What Personality Tests Tell Us About Ourselves The desire to find our tribe is universal. We like to know who we are and where we belong. This fascination has led to a thriving industry built on the marketing and sale of personality tests. These tests offer individuals – and, increasingly, employers – quick and easy insights that can be used to make some of life's biggest decisions. But most fail to stand up to scientific scrutiny. This week, we revisit our 2017 episode about the world of personality testing, and explore the many different ways we assess personality and potential – from the Chinese zodiac to Harry Potter houses to the Myers-Briggs test.

What Can A Personality Test Tell Us About Who We Are?

The Sorting Hat

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Courtesy of Pottermore.com
Images of the seals that represent each of the Hogwarts houses.
Courtesy of Pottermore.com

In one of the most famous scenes from the Harry Potter series, a group of kids, new to the Hogwarts School of Witchcraft and Wizardry, line up before an old and crumpled wizard's hat. It is the sorting hat. The hat will tell them which house they'll belong to during their Hogwarts education.

There is something deeply appealing about the sorting hat. It is wise. It seems to know people better than they know themselves.

We humans love this kind of insight. And our drive to better understand ourselves and the people around us has led to the creation of a multi-billion dollar industry built around personality testing.

Probably the most famous of all personality tests is the Myers-Briggs Type Indicator, or MBTI. But there are plenty of others, too. These tests categorize people based on personality traits. Are you an introvert or an extrovert? Someone who likes unexpected challenges, or someone who prefers structure and calm? Many of America's most successful companies use personality tests to gain a better understanding of their workers. Many individuals use them to gain a better understanding of themselves.

One Hidden Brain listener, Ally Adler, took the Myers-Briggs test when she was 26 and miserable in her job.

"It really helped me understand myself in a way that I hadn't before so I could work around and manage challenges both in my personal and professional life," she says.

At the Potterverse convention in Baltimore, adults and children alike enjoy talking about their Harry Potter Hogwarts "houses" — and the houses they think their friends should be in. Tara Boyle/NPR hide caption

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Tara Boyle/NPR

At the Potterverse convention in Baltimore, adults and children alike enjoy talking about their Harry Potter Hogwarts "houses" — and the houses they think their friends should be in.

Tara Boyle/NPR

But other people say tests like these are deeply flawed. Listener Matthew Gale says the Myers-Briggs got him completely wrong.

"My experience with Myers-Briggs played no small part in ruining me emotionally for years," he says.

While the effectiveness of these tests can be endlessly debated, one thing is clear. With a few exceptions, most do not stand up to scientific scrutiny. They typically aren't peer reviewed and usually fail basic standards of validity and reliability. Adam Grant, a psychology and management professor at the University of Pennsylvania, has written of his concerns with the Myers-Briggs, particularly when companies use the results to guide hiring and firing decisions.

"It's a great way to weed out diversity," Grant says.

Allen Hammer, the former chair of the Myers & Briggs Foundation, disagrees. He believes the Myers-Briggs is as reliable as other personality tests. And he says Grant is wrong when it comes to evidence that the Myers-Briggs cannot predict real world outcomes; for example, he says, "when people matched roommates on their psychological type they got a 65 percent decrease in request for roommate changes."

This week, we delve into the world of personality tests, and discover new research that suggests the power of personality assessments may not be in pinpointing the person you are, but the person you have the potential to become.

Additional Resources:

"Can Superstition Create a Self-Fulfilling Prophecy? School Outcomes of Dragon Children of China," by Naci H. Mocan and Han Yu, 2017.

Hidden Brain is hosted by Shankar Vedantam and produced by Jennifer Schmidt, Parth Shah, Rhaina Cohen, Laura Kwerel, and Thomas Lu. Our supervising producer is Tara Boyle. You can also follow us on Twitter @hiddenbrain, and listen for Hidden Brain stories each week on your local public radio station.

Editor's note: In the original version of this story, interviewee Adam Grant mixed up the definitions of scientific reliability and validity. This error has been corrected in this version of the story.

According to the American Psychological Association, validity is defined as "the degree to which empirical evidence and theoretical rationales support the adequacy and appropriateness of conclusions drawn from some form of assessment." The APA defines reliability as "the trustworthiness or consistency of a measure, that is, the degree to which a test or other measurement instrument is free of random error, yielding the same results across multiple applications to the same sample."