Taking Psychology with You

How to Avoid the “Barnum Effect”

How well does the following paragraph describe you?

Some of your aspirations tend to be pretty unrealistic. At times you are extroverted, affable, and sociable, while at other times you are introverted, wary, and reserved. You pride yourself on being an independent thinker and do not accept others' opinions without satisfactory proof. You prefer a certain amount of change and variety, and you become dissatisfied when hemmed in by restrictions and limitations. At times you have serious doubts as to whether you have made the right decision or done the right thing.

When people believe that this description was written just for them, as the result of a personalized horoscope or handwriting analysis, they all say the same thing: “It describes me exactly!” Everyone thinks this description is accurate because it is vague enough to apply to almost everyone and it is flattering. Don't we all consider ourselves to be “independent thinkers”?

This is why many psychologists worry about the “Barnum effect” (Snyder & Shenkel, 1975). P. T. Barnum was the great circus showman who said, “There's a sucker born every minute.” He knew that the formula for success was to “have a little something for everybody,” which is just what unscientific personality profiles, horoscopes, and handwriting analysis (graphology) have in common. They have “a little something for everyone” and are therefore nonfalsifiable.

For example, graphologists claim that they can identify your personality traits from the form and distribution of your handwritten letters. Wide spacing between words means you feel isolated and lonely. If your lines drift upward, you are an “uplifting” optimist, and if your lines droop downward, you are a pessimist who feels you are being “dragged down.” If you make large capital I's, you have a large ego.

Graphologists are not the same as handwriting experts, who are trained to determine, say, whether a document is a forgery. Graphologists, like astrologers, usually know little or nothing about the scientific method, how to correct for their biases, or how to empirically test their claims. That is why the many different graphological approaches usually conflict. According to one system, a certain way of crossing t's reveals someone who is vicious and sadistic; according to another, it reveals a practical joker (Beyerstein, 1996).

Whenever graphology has been tested empirically, it has failed. A meta-analysis of 200 published studies found no validity or reliability to graphology in predicting work performance, aptitudes, or personality. No school of graphology fared better than any other, and no graphologist was able to perform better than untrained amateurs making guesses from the same writing samples (Dean, 1992; Klimoski, 1992).

If graphology were just an amusing game, no one would worry about it, but unfortunately it can have harmful consequences. Graphologists have been hired by companies to predict a person's leadership ability, attention to detail, willingness to be a good team player, and more. They pass judgment on people's honesty, generosity, and even supposed criminal tendencies (Tang, 2012). How would you feel if you were turned down for a job because some graphologist branded you a potential thief on the basis of your alleged “desire-for-possession hooks” on your S's?

If you do not want to be a victim of the Barnum effect, research offers this advice to help you think critically about graphology and its many cousins:

Beware of all-purpose descriptions that could apply to anyone. Sometimes you doubt your decisions; who among us has not? Sometimes you feel outgoing and sometimes shy; who does not? Do you “have sexual secrets that you are afraid of confessing”? Just about everybody does.
Beware of your own selective perceptions. Most of us are so impressed when an astrologer, psychic, or graphologist gets something right that we overlook all the descriptions that are plain wrong. Be aware of the confirmation bias—the tendency to explain away all the descriptions that don't fit.
Resist flattery and emotional reasoning. This is a hard one! It is easy to reject a profile that describes you as selfish or stupid. Watch out for the ones that make you feel good by telling you how wonderful and smart you are, what a great leader you will be, or how modest you are about your exceptional abilities.

If you keep your ability to think critically with you, you won't end up paying hard cash for soft answers or taking a job you dislike because it fits your “personality type.” In other words, you'll have proved Barnum wrong.