Adapted from “The Stressed-out Negotiator,” first published in the Negotiation newsletter.

Conventional wisdom, not to mention the popularity of no-haggle car buying, suggests that many people anticipate important negotiations with the same dread they reserve for root canals.

Unfortunately, stressed-out negotiators tend to be less effective than their calmer counterparts, according to research by Kathleen O’Connor of Cornell University; Josh Arnold of California State University, Long Beach; and Andrea Maurizio, also of Cornell. In their experiments, pairs of undergraduate students negotiated issues concerning a hypothetical class trip. The more stress students felt before negotiating, the less value they claimed in the task.

Notably, stress levels were higher among students who perceived the upcoming negotiation as a threat than among those who viewed it as a challenge. When individuals felt they lacked the skills and resources needed to perform well, they viewed the task as a threat and experienced stress. By contrast, those who believed they could meet or exceed the requirements of the task viewed it as a challenge and kept their stress levels in check. Those who approached the negotiation as a challenge also felt less fearful and more confident and optimistic than threatened negotiators.

In the study, students who viewed negotiation as a threat were more passive and, when they did act, spent more time dividing up the pie than exploring tradeoffs that might have expanded the pie. Though they may have been as skilled as their more confident peers, the negotiators who felt threatened chose the wrong tactics—resorting to requests and demands when problem solving was needed.

The lesson is clear: if you tend to fear negotiations, do whatever you can to keep stress levels low. Improve your pre-negotiation confidence by preparing thoroughly, carefully exploring your outside alternatives, and reminding yourself that the other party may be feeling stressed, too. When you can’t control your stress, make an extra effort to stay actively engaged in the process and to collaborate with your counterpart as much as possible.