The Dutch military is trying out a new secret weapon: introverts

We have a tendency to glorify extroversion as a necessary trait in our leaders—but that’s now changing.

Officer Mike Erwin’s opinion about the military’s extrovert ideal shifted during his tours of duty in Iraq and Afghanistan. “I started noticing a trend,” he tells Quartz. “Many of these great leaders were fiercely quiet. They were men of few words and very good at planning and very deliberate when they spoke with great intent and great conviction. And everybody would listen.”

After his third deployment, Erwin studied personality psychology at the University of Michigan, focusing his master’s thesis on the character strengths of leadership. He then taught at West Point, where he met Susan Cain, author of Quiet, who spoke about the power of introversion in a popular TED talk.

“I invited her to speak to my cadets, and they were spellbound,” he says, adding that the many introverts in the room immediately “realized that they could lead too.” Erwin names US general Charles Krulak as a notable introverted military leader.

“Introverts score higher in the character strengths of prudence and perspective,” Erwin tells Quartz. “And these are strengths critical to the military skill set of planning.”

After Erwin completed his tour of active duty this year, he joined Cain’s Quiet Leadership Institute (QLI) as CEO, where he’s working with companies like Proctor & Gamble and institutions like NASA to evangelize the message that introverts make good leaders.

One of his clients is the Royal Netherlands Air Force, whose culture “places a high value on being loud, clear and visible,” he says. “This emphasis drives their organizational culture.”

He is taking the academy through a course that teaches the differences between introversion and extroversion, including the neurobiological differences between extroverts and introverts; how office design affects productivity for different personality types; how to run meetings in a way that surfaces the best ideas (research shows that usually three people do 70 % of the talking); and Free Trait Theory (the idea of acting out of character for a short period of time for a specific objective).

Colonel Elanor O’Sullivan, director of innovation for the Royal Netherlands Air Force, tells Quartz: “What we found is that our selection system, almost by default, has a preference for more extroverted people than more introverted people. It’s not written in our documents; it’s unconscious.” She estimates that around 85% of the leaders within the Royal Netherlands Air Force are extroverted, and she’s leading an initiative to change that among the 50,000 military personnel that make up the Dutch Armed Forces. This year, they have promoted more introverted leaders, and are looking at using different personality assessment tests to screen candidates when recruiting.

Ever since the Netherlands has implemented changes, several other militaries around the world, including Australia, Finland, Germany, and the UK, have inquired about results. “They want to know that there is no change in the quality of the operations; that at least as many people are coming home safe,” says O’Sullivan, adding that it will take a while to measure the effects of the changes. Cain has also received inquiries from hundreds of military personnel from around the world.

Shifting too far to the other end of the spectrum in what we prize in leaders is also a risk. Erwin says: “It’s not to create an introvert ideal, where introverts suddenly become the ideal commodity.” But championing leaders with more diverse styles is a good start.