Edited by Daisy Yuhas

“Competitive,” “decisive,” “action-oriented,” even “intimidating”: many people invoke these words to describe good leaders. Indeed, several studies suggest extroverted, dominant individuals are perceived as competent, influential leaders in industry and politics. Think of the late former General Electric CEO Jack Welch, Amazon founder Jeff Bezos or Tesla CEO Elon Musk.

But dominant individuals can have shortcomings as well. Such leaders sometimes insist their way is the only way, or they intimidate others rather than taking steps to discuss, debate or consult with colleagues. And that has serious downsides for the companies, organizations and nations that they lead.

In our recent research, we examined some of the unintentional negative consequences of a dominant leadership style. Across eight studies, we explored how such leaders can inadvertently reduce cooperation among their employees by fostering a competitive climate. Past research shows that societies and organizations flourish when members help one another, share information and engage in collective problem-solving. But dominant leadership can stifle those activities. We argue that's because a leader's hyperindividualist approach can foster a zero-sum mindset in which people believe they can progress only at the expense of others.

First, we looked at political leadership, comparing democracies and dictatorships. Although some democratic leaders are aggressive, dictators exhibit extremely dominant behavior. They subjugate others to serve their own best interests. Given our hypothesis that dominance may foster a highly competitive culture, we wondered whether citizens in dictatorships engage in more zero-sum thinking than those in democracies. To test that idea, we examined data from 70 countries surveyed between 1981 and 2014 through the World Values Survey, which seeks to understand people's social, political and cultural beliefs. Residents reported their agreement with such statements as “people can only get rich at the expense of others.” We also looked at their helping behaviors, including how highly they rated the importance of caring for their neighbors. We found that citizens of countries governed by dictators reported greater zero-sum mindsets and were less likely to help others when compared with residents of democracies.

For our second study, we designed an experiment to directly test whether dominance influences how people think about cooperation and competition at work. We recruited male and female professional actors and filmed them in a series of videos. The performers introduced themselves as managers and described their leadership approach to new workplace subordinates. One of these approaches was dominance: leaders described their tendency to be authoritative and decide what is best for the team. The other approach was what we call the prestige style: leaders emphasized how they valued others' input and an egalitarian approach.

We then recruited about 600 participants who watched one of these videos (either a male or female leader in the dominance or prestige condition). Afterward, they rated how much they agreed with statements related to zero-sum thinking and how likely they would be to engage in helping behaviors—such as listening to a co-worker's problems—if they worked for the boss whose video they had just seen. We found that participants who had watched a dominant leader were more prone to express a zero-sum mindset and less likely to help others, compared with participants who had just watched a prestige leader. Gender had no effect: dominant men and women as bosses reduced helpfulness and increased zero-sum thinking among participants.

Finally, we tested whether this finding could be replicated with actual working groups. We surveyed 249 employees in 50 teams, along with their supervisors, at companies in India. We began by asking employees about their leader's tendency to influence based on dominance and about their own zero-sum mindset. Six weeks later supervisors rated their employees' helping behaviors. Employees supervised by a dominant leader reported greater zero-sum thinking. And as their supervisors subsequently revealed, these employees displayed fewer helping behaviors.

Although a number of leadership books and popular coaching manuals celebrate the effectiveness of a confident, decisive leader, our work underscores how this approach may backfire. Managers need to be aware that an assertive or forceful approach could reduce cohesiveness and collaboration. Organizations, meanwhile, should be careful about the people they promote.

Are you a scientist who specializes in neuroscience, cognitive science or psychology? And have you read a recent peer-reviewed paper that you would like to write about for Mind Matters? Please send suggestions to Scientific American’s Mind Matters editor Daisy Yuhas at pitchmindmatters@gmail.com.