Fortune-tellers know how to make good use of the Forer effect to amaze people with their 'accurate predictions.' fergregory/iStock/Thinkstock

Have you noticed that you're the kind of person who, while inherently empathetic, is also marked by a strong streak of independent thinking? 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 Forer effect -- also referred to as the Barnum effect, after famous 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 everyone was gullible enough to consider the terms unique to them.



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 cousin. 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 description was spot-on or close to it. A few examples from the sketch are phrases like, "You have a great need for other people to like and admire you," "You have found it unwise to be too frank in revealing yourself to others" and "You have a tendency to be critical of yourself" [source: Foer]. (And note that this experiment is still conducted in present-day "intro to psychology" classes. So beware.)

Can you make a guess about what industry might find the Forer effect particularly helpful? If you said astrology, you're probably a really intuitive person. But consider that marketing and advertising is 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 -- 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.