Conventional wisdom about showing anger in negotiations is sometimes contradictory: You should hide your true feelings behind a poker face, some say. Others recommend acting angry even if you’re not, as lawyers often do. New findings from negotiation researchers, however, reveal that both bits of advice are too simplistic, and they suggest a more effective tactic for tough negotiations would be making overt, well-timed threats.

A large body of previous work had shown that threatening to walk away from a negotiation is a powerful way to get the other party to give in to your demands. And making these threats later in a negotiation worked better than doing it early, when your counterpart is more likely to think you’re just posturing. The problem, though, is that we usually make threats when we’re angry

The results gave the researchers their first clue. “Anger does encourage folks to concede more and it has this effect because people see an implied threat.” But anger tends to create  “collateral damage,” lingering resentment that makes it less likely for people to want to deal with you in the future. So if you can achieve the same concessions with threats alone, so much the better. Remarkably, even though threatening negotiators got their counterparts to concede more, they created less ill will than did angry negotiators. In a follow-up study, the participants rated the threatening negotiators as more likable than angry negotiators.

So what is it about threats that make them more effective than outbursts of anger? The answer, the research revealed, is perceived poise — being seen as confident and in control of one’s own feelings. That turns out to be important because negotiators’ poise affects the inferences their counterparts make. If I’m angry, I may say things I don’t mean, so my counterpart may believe I’m saying them in the heat of the moment. Therefore, the counterpart is less likely to think that an angry negotiator will follow through with the implied threat. A cold, non-emotional threat, on the other hand, tends to come across as more intentional — and, therefore, more credible.

In brief, anger isn’t as effective as a simple threat in getting people to concede.