For Andrew Jetter, it was a matter of eye contact. Inclined to be an introvert, the bank president had to force himself to look others in the eyes.

“Making small talk … I had to practise that,” said the chief executive of the Federal Home Loan Bank of Topeka, Kansas.

“I have to force myself to greet new people. The hardest thing is to go to a big conference where there are 150 there and I know three or four, maybe. It’s a challenge.”

Jetter worked hard and made it to the top of his profession without having the natural gregariousness – or what psychologists call extraversion – usually associated with leadership.

It’s a journey taken by many shy or introverted people, who represent anywhere from 25 per cent to 40 per cent of the population.

But a new academic study shoots holes in the theory that you have to be an extravert to be a good leader. It turns out that introverts, or shy people, can be great leaders, too.

A recently-published analysis by Adam Grant, an associate professor of management at the University of Pennsylvania’s Wharton School, looked at 73 previous studies that found extraversion was “the most consistent predictor of leadership emergence”.

But Grant wrote: “In contrast to popular wisdom, our work suggests that extraversion can be a liability for leaders.”

Stripped to its most basic, Grant’s research concluded that extraverted leaders – who may be big talkers comfortable with sharing opinions and, often, orders – are very good with subordinates who tend to be more passive or comfortable with being told what to do.

But in organisations where subordinates are more dynamic or aggressive, extraverted leaders may clash or fail to listen to the input that they should from others.

In workplaces with confident, self-starting workers, introverted leaders shine. They listen better, and they’re more receptive to good ideas from their subordinates, Grant found.

At Kansas Action for Children, a non-profit advocacy organisation, Chief Executive Shannon Cotsoradis had doubted she could fill the shoes of her predecessor, a dynamic extravert.

“I’ve always perceived myself as an introvert and saw it as a leadership handicap,” Cotsoradis said.

“I really wondered if I could be successful in a CEO role. I wasn’t sure it played to my strengths.”

Like Jetter, Cotsoradis sought guidance from a counsellor. Through Right Management, Jetter connected with Mack Harnden, and Cotsoradis worked with Connie Russell, both of whom provided leadership coaching.

“What was pivotal for me was changing the way I thought a leader should be,” Cotsoradis said.

“I learned to trust my own leadership brand. I’ve found ways to make the demands of the job work for me.”

When she counsels introverts, Russell said, she finds that their challenge typically is to become comfortable sharing enough of themselves to make interpersonal connections, the foundation for building trust among subordinates.

“Without connections, people assume you’re self-centred or too self-effacing to take command,” Russell said.

“You have to make connections to show you have the self-confidence to command respect.”

Harnden said he encouraged introverts to “toot their own horns a little bit, or they’ll be bypassed”.

They have to find a balance point, he said, between humility and resolve.

As Grant’s study found, the introverted leader sometimes has an advantage over extraverted leaders when it’s important to share the spotlight with others.

“That’s one of the best ways to build support as well as bench strength – sharing the glory,” Harnden said.