Trying to figure out if your partner's angry? Look at his or her body, not face.

When people are at the peak of joy or despair, their body language is a more reliable indicator of their emotions than their face, a new study finds.

"You can't tell from the face alone if something good's going on or bad going on. When people see the faces alone, they're kind of lost," said study co-author Hillel Aviezer, a psychologist at the Hebrew University of Jerusalem. "The body maintains a clear signal of positive and negative."

The findings are detailed today (Nov. 29) in the journal Science.

Most research on reading emotions has focused on the face. A few studies had shown that people rely on body language to read emotion when it clashes with someone's facial expression, but those studies used trained actors in poses, Aviezer told LiveScience.

His research team wanted to see how people use body language to read intense emotions. To do so, his team gathered dozens of images of elite tennis players at the moment they won or lost critical points in high-stakes competitions like the U.S. Open.

"There is lots of money involved, it's lots of ego involved, it's very high stakes. You have a lot of points in the game where people could have very positive emotions or negative emotions," he said.

They showed three groups of 15 participants images of just the face, just the body, or both together, and asked the viewers whether the image showed positive or negative emotion.

People who saw the body — with or without the face — accurately guessed whether the player was happy or distraught. Those who viewed just the faces failed to distinguish between happy and unhappy players.

The team also morphed winning faces onto losing bodies and vice versa, and found that the body cues dictated whether or not viewers thought the players had won.

The findings don't rule out the face from all emotional cues, he said.

"But when things become very intense, the good and the bad merge together, and it's hard to tell if it's positive or negative," he said.

Interestingly, when people saw a body and face together, they said they made judgments based on facial expression — even though they were actually using body cues to interpret the pictures.

"People use information from the body and then they read it into the face," Aviezer said.

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