Forer then asks them to rate how well their results match their personality, between 0 and 5. The average score was 4.2 out of 5, indicating a high level of agreement between the students and the text they had been given. Forer thus demonstrated experimentally for the first time the existence of the “Barnum effect”.

HOW DOES THIS COGNITIVE BIAS WORK?

What is the Barnum effect based on to have such an impact and convince so many people? Why do so many people allow their minds to be manipulated by these tests? Quite simply, because they take advantage of our Achilles heel.

Psychologists Dickson and Kelly continued Forer’s research on this effect, and in particular found that the feeling of relevance of a result on a personality questionnaire increased according to 3 factors:

• persuading the subject that the analysis applied to him alone
• the subject’s recognition of the evaluator’s authority
• the presence of predominantly positive traits in the analysis

With these three factors, most people are convinced.

The descriptions resulting from these three factors are generally sufficiently general for your brain to be able to interpret them in a way that coincides with the way you perceive yourself.

For example: “You enjoy going out and spending time with your friends, but you also know how to enjoy a relaxing evening at home”. You’ll also find sentences containing words like: “sometimes“, “occasionally” or “you sometimes…”.

The Barnum effect can be found in a whole host of fields: certain personality questionnaires, clairvoyants, horoscopes, marketing, but also… political speeches (for example, Charles de Gaulle’s very typical “Je vous ai compris“).

THE BARNUM EFFECT, STAR OF MBTI

As I said in my introduction, the Barnum effect can be found in a large number of personality questionnaire results. You might think that this is especially true of questionnaires that can be found online for free. But that’s not all! We also find this effect in one of the best-known personality questionnaires: the MBTI! Here are just a few examples of the results you can get if you take the MBTI. Look out for the Barnum effect in these extracts:

INTJ-A / INTJ-T Architect Profile

Architects also like to share what they know, because they’re confident in their mastery of their chosen subjects, but they’d rather design and execute a brilliant plan in their field than share their opinions on “uninteresting” distractions like gossip.

The Consul personality ESFJ-A / ESFJ-T

Later in life, Consuls like to support their friends and loved ones.

The ESTP-A / ESTP-T Entrepreneur personality

As a result, school and other highly organized environments are problematic for Entrepreneurs. It’s certainly not because they’re not smart or able to do well, but because the regimented, sententious approach of formal education is so far removed from the hands-on learning that Entrepreneurs value.

The personality Director ESTJ-A / ESTJ-T

Their opinions are not just empty words.

The Barnum effect in all its glory: so-called “individualized” results from a 20-minute questionnaire, supposedly inspired by the theories of the great psychologist, and positive, empowering descriptions. When we read these results, we come away with a flattering view of ourselves. We’re happy and satisfied with the MBTI results.

HOW TO PROTECT YOURSELF AGAINST THE BARNUM EFFECT?

The magic formula is simple: a good dose of awareness, sprinkled with a touch of critical thinking. These are usually our best assets in everything. When you read your review of a personality questionnaire, ask yourself, “Can this description apply to other people around me?”