Conventional wisdom tells us that leaders are the men and women who stand up, speak out, give orders, make plans and are generally the most dominant, outgoing people in a group. But that is not always the case, according to new research on leadership and group dynamics from Wharton management professor Adam Grant and two colleagues, who challenge the assumption that the most effective leaders are extroverts.

In fact, introverted leaders can be more effective than extroverts in certain circumstances. The determining factor is who leaders are managing, according to Grant and co-authors Francesca Gino of Harvard Business School and David Hofmann of the University of North Carolina’s Kenan-Flagler Business School.”

Extroverted leadership involves commanding the center of attention: being outgoing, assertive, bold, talkative and dominant. This offers the advantages of providing a clear authority structure and direction. However, pairing extroverted leaders with employees who take initiative and speak out can lead to friction, while pairing the same group of employees with an introverted leader can be a pathway to success, the researchers note.

This has implications for leaders and managers at all levels who want to improve their own leadership styles. “If you look at existing leadership research, extroversion stands out as the most consistent and robust predictor of who becomes a leader and who is rated an effective leader,” Grant says. “But this tells us little about the situations in which introverted leaders can be more effective than extroverted leaders.” So he and his fellow researchers began looking at the issue through the lens of a business that could easily track productivity and team effectiveness—pizza delivery franchises. The researchers obtained data from a national pizza delivery company and surveyed store leaders and their employees.
Threatened by proactivity
Leaders were asked to rate their own extroversion—the degree to which they commanded the center of attention by acting talkative, assertive, outgoing and dominant. Employees were asked to rate levels of proactive behavior in the store, such as improving procedures, correcting faulty practices, speaking up with ideas and stating opinions about work issues. What Grant and his colleagues found was a simple inverse relationship: When employees are proactive, introverted managers lead them to earn higher profits. When employees are not proactive, extroverted managers lead them to higher profits. “Because extroverted leaders like to be the center of attention, they tend to be threatened by employee proactivity,” Grant notes. “Introverted leaders, on the other hand, are more likely to listen carefully to suggestions and support employees’ efforts to be proactive.”

Pairing an extroverted leader with a proactive team can actually reduce the company’s effectiveness. “Once the extroverted leader responds in a less receptive way, that becomes discouraging and makes team members less willing to work hard or share ideas in the future,” Grant states. 
The T-shirt challenge
The research team also conducted another study that looked specifically at extroverted leadership behavior. They took college students and designated them as team members or leaders in a T-shirt folding group with the goal to fold as many shirts as possible in 10 minutes. Students were assigned to lead in either an extroverted or introverted manner. Extroverted leaders were given examples of famous leaders who were bold, talkative and assertive, such as Martin Luther King, Jr. and Jack Welch. The introverted leaders were given examples of famous leaders who were quiet and reserved, such as Mahatma Gandhi and Abraham Lincoln. Meanwhile, two other graduate students, or “confederates” were paired with each group and secretly told to act either passively or proactively, with the proactive confederates offering a new, efficient way to fold T-shirts.

The researchers found a significant interaction between extroverted leadership and proactive behavior that meshed with the findings from the pizza study. When the confederates were passive, teams performed better when led in an extroverted manner, but when the confederates were proactive, teams performed better when led in an introverted manner. “When the confederates were proactive, participants perceived the more extroverted leaders as less receptive to ideas, and they invested less effort in the task,” the researchers write. 
The implications of the power struggle for the leader-employee relationship and labor relations became very clear, according to Grant. “At some level, the power struggle is finished, with the leader asserting authority and the employees saying, ‘We’re not going to work as hard on your behalf.’” The employees basically decided that “Hey, these leaders are not receptive to good ideas…we don’t really have a ton of respect for the leader. We don’t want this leader to be one of the top performers. We want to feel, at the end of the day, like our ideas are valued and our contributions are appreciated.”
Interestingly, neither the introverted leaders nor the extroverted leaders showed higher productivity or profitability than the other. The difference, Grant and his researchers found, was in the pairing of leaders and employees. “It shows that introverted and extroverted leadership styles can be equally effective, but with different groups of employees,” he says. Our research provides insight into when each style is effective, as opposed to trying to test which one is better— which I think is the wrong question.” 
Creating space for employees
Grant says the study has broad implications for corporate leaders who want to examine their own leadership styles as well as make changes in the lower management ranks. “We tend to assume that we need to be extremely enthusiastic, outgoing and assertive, and we try to bring employees on board with a lot of excitement, a clear vision and direction,” Grant says, “but there is real value in a leader being more reserved, quieter, in some cases silent, in order to create space for employees to enter the dialogue.”

So how can managers actually implement some of the lessons from the study? Grant suggests that once prospective team members have the required skills and expertise, leaders can explicitly look at personality in making the final selection–examining both the employees and the managers, figuring out which teams will work best together.