When we think of great leaders, those that come to mind first -- say, Jack Welch, Steve Jobs, or Martin Luther King, Jr. -- tend to be charismatic, larger-than-life figures. Such examples have led to the popular belief, particularly in business, that extroverts have an advantage in their careers. Those who are outgoing, unafraid of the spotlight, and speak their minds and give direction are natural leaders, the conventional thinking goes. While this isn't necessarily wrong, nor is it the whole story, according to researchers from the University of Pennsylvania's Wharton School, Harvard Business School, and the University of North Carolina's Kenan-Flagler Business School. Introverts can be equally effective leaders, says Wharton's Adam Grant, lead author of "Reversing the Extraverted Leadership Advantage: The Role of Employee Proactivity" in a forthcoming issue of the Academy of Management Journal. Interestingly, Grant and his colleagues find, neither extraverts nor introverts perform better in productivity or profits. Instead, the real indicator of success lies in the pairing of each type of leader with different types of employees.

The results of their research boils down to a simple inverse relationship: Introverted leaders produce higher profits when they're leading proactive employees, while extraverted bosses delivered higher profitability when their employees were not proactive and instead prone to taking and following direction.

Put simply, extraverts, accustomed to recognition and high profile, can be threatened by employees who take initiative and offer up their own ideas on how to do things. By contrast, introverted leaders tend to support employees' efforts to think and act independently and thus work better with proactive employees.

While it's worth reiterating that neither style of leadership proved more effective than the other, all leaders can learn from introverted leaders' openness to giving employees' a degree of autonomy. That is, encouraging proactive workers is advantageous to the team and, critically, to the leader. The more control an employee has over the scope of his or her work, and the greater the sense of responsibility for the team's performance, the more likely that employee is to contribute beyond the minimum job requirements.

This research points to a special opportunity for CIOs. When you're up in the C-suite, you might think it's wise to delegate lower-level hiring to your managers. While it's true that micromanaging directors and managers is productive for no one, CIOs could consider taking a closer look when approving hiring decisions. Since the key to a leader's success isn't so much in personality but in the pairing of leaders and team members, the top decision maker in IT has the unique opportunity to ensure the right combination of the work styles and personalities between managers and teams before giving the final approval.