With few aisle-crossing congressional representatives around, it’s no wonder the two sides rarely see eye-to-eye. But negotiation is tough even without the extra complication of politics. Psychologically, it’s harder to negotiate when the outcomes involve losses (such as higher taxes or fewer benefits) than when they involve gains, University of Amsterdam psychologist Carsten de Dreu told the Association for Psychological Science in 2011 after a congressional supercommittee failed to reach an agreement to reduce the national debt.

Likewise, emotion can blind negotiators to agreeable deals. In a study released in 2009 in the journal Psychological Science, researchers had participants play a game often used to study the intricacies of negotiation. In the game, a participant is given a certain amount of money and told to split it with a second person. If the second person accepts the offer, the money is split. If the second person sees the offer as unfair and rejects it, neither gets any money.

Thus, the first negotiator has to consider the likelihood of the second person accepting the split before they make their offer. The researchers found that participants who relied more on their feelings versus logic in playing the game made less generous offers — even though, logically, such offers are less likely to be accepted, resulting in no money for anyone.