All men need to do is flash a smile at a woman to get her to do his bidding, as suggested by an European study.
The University of Granada study in Spain also found that women assumed a more narrow and submissive posture when a man smiled at them. This man's 'perceived warmth' explained the woman's behaviour, according to the researchers.
Body language expert Patti Wood said the findings were troubling but that it could be because women rely on body language more than men to make decisions.
"Even if there's dissonance between what's been said and what his body is doing, women will look to the body. If they see a smile, then the interaction seems more friendly," said Wood, the Daily Mail reports.
"It's a tricky situation, and one that highlights just how subtly sexism can intrude on interactions. Even if there's dissonance between what's been said and what his body is doing, women will look to the body. If they see a smile, then the interaction seems more friendly," Wood added.
Wood advises women to know what you want before meeting men if they do not want to be manipulated by a man's smile - especially when they are at work. She said this will improve your body language and communication and reduce the number of nervous tics that reveal your anxieties.
Wood, who is based in the US, said: "Smiling can make women seem more subordinate. If you're smiling when giving an important statement, it makes that statement weaker."