New research found that men in competitive scenarios will deliberately anger their opponents if they think it will help them win. The UCSD study, published in the journal Proceedings of the National Academy of Sciences, explored the ways that emotions influence decision-making. Whatever you might think of emotional manipulation in an ethical sense, it is outstanding in a strategic sense.

Via National Geographic:

For the first experiment, the scientists randomly paired participants—140 undergraduate men—and tested the force of their handgrips.

By giving one of the pair the opportunity to anger his opponent by making him do administrative tasks after a first round of tests, the team discovered that the decision-maker strategically angered his opponent when the decision-maker thought it would impair the other's performance—but not when he thought it would benefit his rival.

...In the second experiment, which involved 120 undergraduate men, the researchers pitted two random people against each other in a mentally challenging computer game in which participants realized that angering their opponents would help them win.

That's because making the opponents mad would make them perform less well on their task of shooting a digital target.

The experiments specifically targeted men because, according to the researchers, women's emotions are "harder to study."

He claimed that women's hormones cause a range of emotions over the course of a month that men may not experience.

So, in other words, women might engage in this same kind of emotional manipulation (wouldn't surprise me), but we will NEVER KNOW because menses. Okey dokey then.