Have you been conned by the Greatest Showman
What is the Barnum–Forer effect and how not to fall fowl of it.
If you know the movie, The Greatest Showman, you will learn the basics of the life of PT Barnum. He was born in 1810 in Bethel, Connecticut, and became a successful promoter after moving to New York City. His great showman title comes less from the Barnum American Museum in NYC but from the center ring of what became known as the Ringling Bros. and Barnum & Bailey Circus. You may not know that they named a cognitive bias after him. Like his circus, he shared the naming with Bertram Forer, and the bias is known as the Barnum–Forer effect.
The Barnum–Forer effect
The power of this effect, or bias, is the need many of us have to receive information that reinforces what we know or want to believe. You see the effect in action when you read your horoscope, attend a 'reading,' or interact with a fortune teller. The latter is very good at giving 'cold readings' of the person in front of them. Yet, as we will see, there are much more subtle ways we all come under this bias’s effect.
Technically, the Barnum–Forer effect is a phenomenon where we tend to give believability to descriptions of ourselves that are supposedly explicitly tailored to us yet are, in fact, vague and general enough to apply to a wide range of people. The effect is manifested in response to "Barnum statements," meaning that broad characterizations attributed to an individual are perceived to be true for them, even though the ideas are so generalized that they could apply to almost anyone.
Here are a few Barnum Statements for you:
You tend to be critical of yourself.
You have a great deal of unused capacity that you have yet to turn to your advantage.
While you have some personality weaknesses, you can generally compensate for them.
Sometimes you need clarification about whether you have made the right decision or done the right thing.
You pride yourself as an independent thinker and only accept others' statements with satisfactory proof.
Few of us disagree about these things about ourselves, but of course, they appear specific to us but apply to everyone. This is mostly harmless, but knowing it is possible may change how you think about things.
Limiting the effects.
"The moral of the Barnum demonstration," said Michael Birnbaum, a professor of psychology at California State University, Fullerton, “is that self-validation is no validation. Do not be fooled by a psychic, quack psychotherapist, or phony faith healer who uses this trick on you! Be skeptical and ask for proof. Keep your money in your wallet, your wallet in your pocket, and your hand on your wallet."
So, what can you do to protect yourself from the effect:
Watch for Fortune Cookie knowledge - fortune cookies are written en-masse, and horoscopes, by definition, must cover 1/12 of the population on any given day. They can’t be talking to you except by luck.
Check for data - comments that are specific need evidence of validity. While the personality test you did in a back edition of a Cosmo makes sense, these are usually too brief to do any good and typically have no scientific basis.
Be skeptical and read between the lines - unless you can honestly say that it wouldn't fit anyone besides you, chances are it has a touch of the Barnum effect.
Beware of secondhand 'professionals' - few of us understand very complex ideas, so we tend to substitute those we trust for our own. Your friend advises you what professionals think may have many biases working for or against them.
Past and the future
Not only is that past performance no guarantee of future results, but it’s also a terrible way to live your life. The challenge of the Barnum effect is that it seems powerful because it reinforces what you already believe about yourself.
We get to decide what future we want to live in; anything else is just a story you are telling yourself.