Did That Astrologer Read You Right? That's the Barnum Effect

By: Kate Kershner  | 
crystal ball
Fortune tellers know how to make good use of the Barnum effect to amaze people with their predictions. fergregory/iStock/Thinkstock

Have you noticed that you're the kind of person who, while inherently empathetic, is also an independent thinker? Or perhaps you're more the type who is a little self-critical and insecure, but can defend yourself when needed? Maybe you're a human being, with various thoughts and feelings that sometimes contradict. Maybe you're that!

Welcome, my friends, to the Barnum effect, named after famous 19th-century showman P.T. Barnum, who was happy to manipulate people by drawing on their belief that he "understood" their personality in some implicit way. What was really happening? Simple: Barnum was giving a very broad description of "personality" and finding that many people were gullible enough to consider the terms unique to them. As he's famously quoted as saying, "There's a sucker born every minute."


The Power of Vague Personality Descriptions

The psychologist Bertram Forer first figured out that it was pretty darn easy for people to agree with vague descriptions about themselves without realizing they could apply to basically everyone and their cousins. That's why horoscope writers and palm readers can make people feel like vague personality descriptions apply specifically to them — while their responses feel like individual feedback, the responses are filled with information that applies to many people.


The Fallacy of Personal Validation: A Personality Test

Forer tested his hypothesis in a sneaky way: He gave a personality test to psychology students and then asked how well the results matched them. Only thing? They all got the exact same "sketch" of results that "described" their personality based on their unique answers. And pretty much everyone thought the personality feedback was spot-on or close to it. This classroom demonstration of gullibility is the Barnum effect, which is also called the Forer effect.

A few examples from the sketch are phrases like, "You have a great need for other people to like and admire you," "At times you have serious doubts as to whether you have made the right decision or done the right thing," "You have a great deal of unused capacity which you have not turned to your advantage," and "You have a tendency to be critical of yourself" [source: Forer]. This experiment is still conducted in some present-day "Intro to Psychology" classes. So beware. Your classmates may demonstrate this acceptance phenomenon.


Barnum Effect and Careers

Can you make a guess about what industry might find the Barnum effect particularly helpful? If you said astrology, you're probably a really intuitive person. The Barnum effect explains how a fortune teller can convince customers that general statements hold personal meaning. But consider that marketing and advertising are also quite dependent on people believing that they are the "kind of people" who would benefit from a product or have a "specific problem" for which they could purchase a solution.

Remember that it works best when you're hearing things about yourself that are positive statements — or at least understandable and sympathetic. Not everyone is going to agree that, say, at heart they're a "stubborn person who may pitch a fit when things go wrong," even though we all pretty much do that. But hearing that you find "change sometimes difficult to cope with" sounds a lot more relatable.


Lots More Information

Related Articles

  • Birnbaum, Michael H. "The Barnum Effect." California State University, Fullerton. (Jan. 19, 2015) http://psych.fullerton.edu/mbirnbaum/psych101/barnum_demo.htm
  • Carroll, Robert T. "Forer Effect." The Skeptic's Dictionary. Sept. 12, 2014. (Jan. 19, 2015) http://skepdic.com/forer.html
  • Forer, Bertram. "The Fallacy of Personal Validation." The Journal of Abnormal and Social Psychology. January 1949. (Jan. 19, 2015) http://apsychoserver.psych.arizona.edu/JJBAReprints/PSYC621/Forer_The%20fallacy%20of%20personal%20validation_1949.pdf