Oprah Winfrey’s Co-Author Arthur C. Brooks Explains How She Has ‘Cracked the Code’ for Handling Fame (Exclusive)

When Arthur C. Brooks and Oprah Winfrey worked on their new co-authored book, Build the Life You Want: The Art and Science of Getting Happier, they each took a personality test featured in one of the book’s chapters.

The test, called PANAS, is designed to measure how a person experiences emotions, both positive and negative, and its result sorts everyone who takes it into one of four types: the Mad Scientist, who experiences both positive and negative emotions strongly; the Cheerleader, whose positive emotions dominate; the Poet, who veers toward the negative; and the Judge, who reacts calmly to both positive and negative emotions.

Brooks, an academic and writer who spent several years as a CEO running a think tank, is a Mad Scientist type. “That means I am a happy person, but I’m also an unhappy person because you can be both,” he tells PEOPLE in this week’s issue.

Oprah is the exact opposite: a Judge, a person whose emotional balance keeps her from experiencing the highest highs or the lowest lows.

This, Brooks notes, may be one reason she’s been able to maintain a happy and authentic life — even while experiencing a level of fame that can destabilize others.

“I’ve known a lot of politicians and presidents, only because of the job that I had before. But since I wrote From Strength to Strength, I’ve known a lot of actors and athletes, because that was a book about strivers who struggle to move on with their lives. So I’ve met a lot of people really, really, really in the public eye. Most are not what they seem,” Brooks explains. “And the reason is because people struggle to maintain an image a lot because they need to. I’m super sympathetic to that.”

But Oprah is different, he adds.

“Oprah is literally what she seems, and the reason is because she has cracked the code on how to be a public person and to be privately content and happy at the same time,” he says. “I’ve rarely met anybody like that. Rarely have I met somebody like that… she’s at peace.”

It all comes from her personality as a Judge. “That means she doesn’t freak out about good or bad things,” he explains. “And the reason is because she’s a peaceful person. If she weren’t, she’d be out of her mind.”

“She’s probably one of the five most famous people in the world, and she would lose her mind, which famous people do,” Brooks adds.

Although many think they would love to be famous, Brooks cautions that it’s not as fun as it may appear.

“Fame is super hard on the brain,” he says. “And so people who get famous before they’re 15, for example, many never recover because the reward circuits are just blinkered forever.”

Build the Life You Want: The Art and Science of Getting Happier is available everywhere books are sold on Tuesday, Sept. 12.