We've all been on the receiving end of an angry stare - and can probably confirm it's not much fun - but now science has proved the effectiveness of the 'angry face'.

According to research published in Psychological Science, a journal of the Association for Psychological Science, people are more likely to give in to an unfair demand when they are presented with a threatening facial expression.

“Our facial expressions are relatively more difficult to control than our words,” said psychological scientist Lawrence Ian Reed, first author on the research. And because they are harder to control, such expressions are more believable to those on the receiving end as an outward indication of someone's true feelings.

“In this way, facial expressions can carry the weight of our words,” said Reed.

In one part of the research, 870 participants played a "negotiation game" where one participants, acting as the "proposer", would decide how to split $1 with another participant, the "responder". Each person would receive the specified sum if the responder accepted the offered split, but if not then no one would get the money.

But before making a decision, the proposer was shown a video of the responder making a neutral facial expression or an angry one. (The study participants did not know the responder was an actress instructed to portray a certain facial expression in each scenario).

The clips were accompanied by a written demand for either an equal cut of 50% - considered a "fair" amount - or a larger cut of 70% - an "unfair" amount leaving just 30% for the proposer.

Researchers found an association between the offer made by the proposer and the facial expression of the responder: If the responder made an angry face and requested the 70%, the proposer was more likely to give the 70%.

Facial expression had no influence the offer when the responder demanded an equal share, however.

These findings - even though the angry expression was faked - gives us some interesting insight into negotiations and emotions portrayed, whether at home, with friends or in a business setting.

“The idea that bargaining offers are mediated in part by emotions and motivations speaks towards the importance of emotions and their expression in any bargaining situation," said Reed.

"These include not only the division of resources, but also in buying a car or house, and/or disciplining students or children.”

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