The Forer (Barnum) Effect

I am sure that most of you have seen those posts which claim to tell you your personality by the way you sleep, by the way you eat Oreos, by the date you were born (astrology & horoscopes), by what your favorite color is, etc. You may be surprised at how many people actually believe in these personality “tests” (maybe you do, too?). The Oreos one is my favorite because it is beyond stupid. If you haven’t seen it, here is one of the many sites which feature the “quiz.” I especially find the “psychologists have discovered” part distasteful, as people generally believe everything claimed to have been discovered by scientists. Here is one of the many versions out there:

So, if all these “tests” are bogus, then why do people believe in them? Why would anyone be convinced that they work if they, in fact, do not? The answer is simple: the Forer Effect (sometimes called the Barnum Effect).

Basically, the Forer (or Barnum) Effect is the tendency of people to rate statements about their personality as highly accurate, even though these same statements could apply to almost everyone else.

In 1949, Bertram R. Forer published a study in the Journal of Abnormal and Social Psychology where he describes how the phenomena works. In the study, Forer had 39 of his students take a personality evaluation task (which he himself made) called Diagnostic Interest Bank. One week later, he gave his students their “personality sketch” and instructed them to refrain from showing it to each other.

“It was essential,” Forer wrote, “that no student see the sketch received by any other student because all sketches were identical.” All the sketches had the following statements:

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 orvdone 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 reveling 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

Starting to sound a bit like you? That’s because these statements generally apply to every single one of us at one point or another in life. And, in fact, Forer’s students rated the personality sketch to be highly accurate at representing their personalities. These are the results obtained from the study:

As you can see, when asked to rate the accuracy of the personality sketch (0 being poor and 5 being perfect), most students rated the sketch as a 4 and a 5, even though they all received the same personality sketch. (N represents the number of students in the study).

Here’s a demonstration Derren Brown did on his program, Trick of the Mind, where he basically replicated Forer’s study on three distinct groups of people. One group from the UK, another from the U.S., and a third from Spain. Check it out: