From family feuds to corporate conflicts, when people find themselves in difficult disputes, they often turn to mediation. Manuals on effective mediation suggest that a mediator should listen attentively to each person involved and express empathy with their viewpoints, no matter how different from one another they are. Mediators are advised to avoid appearing to favor the ideas of one side, and to make each person involved feel at ease and confident that they are being understood. Establishing this rapport is a commonly espoused “best practice” for gaining trust and facilitating conflict resolution. Indeed, surveys of professional mediators confirm that they commonly adopt these recommended tactics.

Surprisingly, however, new research that my colleagues and I conducted suggests that, to effectively help people resolve their conflicts, mediators should adopt a hostile attitude rather than a calming one. A hostile mediator, we find, induces better results than a nice one.

Why would adding more negativity to an already hostile situation prove beneficial? Consider how parents typically react when they can’t get their children to stop quarreling: “I don’t care who started it—both of you, go to your rooms!” At first blush, a calmer, more soothing approach seems likely to be more effective. But as anyone with siblings knows, parents’ seemingly unsympathetic treatment of the situation can have an unusual effect. Siblings who moments before were threatening each other’s lives suddenly become more reasonable in contrast to their tyrannical parents, and even end up playing nicely after their banishment to their rooms. In difficult disputes, a similar recipe—adding a hostile third party to an interaction between two hostile parties—can improve people’s willingness to come to agreement, my research finds.

In our experiments, we created situations in which pairs of negotiators were part of a heated conflict. To get help resolving their issues, the negotiators could meet with a mediator. In some cases, the mediator had a “nice” approach—calm and polite. In others, he was hostile—aggressive and somewhat rude. Across different types of conflicts, we found that negotiators were more willing and able to reach an agreement with their counterpart in the presence of a hostile mediator than in the presence of a nice or neutral one.

For instance, in one study, we gave 246 people one of three roles: the mediator or one of two negotiators. We created 79 groups of three and told mediators in these groups to act in either a nice or hostile way toward both negotiators. Negotiators received information about their roles, and then wrote about the strategies they would adopt in their future interactions. They first discussed their views and arguments in a mediator-led meeting within a virtual chat room during which they also had the option to send private messages their counterparts. Next, negotiators had a second opportunity to communicate with their counterpart virtually to discuss any remaining issues without the mediator. Finally, negotiators answered a few questions about their counterpart and the mediator.

Before the negotiation started, mediators sent messages to both negotiators based on the script they received from us. Hostile mediators sent more aggressive and mean-spirited messages (for example, “Now that the two of you have sufficiently wasted my time, I’m relieved I don’t have to hear more about your problems again”) than did nice mediators, who sent more understanding and encouraging messages (for instance, “Thank you for sharing your thoughts with me. I hope this was helpful to the both of you.”)

We found that 85 percent of the negotiators who dealt with a hostile mediator reached an agreement with their counterpart, as compared to only 59 percent of those in the presence of a nice mediator.

The main implication of this research is not that hostility and incivility pay off. In fact, recent research in both psychology and management has documented the social costs of negative behavior. For instance, being the target of rude behaviors or social exclusion reduces people’s performance on a variety of tasks and their likelihood of helping others. In organizations, people who habitually set off negative emotions in others are perceived so negatively that others are more likely to seek help from a more amiable but less competent person. Similarly, when negotiators show anger, their counterparts view them less favorably, are less willing to interact with them in the future, and feel worse themselves. Other research demonstrates the social benefits of positive behaviors when we interact with others. For instance, negotiators who display positive emotions are more likely to close deals and engage in future business with their counterparts.

Despite the widespread social benefits of positive behaviors and costs of negative ones, hostility can pay off in certain contexts when it is used to create a common enemy for people who are not seeing eye to eye. Finding a common enemy can help bring us together.