A new Indiana University study finds that some women are extremely good at faking it.

By “it” we mean interest in a man. (What, you thought we meant something else?) They flirt with him, and yet they are thinking: “I wish this guy would just leave me alone. I can’t stand the sight of him.”

For the study, published last month in the journal Psychological Science, 54 college students were asked to watch speed-dating sessions recorded in Germany, then were asked how each party felt toward the other. None of the observers spoke German, forcing them to judge the daters by body language and vocal tone.

Turns out the observers were pretty good at judging how the men felt but almost uniformly terrible at figuring out what some of the women were thinking.

Specifically, some women seemed to be saying, “I’m interested,” and yet they were not, according to what they later reported.

“Both genders had trouble reading what the women were doing,” said Skyler Place, a psychology doctoral student at Indiana who co-wrote the study.

Place said there is some evolutionary rationale for the behavior. Women have a lot more riding on picking the right guy, because a bad choice could mean having that man’s baby. So women could be acting coy to get men to open up more, thus revealing anything that could make him a bad choice, Place said.

It’s also possible American college students just aren’t good at reading the body language and inflections of German women.

Maybe the real question is: How do you say, “Look, I’m just not that into you” in German?