Women are better than men at faking it, but in this case the "it" means their interest in a man.
At Indiana University, researchers had 54 college students look at a tape of a speed-dating session that had been held in Germany. Without knowing the language, the students were asked to use the body movement and voice tones to figure out how the couples felt about each other.
The results were pretty accurate for the men. But the students couldn't tell what the women were thinking.
In interviews after the speed dating session, the women in that session frequently said they didn't care for the man, even though they were seen flirting with him during the session.
The researchers believe there could be an evolutionary explanation for women's fake interest. They say that because women may wind up having the man's baby, they have an innate need to learn as much as possible about a potential mate.
In that explanation, fictitious flirting may just be another way to draw that information out from a man.